Film Critique - Part 1: Chest


Discussion of the diagnostic criteria for routine chest x-rays with emphasis on exposure technique, positioning, pathology, and clinical correlation.

Author: Nicholas Joseph Jr. RT(R) B.S. M.S

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Radiographic Film Critique of the Chest

Written by Nicholas Joseph Jr. RT(R)(CT) B.S. M.S



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Article Navigation:

Objectives

Introduction

Anatomy of the Respiratory Tract

Imaging Considerations

Chest X-ray Anatomy

PA/AP Chest Radiograph

Critique AP/PA Chest Radiographs

Left Lateral Chest Radiograph

Diagnostic Criteria for the Lateral Chest Radiograph

Summary Points

References

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Objectives:

Upon completion, the reader should be able to:





Introduction

Radiographic imaging of the chest, especially the lungs is one of the most common types of radiographs taken. The ďroutineĒ chest x-ray provides information about the bony frame of the thoracic cavity, its soft tissues, the mediastinum, and the lung parenchyma. There are many reasons chest x-rays are ordered by physicians, for examples, persistent fever and cough, pneumonia, trauma, pleural effusion, pacemaker or central venous line placement and many others. Because of the many potential diagnoses possible from the screening chest radiograph the radiographer must have a good understanding of what is in question when taking it. When serial radiographs are taken, the radiologist relies on consistent exposure techniques to evaluate progress of clinical treatments. The technologist encounters various types of pathologies that may be harder to penetrate than normal lung, for example, fluid in the thorax, or a dense mass that may require an increase in exposure. Likewise conditions that trap air in the lung, such as emphysema and chronic obstructive pulmonary disease (COPD) require a decrease in exposure factors. Often patients having repeat exams are imaged by different technologists so that consistency in exposure is difficult to achieve without standardized exposure factors. Consider a request to evaluate placement of a central venous catheter that should be in the superior vena cava. The technologist should note the entry site as part of the preparation for performing the test. Clearing metal such as electrocardiogram leads or snaps on the patientís gown is important to avoid possible artifact superimposition. Post procedural reasons for ordering a chest radiograph may include checking the placement of a chest tube or locating a central venous catheter tip. The point here is that the technologist must know why a radiograph is taken in order to satisfy the diagnostic criteria for the requested study. To illustrate this point, consider a request for a portable chest x-ray for PIC line placement. The technologist may take an otherwise diagnostically acceptable radiograph of the lungs, but not properly demonstrate the distal tip of the PIC catheter. This is because it may require overexposure of the lung parenchyma or use of a grid during portable imaging to reduce image fog and improve subject detail. What is different about film critique of the chest is that the diagnostic standard for imaging is dependent not only on routine imaging criteria, but also on clinical information provided by the ordering physician. In this module we will explore some common reasons for taking a routine chest x-ray. Keep in mind that while the diagnostic criteria for each view will be stated, the actual diagnostic criteria must also include proper exposure to demonstrate the requested diagnosis. This review of chest imaging will include pathology considerations since different types of pathology require change in exposure technique relative to normal lung tissue. But before we get into these more advanced points of imaging, letís review some basic anatomy of the lungs relative to diagnostic radiography.





Anatomy of the Respiratory Tract

The respiratory system is anatomically divided into upper and lower divisions. Functionally the respiratory system is divided into a conducting airway that moves air into and out of the lungs, and the respiratory division where gases are exchanged between the blood and the airway. Respiration is a term that is often misused in that it refers to three distinct functions of the respiratory system: ventilation, gas exchange, and oxygen utilization. Ventilation or breathing is a mechanical process that moves gases, specifically oxygen and carbon dioxide, in and out of the lungs. Gases move from a volume of high concentration to a volume of low concentration by a passive process called diffusion. Oxygen is highly concentrated in the atmosphere relative to its low concentration in the pulmonary artery distribution in the lungs. Likewise, carbon dioxide is highly concentrated in blood moving through the lungs comparative to air in the alveoli. As a result, oxygen moves from air to blood and carbon dioxide from blood to air down their concentration gradients. Proper gas exchange results in oxygenation of blood and exhalation of carbon dioxide. Therefore, the respiratory system is responsible for delivering deoxygenated blood to the lungs where it is oxygenated returning it to the heart by the four pulmonary veins for systemic distribution by the aorta.

The respiratory system is arbitrarily divided into the conducting and respiratory divisions. The major parts of the respiratory system in order from proximal to distal are the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli. The conducting division includes those passages and cavities that deliver air to the respiratory division. The respiratory division is responsible for gas exchange between the blood and air. Ultimately, lung function is to supply oxygen to the bodyís tissues for cellular respiration and remove cellular waste in the form of carbon dioxide gas through expiration. Cellular respiration on the other hand, is a process by which small soluble food molecules are chemically oxidized to release energy in the form of adenosine triphosphate (ATP). The human body only uses carbohydrates, proteins, and fats (lipids) for food. As you may recall, using carbohydrates as a model, glucose when broken down without oxygen generates only 2 energy molecules (ATP) through glycolysis. In the presence of oxygen, Krebsís cycle occurring in the mitochondria of cells can generate 36 energy molecules per glucose molecule. Thus oxygen is necessary at the cell level for maximum energy production. Certain disease states like asthma, chronic obstructive pulmonary disease (COPD), smoking and other destructive lung pathologies reduce oxygen to the body and can cause a decrease in energy production.

Though we will not fully discuss the upper division of the respiratory system some of its members should be mentioned. The nose serves as an air passageway. Here the process of warming air begins. Cilia and mucous membranes lining the nasal cavity trap inhaled dust, bacteria and other foreign materials such as pollen and pollutants. The nose contains olfactory receptors that distinguish various odors and contribute to taste. It also functions in adding quality to voice and phonation. The palatine bones separate the nasal and oral cavities. A defect in the palatine bones called a cleft palate is sometimes seen in newborns. This type of defect may allow abnormal communication between the two cavities, but is surgically repairable in most cases.

The pharynx, called the throat in laymenís terms, is about 5 inches in length and lies just anterior to the cervical vertebrae. It is arbitrarily divided into three parts, the nasopharynx posterior to the nose, the oropharynx or back of the mouth, and laryngopharynx, which is behind the larynx. The pharynx is continuous with the esophagus having seven opening into it: the right and left auditory (Eustachian) tubes, two openings from the posterior nares into the nasopharynx, the mouth opens to the oropharynx, and openings from the larynx and esophagus. The auditory tubes connect the nasopharynx to the middle-ear cavities functioning to equalize pressure in the middle ear. The nasopharynx contains a collection of lymphoid tissue called the pharyngeal tonsils or adenoids. Posterior to the hard palate is the soft palate containing the uvula. When swallowing the uvula is brought upward to close the nasal pharynx so that food does not enter the respiratory system.

The pharynx or throat is about 5 inches in length and lies just anterior to the cervical vertebrae. It is arbitrarily divided into three parts, the nasopharynx posterior to the nose, the oropharynx or back of the mouth, and laryngopharynx, which is behind the larynx. The pharynx is continuous with the esophagus having seven opening into it: the right and left auditory (Eustachian) tubes, two openings from the posterior nares into the nasopharynx, the mouth opens to the oropharynx, and openings from the larynx and esophagus. The auditory tubes connect the nasopharynx to the middle-ear cavities functioning to equalize pressure in the middle ear. The nasopharynx contains a collection of lymphoid tissue called the pharyngeal tonsils or adenoids. Posterior to the hard palate is the soft palate containing the uvula. When swallowing the uvula is brought upward to close the nasal pharynx so that food does not enter.

The oropharynx begins at the soft palate and extends to the hyoid bone. The laryngeal pharynx continues from the hyoid bone to the larynx becoming continuous with the esophagus. The oropharynx houses the palatine tonsils in its lateral walls and the lingual tonsils on the base of the tongue. The tonsils are accessory structures of the lymphatic system whose functions include filtering circulating lymph. The respiratory and digestive systems become distinct at the laryngeal pharynx. Here food is directed posteriorly into the esophagus and air conduction continues anteriorly into the larynx. Therefore, the functions of the pharynx are a passageway for food and air and by changing its muscular shape aids in phonation.

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These sagittal CT images of the upper respiratory tract show the frontal sinus (A), sphenoid sinus (B), nostril (C), nasopharynx (D), oropharynx (E), and nasal conchae (F). The palatine bones that separate the nasal and oral cavities is also seen (yellow arrow). Air is conducted through the nose and oral cavities to the pharynx and larynx. Conduction of air continues from the larynx to the trachea and down the bronchial tree to the alveoli of the lungs. These structures warm, humidify, and clean air of dust particles and heavy debris, conducting it to the respiratory division of the lungs.

The larynx or voice box is the entrance into the lower respiratory system. One of its main functions is to allow air to pass into the trachea and keep food out during swallowing. It also functions in phonation along with the paranasal sinuses and pharynx. It is composed of muscles, ligaments, and cartilage structures. There are nine named cartilages that form the larynx, three are singular and three are paired. The three single cartilages are the thyroid, epiglottis, and cricoid. The three-paired cartilages are the arytenoids, cuneiforms, and corniculates. The most prominent of these cartilages is the thyroid cartilage, commonly called the Adamís apple, which is located on the anterior surface of the neck. Its larger size in males is responsible for deeper voice. The epiglottic cartilage is attached to the superior surface of the thyroid cartilage. During swallowing it closes the larynx so that food is directed into the esophagus. During ventilation it opens to allow air to enter or leave the trachea.

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These two CT images (left-sagittal, right-3D volume rendered) show various parts of the pharynx and larynx. The larynx (A) and trachea (B) are labeled on both CT images. The pharynx is common to the digestive and respiratory systems, but the larynx is part of the respiratory system only. The larynx continues distally as the trachea and the pharynx is continuous with the esophagus; the trachea lies anterior to the esophagus.

Trachea and Bronchial Tree

The trachea, commonly known as the windpipe is the continuous connection from the larynx to the primary bronchi. It begins at the inferior cricoid cartilage at the level of C5 vertebra extending intrathoracic to the level of T5 vertebra. It is a rigid cartilaginous tube about 12 centimeters length and 2.5 centimeters in diameter. It is composed of 16 to 20 C-shaped cartilage rings that open posteriorly. The carina, located at C5 is a reinforcing cartilage plate marking the termination of the trachea as it bifurcates into the right and left primary bronchi. Structurally the cartilage composing the trachea keeps the upper airway open without collapsing during ventilation. The thyroid gland, which is vital to metabolism and growth, lies on the anterior and lateral aspects of the trachea. The esophagus runs posterior to the trachea and anterior to the vertebral column. It is important that the trachea is properly exposed and visualized on the chest x-ray. It should lie in the midline over the lower cervical and upper thoracic vertebrae. Any deviation from the normal anatomical position could represent a mass, pneumothorax, or other pathology. So, it is important that the chest is not rotated when evaluating the trachea.

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Cartilage of the trachea and primary bronchi are abnormally calcified, which allows us to see them on these two coronal CT images. Abnormal calcification of the trachea (white arrow) is responsible for tracheal wall detail seen on these images. Bifurcation of the trachea at the carina (yellow arrow) into the left and right main bronchi (blue and purple arrows) is easily seen. The main function of these conducting structures is to move inhaled air to the lungs and remove carbon dioxide released by metabolism into the atmosphere.
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The coned down radiograph of the neck seen on the far left shows an air filled trachea (arrowheads). On the same radiograph the trachea is seen bifurcating at the carina (broken line). Calcificified cartilage of the carina (yellow circles) permits its visualization on the two axial CT images. At the carina the trachea bifurcates to become the right and left primary bronchi, which enter the hilum of each lung. The carina is radiographically significant because it marks the level of the pulmonary trunk (red arrow).

The bronchial tree is composed of progressively branching tubes that get smaller distally as they extend into each lung. The first part of the bronchial tree begins where it branches into a right and left primary bronchus. The right primary bronchus is wider and more vertical than the left primary bronchus and therefore more prone to foreign body aspiration. Deeper into the lungs each primary bronchus branches into several secondary bronchi that that branch into multiple segmental (tertiary) bronchi. Tertiary bronchi subdivide into numerous smaller branches (approximately 20 orders) called bronchioles.

The smallest order of the conducting airway is the terminal bronchioles; these end the purely conducting portion of the airway. Distal to the terminal bronchi is where gas exchange occurs. These branches still contain some hyaline cartilage to keep the airway open during inspiration and expiration. Successive branching slows the velocity of inhaled air allowing airborne particles to settle along the tubular pathway. During branching, air is warmed to body temperature and moistened before entering the alveoli. The lumen of the bronchi is lined with epithelium containing cilia (hair like projections from the cells) and mucus secreting cells that traps dust and inhaled particles. Cilia sweep mucus back toward the pharynx where it is either swallowed or expectorated.

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This is a volume rendered CT image showing the bronchial tree. In particular, notice its bifurcation into a right and left primary bronchus (blue arrow) that enter the hilum of each lung. The bronchial pathway continues to branch into smaller tubules called bronchioles (yellow arrows) becoming progressively smaller until they reach the terminal bronchioles leading to the alveoli. The smallest branches, the terminal bronchioles are microscopic and are not visible to the naked eye.

Although there is little to no cartilage in the bronchioles, they do contain smooth muscle that allows them to constrict and dilate with thoracic pressure. The respiratory division begins at the respiratory bronchiole, which is immediately distal to the terminal bronchioles. The respiratory division consists of respiratory bronchioles, alveolar duct, alveolar sac, and alveoli. This area of the bronchial tree is called the respiratory division because these structures conduct gas exchange with pulmonary capillaries surrounding them. When air reaches the respiratory division it is clean, moisten, and at a temperature of 37 degrees Celsius. The bulk of each lung is composed of thin walled alveoli, which are the functional units of the lungs. Gas exchange occurs across the respiratory bronchioles down to the alveoli; however, it is the alveoli that conduct most of the gas exchange in the lungs. Thus, the alveoli are the functional units of the lungs and the site where most gas exchange takes place.

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This drawing is a representation of the distal branches of the respiratory bronchi where capillaries surround the alveoli. Capillaries (blue, A) release carbon dioxide into the alveolar spaces (C) and absorb oxygen into them to be distributed to the tissues (red, B). The alveoli are the functional units of the respiratory system where the work of gas exchange takes place. The lungs do not carry out its function of gas exchange until after birth when the lungs are expanded. The lung alveoli continue to develop during the first year of life to become the vast network of functional units illustrated in this drawing. The adult lungs have nearly 300 million alveoli, whereas at birth there are a mere 24 million alveoli.


Lung Development

The lungs begin their development from two primary tracheal buds during the 3rd week of gestation. They are not developed sufficiently to sustain birth of an infant until about the 28th week of pregnancy. Underdevelopment is the result of there being no cartilage in the alveoli to keep them open during inspiration and expiration. Alveoli are prevented from collapsing by liquid surface pressure exerted on the walls of the alveoli. Type 2 pneumocytes (pneumocytes are lung cells) begin to appear about the end of the 6th month of development. They secrete a liquid called surfactant that keeps the alveoli open. A failure of the surfactant producing system causes a condition called hyaline membrane disease causing a premature birth to present with respiratory distress syndrome. This is because infant alveoli require low surface tension to remain open during ventilation. Premature birth before the 7th month of development often results in respiratory failure due to inability of the alveoli to remain open during expiration. Type 2 pneumocytes begin to develop during the last trimester of gestation and continue during the few years after birth. At birth there are twenty four million terminal sac and alveoli present. By eight years of age to adulthood there are approximately 300 million alveoli. Therefore, most of lung development occurs after birth. When imaging the infant chest, especially when premature born, it is important that the technologist use proper exposure. Hyaline membrane disease can improve significantly with time so that the serial radiographs must be made on proper inspiration and free of motion artifact.

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Left - This infant chest radiograph demonstrates hyaline membrane disease (HMD). Hyaline membrane disease is caused by premature birth with poor lung development. Type 2 pneumocytes are poorly developed causing low surfactant production needed to keep alveoli open. Chest radiograph reveals uniform opacity of the lungs and the air-bronchiogram sign (arrows), characterized by bronchi surrounded by non-aerated alveoli and widespread atelectasis. The infant suffers respiratory distress syndrome, which is treatable including providing satisfactory tissue oxygenation through ventilator support and maintaining proper thermal environment. Right Ė normal infant chest radiograph in which the alveoli are well developed and the lungs are able to aerate properly to supply the bodyís needs.

As each lung develops from its lateral primary bud it pushes into a separate coelomic cavity (future pleural cavity). In so doing the lung adheres to the pleural sac becoming surrounded by a double-walled membrane called the pleura. Pleural sacs separate each lung from the other into separate structures that work together. The layer lining the lung is called visceral pleura and the adjacent layer adhering to the thoracic cage is called parietal pleura. Between the parietal and visceral pleura is a very thin space called the pleural cavity. Within the pleural cavity is a small amount of lubricant that reduces friction as the lungs expand and deflate during ventilation. The pleural space is not normally visible except in pathological states like pleural effusion or pneumothorax. Visceral pleura invaginates into the lungs forming fissures that divide the right lung into three lobes and the left lung into two lobes. The right lung has superior, middle, and inferior lobes separated by two deep fissures. Adjacent pleural fissures define lobar boundaries. The right major (oblique) fissure separates upper and middle lobes from lower lobes. A minor fissure separates the anterior portions of the right upper and middle lobes. Thus the lobes on the right are: right upper lobe (RUL), middle lobe (RML), and right lower lobe (RLL). The left lung is divided into superior and inferior lobes by an oblique fissure. Its lobes are abbreviated as left upper lobe (LUL) and left lower lobe (LLL). Accessory lobes such as an azygos lobe or lingual may be present, which are normal anatomical variances.

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These two drawing of the right and left lungs are labeled: (A) RUL, (G) horizontal or minor fissure, (D) RML, (E) RLL, (H) oblique or major fissure, (C) RUL, and (J) base of right lung. Labeled portions of the left lung are: (B) LUL, (I) oblique fissure, (F) LLL.
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The coronal CT image on the left shows the right minor (horizontal) fissure (white arrow), right major fissure (yellow arrow), and left major (oblique) fissure. These structures are also seen on the right lateral sagittal CT image on the right. The minor fissure separates the right superior lobe from the right middle lobe. The right major fissure separates the right upper and middle lobes from the inferior lobe. The left major fissure (middle CT image) separates the left upper and lower lobes. These fissures are easy to see because this patient suffers significant pleural effusions that fill the pleural space and partially separates the lobes.
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These two PA chest radiographs demonstrate normal inflated lungs (left) and a pneumothorax involving the right lung (right radiograph). The pleural space is a potential space between the parietal and visceral pleura with a fluid lubricant between the layers to reduce motion friction. When air is present in the cavity as seen in the right lung on the right radiograph, the lung (arrows) may collapse under pressure. Notice the absence of lung markings throughout the right hemithorax compared to the left hemithorax. Accumulation of fluid in the pleural space is called a hemothorax.


The Mediastinum

Each lung is surrounded by its own pleura separating it from the other lung. The mediastinum is that space between the lungs and pleural surfaces. It covers the area from the sternum anteriorly to the thoracic vertebrae posteriorly. It extends from the thoracic inlet superiorly to the diaphragm inferiorly. There are many structures within the mediastinum including the thymus, heart, trachea, esophagus, thoracic aorta, venae cavae, azygos venous system, pulmonary arteries and veins, lymphatics, and various nerves. All of these structures and their relationships to each other are important. When evaluating the mediastinum it is important that there is symmetry between left and right chest structures on the chest x-ray.

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These PA and lateral chest radiographs are presented to show the mediastinum. The anterior view of the chest seen on the left demonstrates the lateral margins of the mediastinum (yellow lines). The lateral view on the right shows: the superior mediastinum labeled (S), which is above the green line; the anterior mediastinum (A), which is that area anterior to the blue line anterior to the heart surface; the posterior mediastinum (P), which is posterior to the purple line and anterior to the thoracic vertebrae. The middle mediastinum (M) is between the blue and purple lines. Components of the mediastinum includes the heart and great vessels, trachea, esophagus, and others structures.
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These two 3D CT images show some of the structures within the mediastinum. On the left the sternum (S) is the anterior limit of the mediastinum. On the left the heart (H) lies in the middle mediastinum. Other structures such as the great vessels are seen, however, lymph vessels, pericardium, and other structures are not seen. The sternum is removed on the image on the right to show the entire heart and great vessels that fill the mediastinum. An enlarged mediastinum on chest x-ray could represent enlarged heart, aneurysm, dissection, a mass, or normal anatomy.






Imaging Considerations

One of the most commonly performed examinations in radiology departments is the chest x-ray (CXR). While this may seem one of the simplest examinations performed, as we will discuss, is also one of the most repeated exams as well. This is because there are many considerations that must be understood when taking a chest radiograph. The chest x-ray provides information about soft tissue, bone, the mediastinum, pleura, lung tissue, and various types of catheters and tubes that may appear in the lung or heart. Also the technologist must consider the patientís position, the projection of the central ray (CR), and exposure factors that make an optimal radiograph. But what makes the chest radiograph so elusive is that often different technologists may perform serial radiographs so that image consistency is often lost. To assure image and diagnostic quality there must be consistency in how the CXR is performed in an imaging department. Ultimately, exposure factors selected, post processing, patient positioning, and pathological conditions can affect the diagnostic quality of a chest radiograph. Understanding those factors that affect image quality is a must in order to achieve consistently high quality serial radiographs.

Selecting correct exposure factors is one of the most important components in the production of quality radiographs. When serial radiographs are taken, for example a daily portable chest x-ray on an intensive care patient, varying exposures may hide or appear to create pathology. Keep in mind that patient position, source-to-image-distance (SID), milliampere/time (mAs), and kilovoltage (kVp) selections all affect the quality of radiographs. Serial radiographs monitoring the effectiveness of treatment regimens are especially sensitive to serial image quality.

The standard positions for chest radiographs are erect posteroanterior (PA) and the left lateral. Each of these positions places the heart closest to the image receptor since it lies anterior and slightly to the left in most individuals. A source- to-image-distance (SID) of 72 inches is also used since this distance reduces magnification of the heart and mediastinum. The central ray enters at the level of the sixth thoracic vertebra. Portable CXR is performed with the central ray directed anteroposterior (AP). The patient is either supine or upright depending on the patientís condition. For example, during trauma and the patient is on a spine board due to spine precautions the radiograph may be performed supine. In contrast, to check fluid levels in a patient with known pleural effusions but is unable to transport to the radiology department, the patient should be imaged at bedside in the upright position.

When performing the portable CXR most of the variance between technologists involves patient positioning and SID. For example, indicating that the patient is upright can mean the patient is 45-degrees upright, or 90-degrees upright. There is great inconsistency in the meaning of upright among technologists. Upright should mean the patient is as close to 90-degrees as possible and the horizontal central ray is parallel to the floor. The exposure technique is greatly affected by the SID. Keep in mind that the SID selected is affected by the inverse square law, which describes how radiation intensity is affected by changes in distance. An exposure of 90 kVp at 10 mAs will have different effects when the SID is 40 inches vs. 60 inches. Therefore, the SID should not be estimated, it should be measured for accuracy. In addition, standardization of source-to-image-distance during portable imaging is a must in order to achieve consistent quality serial portable radiographs.

Most adult chest radiographs taken in the radiology department use a fixed kVp of 100 to 140, and vary the mAs using automated exposure, such as phototiming. The average exposure for the adult chest radiograph is about 120 kVp. Thus repeating radiographs because of improper exposure is not the main cause of repeats in the department. However, with portable imaging, the exposure varies between technologists based on patient presentation. The risk of improper exposure increases when two or more imaging factors such as kVp and SID are changed simultaneously. For instance, a previous optimal portable chest radiograph was recorded to be taken using the exposure factors: 92 kVp, 8 mAs, 40 inches SID (exposure 1). The technologist takes a new radiograph at 80 kVp, 10 mAs, 50 SID (exposure 2). The characteristics of these two exposures will be different based on their exposure factors. Exposure 1 will have lower contrast and greater overall density than exposure 2. This is because the kVp of the first exposure gives greater penetrability to the x-ray beam. In fact, the kVp is 15% higher than the second exposure, which is equivalent to doubling the mAs. The SID of the first exposure is 40 inches, which also increases the intensity of the x-ray beam. The second exposure will lack detail and density when compared to the first exposure and may limit the reading of the radiograph. Now, if a third exposure is taken a few days later using 90 kVp, 10 mAs, 40 inches SID (exposure C) the overall results will be much the same as exposure A. This is because the kVp and SID remain fairly constant. Setting department standards for chest imaging, especially those factors that greatly affect the scale of contrast (kVp) and radiation intensity (SID) constant will greatly improve exposure consistency for serial portable radiographs.

Exposure factors such as mAs and kVp should be consistently applied for portable chest imaging just as it is for an upright chest radiograph performed in the imaging department. A good example of consistency is the use of fixed kVp for dedicated stationary chest x-ray units and varying the mAs. This is usually accomplished using automatic exposure controls (AEC) that adjust the mAs to the desired preset image density. The reason it is so important that fixed kVp techniques are used in chest imaging is to produce consistent image contrast. Keep in mind that kVp is the primary controller of contrast. In other words, as kVp increases the number of shades of gray also increases. This is called low contrast or long scale contrast imaging. Likewise, decreasing kVp decreases the number of shades of gray in the image. This is called high contrast or short scale contrast imaging. The points here are that when you decrease the number of densities possible on a radiograph, especially of the chest, any pathology outside the contrast range for the exposure will not be seen. This is why it is recommended that chest radiographs be taken using at least 120 kVp for adults. However, for portable imaging the kVp rarely exceeds 90 kVp because the amount of scatter contributing to image fog is great. Low contrast imaging for the chest is desirable because it yields a greater number of densities on the radiograph and a wider range of diagnoses possible. Keep in mind that initial chest x-rays on hospitalized patients are often performed in the radiology department using high kVp technique. Follow up portable images using lower kVp is acceptable because baseline diagnosis has been established.

For portable chest imaging the kVp rarely exceeds 90 kVp. This is because the amount of scatter radiation that causes image fog increases greatly as the kVp increases. Low contrast imaging of the chest is desirable because it yields a greater number of densities on the radiograph and a wider range of diagnoses possible. Keep in mind that initial chest x-rays on hospitalized patients are often performed in the radiology department with the patient standing and using high kVp technique. Follow up portable images using lower kVp is acceptable because the baseline diagnosis has been established.

Peak kilovoltage used is another important imaging consideration that applies to patients who are not ambulatory and are usually brought to the imaging department for a chest x-ray. Often these patients are unable to stand for imaging against the upright Bucky so they are positioned upright and the cassette placed behind their back for imaging. There is no difference between this imaging style and portable imaging because the kVp is about 30% lower than the optimal 120 to 140 kVp. It is important that the technologist does not merely place a cassette behind the patientís back performing a replication of portable imaging. Instead take time to position the patientís back against the upright Bucky, or carefully align them to a grid-cassette so high kVp can be used. Notwithstanding, as we see later in this module, the diagnostic criterion for portable chest imaging technique is a compromise between an optimal low contrast exposure and high contrast exposure.

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This drawing demonstrates a fundamental difference in what is demonstrated with long scale contrast (top) and short scale contrast (bottom) exposures. When we look at a structure or pathology, which is represented on the drawing by the density at the arrow, it is important to understand that it is only visible if a significant number of x-rays pass through the structure and reach the image receptor. This is dependent on photon energy, which determines penetrating power of the x-ray beam. The energy of the photons in the x-ray beam is a function of the kVp. As the kVp increases, so does the number of radiographic densities displayed. Low kVp demonstrates fewer densities because photons are absorbed and do not reach the image receptor. Photons that do not penetrate the part do not reach the image receptor and will not contribute to the image. When comparing the low contrast scale to the high contrast scale, high contrast will not demonstrate the structure at the arrow if this were pathology. This is why placing a cassette behind the patientís back when in the department for an x-ray is not recommended. In department CXR is a higher kVp image than the portable image and is meant to increase the densities on the radiograph when looking for pathology.

For many years film-screen exposure was the standard imaging technology; however, it is also dependent on dynamic film processing conditions. Chemical film processing requires daily quality assurance testing and performance monitoring for accurate image reproducibility. Besides, film exposure is also affected by film speed, screen speed, and manufacturing differences. Processor temperature fluxuations, replenishment rates for developer and fixer solutions, water and dryer temperatures contribute to variable image quality. Automated chemical film processing is now becoming obsolete although it still remains in use in many institutions. Digital imaging and digital processing is the premier technology for quality imaging and consistent imaging results. Technologies like computerized radiography (CR) and direct digital radiography (dDR) produce exceptional contrast and subject detail. Furthermore, soft tissue detail is superior to film-screen radiography.

A digital radiographic image is first formed as an electronic image that is displayed on a grid called a matrix. The image is laid out in rows and columns called an image matrix. Each image is made of thousands, preferably millions of small cells that make up the image matrix. Each cell in the image matrix is called a picture element, or pixel. With digital imaging, each pixel will have a numerical value that determines the brightness (density) or other details of the cell. Each box has its own dynamic range of values according to the number of bytes of processing; this is called a gray-scale range. Remember that for one byte there are 256 possible values for the density of each pixel, and with 16 bit processing there are 65,535 possible densities any cell can have. These densities can be correlated with the energy of the photons that strike phosphors in the recording medium from which the image will be reconstructed. So, if we use for example, 16 bit processing, and millions of cells in our matrix, we can have tremendous latitude for exposure and image detail. Using our binary code of ď0Ē and ď1Ē a different density is assigned for each of our 65,535 numbers in our gray scale range. The brightness of the phosphor corresponding to that area covered by each pixel can be assigned.

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This digital chest radiograph shows great detail and contrast created by many shades of gray pixel values. On the right is a magnified portion of the radiograph showing many small square pixels. As you can see there are a large number of different densities that make up the digital image. The brightness of pixels can be further manipulated by the radiologist by ďwindowing or levelingĒ the image.

Digital imaging is usually coupled to digital viewing through a picture archiving and communication system (PACS). Images can be manipulated during viewing through a process called windowing and leveling. Window parameters control how light or dark an image is, and level controls the ratio of black to white display, or contrast. An over penetrated radiograph that would otherwise be repeated can within great margins of latitude be adjusted. However, an underpenetrated radiograph may not be darkened or given sufficient contrast to provide diagnostic detail. Optimal kVp range for the adult chest x-ray is 100 to 140, though most PA chest radiographs are still acquired at 120 kVp. Using automated exposure the technologist is able to increase the phototimer density setting using the +1, +2, +3, or +4 setting. Each increase in the phototimer setting is equivalent to about a 25 percent change in the mAs. Thus the exposure can be increased for large patients and decreased (-1, -2, -3, etc.) for a thin patient or those with chronic obstructive pulmonary disease (COPD). High kVp chest images are more accurately manipulated through windowing/leveling processor parameter. Keep in mind throughout our critique that some digital images are evaluated by traditional static film criteria; however, they are not repeated, but are adjusted by the radiologist during interpretation.





Chest X-ray Anatomy

An accurately positioned chest x-ray will demonstrate the lung apices, lung bases, medial and lateral lung fields, and the costophrenic angle of each lung. An air filled trachea is seen superimposed in the midline of the upper thoracic vertebrae. The heart silhouette should be seen without rotation and the lower thoracic vertebral bodies slightly transparent through the mediastinum. The PA or AP chest radiograph displays a wide range of structures with many superimpositions having various radiographic densities. Furthermore, overlying mediastinal or bony structures may obscure portions of the lungs. Therefore, it is important that image quality be optimal and positioning accurate for diagnosis of subtle abnormalities. Some of the structures that should be clearly demonstrated are labeled below:

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Right clavicle (A), right scapula (B), right fourth anterior rib (C), right eighth rib (D), right costophrenic angle (E), left lung apex (F), aortic arch (G), hilum (H), heart (I), left lung base (J), right hemidiaphragm (white arrow).

The lateral chest view is orthogonal (at 90-degrees) to the PA or AP chest radiograph. It allows for visualization of anterior to posterior structural relationships. The retrocardiac region, especially the left lower lobe and retrodiaphragmatic lung bases are demonstrated. Some detail about the thoracic vertebrae is also seen although there will be superimposed structures on the spine. Accurate positioning and optimum exposure is necessary to demonstrate all structures that are systematic evaluated on the lateral chest radiograph. The proper anatomical positioning for the lateral chest radiograph is seen below and some structures are labeled:

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Structures that should be demonstrated on the left lateral chest radiograph include: esophagus (A), trachea (B), lung hili (C), heart silhouette (D), lung apices (E), scapulae (F), thoracic vertebra (G), thoracic intervertebral foramen (H), superimposed posterior ribs (I), costophrenic angles (J), and diaphragm (yellow arrows).



PA/AP Chest Radiograph

There are definable standards by which each chest x-ray projection is evaluated. The diagnostic criteria include patient positioning, exposure technique, structures demonstrated, and proper inspiratory effort. The PA chest x-ray is taken with the patient erect, on full inspiration, patientís chin extended out of the lung fields, the scapula rotated out of the field, and if the patient has large breast move them upward and out away from the lungs. When these techniques are employed the chest x-ray will be without rotation and will meet maximum diagnostic evaluation criteria for patient positioning. In addition to accomplishing the diagnostic criteria for chest imaging, certain principles are practiced that reduce patient radiation exposure in keeping with ALARA. Specific practices include use of good collimation and gonadal shielding of all patients, especially those in the reproductive years of life.

It is important that the PA chest radiograph is well penetrated so that peripheral pulmonary vessels are demonstrated; vertebral bodies are seen through the mediastinum, and retrocardiac and retrodiaphragmatic pulmonary vessels are seen. The left lateral should be well penetrated so that the right lung is demonstrated superimposed on the left lung, thoracic vertebral bodies and intervertebral disc spaces are seen, heart and lung densities show good penetration, and bronchial and vascular markings are clearly displayed.

The goals to be accomplished by positioning the patient for the PA chest x-ray is to accurately demonstrate lung pathology, show air-fluid levels when present, and correctly display the mediastinum with minimal magnification. Secondary goals include reducing repeat rate associated with improper collimation, incorrect exposure technique, poor inspiratory effort, and patient motion. Body habitus must be considered when performing the PA chest x-ray. There are four types of body habitus: sthenic, hypersthenic, asthenic, and hyposthenic. The average body type, which is seen in about 50% of the population is the sthenic type. Most technologists do not have any problem positioning this body type because the lungs will fit on a 14 x 17 inch cassette turned lengthwise. The hypersthenic type (5%) presents with a massive broad deep thorax. The lungs are generally short and wide, therefore, these types usually do not fit on the standard 14 X 17 inch cassette or image receptor lengthwise. To avoid clipping the costophrenic angles the cassette is turned crosswise. The asthenic (10%) body type is long and slender. The thorax is narrow in width, shallow in the anteroposterior dimension, and vertically long. It is easy to over collimate the lung fields lengthwise clipping the costophrenic angles. The hyposthenic (35%) body type is close to the average body type; however, care must be taken not to over collimate vertically clipping the costophrenic angles.

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The PA chest radiograph on the left was taken of a person having the hyposthenic body type. The right radiograph demonstrates a person having the hypersthenic body type. The image receptor is positioned in the lengthwise position for sthenic, hyposthenic, and asthenic types, but is turned crosswise for hypersthenic body types to avoid clipping the costophrenic angles.

Good inspiration is accomplished by having the patient perform a double ventilation technique. First, the patient inhales followed by exhaling; then the patient is asked to inhale a second time and hold it, which allows them to take in more air to expand the lungs. Taking two inspirations prior to exposure should be rehearsed with the patient to achieve better cooperation. Proper positioning of the image receptor is important because deep inspiration increases the thoracic volume in three dimensions. The vertical dimension increases as the diaphragm contracting downward. The thorax increases in the transverse and anteroposterior diameters as the ribs swing upward and outward. The number of ribs superimposed on the lungs determines the degree of inspiration on the chest x-ray. Good inspiration in the adult will display a minimum of 10 posterior ribs, which are counted at their attachment to the thoracic vertebrae to assure accuracy.


Diagnostic Criteria for PA Erect Chest Radiograph
  • All potential foreign bodies such as necklaces, body piercings, bra, sequins, and some fashion printed shirts that may cause an artifact should be removed. The patient may be required to change into a gown when clothing is questionable.
  • All chest radiographs should be made with the patient upright so that the thoracic vertebrae are perpendicular to the central ray.
  • The CR should be perpendicular to the MSP, a horizontal beam to demonstrate air/fluid levels.
  • A 72-inch SID should always be used since this decreases magnification of the heart silhouette.
  • High kVp (100-140) to produce a low contrast image and properly penetrate the lungs and mediastinum. A properly exposed radiograph will demonstrate the vascular lung marking and slight visualization the thoracic vertebral bodies through the heart shadow. The retrocardiac and retrodiaphragmatic pulmonary vessels should also be seen through the heart silhouette.
  • The PA/AP chest x-ray is taken on deep inspiration filling the trachea and lungs. Inspiration should adequately visualize at least 10 posterior and 8 anterior ribs.
  • The chest should not be rotated evidenced by symmetry of the sternoclavicular joints. The costophrenic angles must be entirely included. The apices should project about 1 inch above the 1st rib. The scapula should be seen slightly superimposing the ribs.
  • A position marker, which is usually an arrow indicating upright or supine, and an anatomical marker to indicate left or right side must appear on the radiograph

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The photograph on the left shows proper positioning of a patient for the PA chest x-ray. Notice the chin is extended, hands on waist and shoulders rolled forward and downward. The collimated area is limited to the lungs (yellow dotted box). A lead apron drapes the lower abdomen and pelvis (yellow arrow) to protect the gonads. The radiograph on the right shows a properly made PA chest radiograph that meets the diagnostic criteria. It shows low contrast with good penetration of the medial lung fields and thoracic spine. It also shows deep inspiration as 10-11 posterior ribs are seen. Position and anatomical markers are present on the radiograph as required.

The supine or bedside (portable) AP chest radiograph is used when the patient is debilitated, seriously ill, unstable, or in some trauma scenarios. In most cases where the portable supine chest radiograph is taken there will be various factors contributing to acceptance of a less than optimal image. Often it is not possible to remove all radiopaque objects such as monitor leads, life support apparatus, and the like. Keep in mind that the supine AP portable view does offer a quick assessment of the patient, and when properly made can be a sufficient replacement to the upright chest radiograph. The challenges for the technologist are to include the entire lung fields, reduce magnification, limit chest rotation, and penetrate the mediastinum without burnout of the lung markings. Another challenge is to get a deep inspiration free of motion artifact. Being supine often results in poor inspiratory effort, which results in low lung air volume, increased basilar density, and vascular crowding. The supine chest radiograph can present normal anatomy in a way that often mimics congestive heart disease in the elderly as the heart can be significantly magnified.


Diagnostic Criteria for AP Supine Chest Radiograph
  • All potential foreign objects such as necklaces, body piercings, bra, sequins, and some fashion printed shirts that can cause an artifact should be removed. Heart monitor leads, intravenous lines and such that can be moved out of the main lung fields should be moved.
  • The CR should enter the chest at the level of T7 and perpendicular to the cassette. The patient is often at varying degrees upright rather than truly supine.
  • Most supine chest projections are performed at 40 to 60 inches SID and the central ray vertical. This will cause the heart to appear magnified.
  • High kVp (80 to 90) to produce a low contrast image and properly penetrate the lungs and mediastinum is preferred. A properly exposed radiograph will demonstrate the vascular lung marking and slight visualization the thoracic vertebral bodies through the heart shadow. Plural effusion and other pathologies may obstruct visualization of lung markings compared to the erect position.
  • The radiograph is taken on deep inspiration filling the trachea and lungs. Inspiration should adequately visualize at least 8 posterior ribs. The lungs will appear denser since there is less inspiration than when erect.
  • The chest should not be rotated evidenced by symmetry of the sternoclavicular joints. The apices and costophrenic angles of the lung bases must be entirely included. The scapula is seen slightly superimposing the ribs.
  • A position marker, which is usually an arrow indicating supine, and an anatomical marker to indicate left or right side should appear on the radiograph.

Now letís view and critique some radiographs using the diagnostic criteria for the AP/PA projection of the chest.


Radiograph #1

image001 This patient was unable to get a CT scan because the nurse was unable to get intravenous access. A PICC line was inserted from the right antecubital fossa. Does this AP upright portable radiograph meet the diagnostic criteria for a chest view for PICC line placement?

Critique of Radiograph #1

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This radiograph fails the diagnostic criteria for several reasons including artifact in left lower lung field, failure to include both costophrenic angles, and improper exposure technique for demonstrating the PICC line. Although the lungs are not the central focus of this radiograph both costophrenic angles are clipped sufficiently to warrant repeating this film. Note the pen in the pocket on the left lower lobe of the lung field obscures anatomy (red arrow). Removing all metallic objects is required for all x-rays because it could obscure an incidental pathological finding. Had this radiograph been made using screen-film imaging it would have to be repeated because the PICC line is not clearly seen (yellow broken circle-left radiograph). But because of digital imaging the radiograph was windowed for more density and contrast. The magnified portion of the radiograph (right) shows the effect of changing the density with a digital image. The PICC line is seen in the subclavian vein (yellow arrow).

Radiograph #2

image002 This patient complained of chest congestion following 2 days hospitalization. Patient refused to be transported to the radiology department for an upright PA and lateral chest x-ray. Her physician ordered a portable AP CXR instead. Give your critique of this portable upright AP chest radiograph.

Critique of Radiograph #2

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It is quite obvious that the patient may be a little uncooperative; however, taking a little time to get cooperation is well worth the final results. The patient is leaning to the right, which slightly alters the anatomy at the lung bases. As a result proper collimation was not applied and both arms are in the field of view. This is not in keeping with the practice of ALARA. The curled wire in the upper part of the chest should have been moved. The exposure technique displays good penetration of the lungs and visualization of lung markings is adequate. All required anatomy is demonstrated on the radiograph. This radiograph is not optimal and should be repeated with the patient straight, artifact removed, and applying good collimation in keeping with ALARA.

Radiograph #3

image003 This PA CXR was taken to evaluate PICC line placement and the lungs for possible pneumothorax. The lung fields are also questioned because of chest congestion complaints. Does this radiograph meet the diagnostic criteria for the PA CXR? Keep in mind that this radiograph is a digital image using a dedicated chest unit.

Critique of Radiograph #3

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Again, this is a radiograph that obviously misses the diagnostic criteria for the PA CXR because both lung fields are not included. The right costophrenic angle is clipped; however, before we repeat this radiograph we have to consider two other finding on this radiograph. Notice the PICC line (red broken circle) is seen in the left jugular vein. The area in the red circle is magnified on the right to show the PICC line tip (red arrow). The astute radiographer would not repeat this radiograph since the PICC line needs to be repositioned and the radiograph repeated. So, in keeping with ALARA, repeating this radiograph to show the right lung field would not be necessary. However, when this radiograph is repeated use proper shielding and close collimation to reduce unnecessary exposure to the abdomen.

Radiograph #4

image004 This patientís physician requested a portable chest x-ray to evaluate treatment for congestive heart failure and known pleural effusions. What considerations should the technologist make when performing this radiograph, and tell whether or not it meets the diagnostic criteria for the AP upright portable CXR.

Critique of Radiograph #4

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The technologist should consider that when serial radiographs of a patient are taken it is important that the radiologist can compare them for improvement related to treatment. Because fluid levels in both lung fields are in question the patient should be brought to a true upright position. Notice that the radiograph is labeled upright, but fluid in the pleural space surrounds the upper part of the left lung field (arrows). As a result, vascular lung markings are obscured. Notice the stomach is distended and does not show fluid levels because the patient is not fully upright. Being supine has also produced low inspiratory effort. This findings confirm the patient is really supine or at an angle less than 45 degrees upright. The exposure technique does not adequately penetrate the lung bases. Serial radiographs to evaluate fluid must be made the same way with good fluid penetrating technique. An increase of 15% kVp would be an adequate exposure. Fluid levels in the chest cannot be assessed and is the main reason this radiograph does not meet the diagnostic standards for the AP portable chest x-ray. Getting the patient upright and the x-ray beam horizontal to the floor will accurately demonstrate fluid in the lungs.

Radiograph #5

image005 The patient history for this portable AP chest x-ray includes pleural effusions bilaterally, chest tube on right, and obesity. Does this radiograph meet the diagnostic criteria? If no, then what could be done to make this an acceptable radiograph?

Critique of Radiograph #5

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Again we see an example of the technologist marking the radiograph upright when the anatomical indicators show that the patient is more supine than upright. In particular the stomach, which is filled with air (green arrows), does not show fluid leveling. Also, fluid in the lungs (red arrows) show no leveling as it would if the patient is 90 degrees upright and the x-ray beam directed horizontal to the floor. Although the technologist passed this radiograph it does not meet the diagnostic criteria for the portable AP CXR. This patient has a chest tube (blue arrow) to drain excess fluid; therefore, the patient should be upright for all serial radiographs to assess fluid. The exposure technique does not adequately penetrate the costophrenic angles or display location of chest tube openings draining fluid. Increasing the kVp by 15% will provide adequate exposure. Better collimation could also be used in keeping with ALARA.

Radiograph #6

image006 What is your critique of this upright portable chest radiograph taken to evaluate the lung fields?

Critique of Radiograph #6

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This patient is adequately positioned upright position, although the clavicles show asymmetrical with slight rotation to the right. What stand out most about this radiograph is poor collimation and high contrast. Thoracic vertebral bodies are not visualized through the heart silhouette, neither are the retrocardiac vessels clearly seen. The central focus of this radiograph is the central line (yellow arrow), which is faintly seen. A high contrast area in the abdomen (blue asterisk) confirms this is a low kVp exposure. If a patient is large and you need to see the PICC line, use a grid cassette. Taking oneís time to position the grid so you can use high kVp technique is well worth the diagnostic quality. Collimation to the lung fields (yellow dotted line) will also improve this view. At most institutions this radiograph would not be repeated; however, it does contain those errors mentioned that should be avoided.

Radiograph #7

image007 This PA upright chest x-ray was taken on an ambulatory patient with a history of shortness of breath, smoker. What is your critique of this radiograph?

Critique of Radiograph #7

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Overall, this is an acceptable radiograph. There is some rotation of the chest. The trachea is reasonably midline although the clavicles are not symmetrical. Have the patient stand flush on the floor, shoulder depressed, hands on waist with scapula rolled toward the image receptor. The chin should be over the top of the Bucky with the head straight. These preparations will help align the neck and chest. What could have been done to improve this radiograph is good collimation. Though a chest radiograph is considered low radiation dose compared to a CT scan or fluoroscopy, unnecessary exposure is still of concern. Using a lead shield is also recommended to protect the abdomen during the exposure. These principles are in keeping with ALARA. Otherwise, the exposure technique is adequate for visualizing required anatomy. This radiograph does not need to be repeated because of poor collimation.

Radiograph #8

image008 This radiograph was taken to localize a newly placed PICC line. Does this radiograph meet the diagnostic criteria for the AP chest radiograph?

Critique of Radiograph #8

image0026

At first glance this radiograph may appear to meet diagnostic criteria, but with close inspection we see it is grossly underpenetrated and lacks mAs. The lung fields can be evaluated for pneumothorax; however, not being able to see the thoracic vertebral bodies through the heart silhouette indicates low kVp. As for the PICC line (white arrow), it appears to be logged in the left arm vein. The technologist did properly include the medial portion of the left arm. Keep in mind this is a high contrast exposure evidenced by the bright area over the abdomen (yellow arrow). A portion of the arm is magnified and darkened; however, because the exposure lacks mAs and kilovoltage the PICC catheter is not easily seen. This radiograph should be repeated using at least a 15% increase in kVp and possibly an increase in the mAs. Whether or not the catheter should be adjusted and how much cannot be determined from this radiograph.

Radiograph #9

image009 This patient was too sick to stand for their chest x-ray; therefore, the technologist performed an AP upright study with the patient in bed. What is your critique of this radiograph?

Critique of Radiograph #9

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Performing a high quality radiograph can be difficult depending on patient presentation. We must always keep in mind that serial radiographs are performed to monitor treatment progress. Therefore, we should put our best effort into each radiograph performed. In this case performing the study with the patient upright, proper alignment of the tube-part-cassette, and increasing the kVp would produce a better radiograph. As for exposure technique, better penetration of the costophrenic angles and demonstrating the retrocardiac lung marking is the diagnostic standard for the chest exposure technique. When the lower thoracic spine is seen through the heart silhouette and the medial left lung is demonstrated, the exposure technique is optimal. This radiograph should be repeated using greater kV to penetrate the lung bases. Correct alignment of the patient is also desirable when this radiograph is repeated. This includes having the CR enter at the level of T6 so that the concentrated part of the beam is over the lower thoracic vertebrae. To get an optimal exposure place the patient against the upright Bucky , use at least 120 kVp, and automated exposure control.

Radiograph #10

image010 Give your critique of AP supine chest x-ray taken on a newborn infant to evaluate lung fields, nasogastric tube, and umbilical line placements?

Critique of Radiograph #10

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This is a good radiograph of the infant chest. Notice that the exposure technique adequately penetrates the thoracic vertebrae. The head is straight so that the clavicles are not rotated. When performing a pediatric chest x-ray, it is important that the chest is not rotated. The trachea should appear in the midline over the cervical and upper thoracic vertebrae. A non-rotated chest allows for accurate evaluation of the mediastinum so that the border of the heart and thymus is distinct. Good alignment can help identify anatomical variance due to congenital disorders (e.g. tetrology of fallot, dextrocardia, etc). Proper collimation was applied vertically to include the nasogastric tube (blue arrow) and umbilical catheter (red arrow). Overall, this is an excellently positioned and exposed chest x-ray. Optimally, the proximal portion of the NG tube should have been moved upward out of the field. The left chest lead could have been moved from the lower lung field. Overall, this is a good radiograph that does not need repeating and meets diagnostic standards.

Radiograph #11

image011 This patient was sent to the radiology department for an upright chest x-ray to check progress of treatment for various lung disorders, and to evaluate a newly place PIC catheter. The patient receives continuous oxygen at 8L. What is your assessment of this radiograph?

Critique of Radiograph #11

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What is good about this radiograph is that the technologist demonstrated the PICC line from its entry in the left arm (yellow arrow) to the tip (red arrow). Difficulty advancing the catheter is a reason to include the arm and a portion of the neck. The main issue with this radiograph is the poor exposure technique. Notice that we cannot see the thoracic vertebral bodies through the heart silhouette. As a result the lung parenchyma is poorly visualized and the tip of the catheter is barely seen. The location of the catheter, especially the tip can be determined from this radiograph. Anytime the chest is imaged for catheter placement or chest tube it is important that the lungs are evaluated. Repeating this radiograph given the clinical history to evaluate PICC placement would be a breach in ALARA. However, for future reference increase kVp and collimate to the area within the dotted lines in keeping with ALARA. This radiograph does not meet all components of the diagnostic standard, but is diagnostic for the clinical history given.

Radiograph #12

image012 What is your assessment of this supine portable AP chest radiograph? Patient history was simply evaluate lungs, shortness of breath.

Critique of Radiograph #12

image012

The patient is not well centered to the cassette causing the left lung base to be partially clipped. Notice that the right sternoclavicular joint is projected away from the spine and the right SC joint is over the spine. This is a grossly rotated chest radiograph. The patient should be rotated towards the left until the shoulders are flush against the cassette. Alternately, a radiolucent sponge placed under the right chest to rotate the shoulders equidistant distant from the cassette is acceptable. Adjusting patient position will allow for visualization of the medial right lung field. Exposure does not need to be adjusted for this radiograph when it is repeated.

Radiograph #13

image013 A portable radiograph was taken on this patient with known pleural effusion(s) now suffering decreased oxygen saturation readings. Why is this radiograph not acceptable for a portable AP view of the chest?

Critique of Radiograph #13

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The main reason this radiograph is not acceptable is that it was performed supine rather than upright. Notice the position marker in the upper left corner (yellow broken circle). When a patient history of pleural effusion is given every effort should be made to position the patient upright. There is obvious fluid in the left lung (yellow arrow); however, it cannot be accurately quantified to previous radiographs unless the patient is upright. Newly developing pleural effusion in the right lung cannot be fully assessed since a portion of the right costophrenic angle is clipped. Suggest repeating this radiograph with the patient properly centered on the cassette not to clip required anatomy, and upright. The exposure technique appears adequate for this patient.

Radiograph #14

image014 Patient had increasing shortness of breath, the ordering physician wanted to evaluate the lungs for fluid. Does this radiograph meet the diagnostic criteria based on the history for the exam?

Critique of Radiograph #14

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This radiograph was taken with the patient supine, which is not recommended when evaluating the chest for fluid. An accurate assessment of fluid quantity does require the patient is positioned upright in a manner that can be duplicated for serial radiographs. Notwithstanding, the exposure technique demonstrates poorly penetrated lung fields. There may be patchy infiltrates (yellow arrowheads) developing, which are difficult to see because the chest is under penetrated. There is gross rotation of the chest with the left sternoclavicular joint projected away from the spine. When this radiograph is repeated, roll the patient towards the right until the shoulders are at equal distance from the cassette. Even with a good exposure that penetrates the chest the lung parenchyma would be poorly demonstrated. To optimize this radiograph one must use a grid. Although tube-part-grid alignment is difficult to achieve, it is necessary in order to get it good results on this patient. Use of a grid, increase the kVp, and performing the study with the patient upright are the best way to achieve a highly diagnostic radiograph for this patient. Also, center the patient so that the right costophrenic angle is not clipped.

Radiograph #15

image015 The patient history for this radiograph stated ďchest tube is not working properly, evaluate placement.Ē Based on this history, does this radiograph meet the diagnostic criteria, and state what could have been done to make it a better radiograph?

Critique of Radiograph #15

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Convenience is not a reason to perform a radiograph in the supine position. Based on the clinical history this radiograph should be performed in the upright position. Often patient instability is the factor that determines whether or not a patient should be positioned upright or supine. The supine position should be used only when the physician indicates it or the nurse caring for the patient recommends it due to the patientís condition. Examples of scenarios in which the supine position is indicated include among others unstable low blood pressure, trauma spine precaution, post cardiopulmonary resuscitation, and the like. About the radiograph, the upper chest catheter opening is positioned high, which is great for suctioning air, for example, a pneumothorax. In this case the chest tube has a second opening which should be draining fluid from the chest, which is not appreciated on this radiograph. On the right, the lower left lung field is darkened and magnified to show the lower chest tube opening. This is what the physician wanted to see along with fluid level to determine the catheter is properly positioned in the fluid of the chest. Performing this radiograph with the patient upright is necessary to quantify fluid level. Increase the kVp and position the patient upright when this radiograph is repeated, and include both costophrenic angles.

Radiograph #16

image016 This radiograph was taken on a patient who is receiving ventilated breathing support. The technologist thought it would be easier to perform this radiograph supine since the history for exam is to evaluate endotracheal tube placement. What is your critique of this portable radiograph?

Critique of Radiograph #16

image0031

Although the patient is not aligned to the cassette the reason this is not an optimal radiograph is that the chest is rotated. The left sternoclavicular joint is widely displaced away from the spine. This distorts the radiograph coupled to the poor alignment of the patient to the cassette. Most radiologists would not require this radiograph to be repeated since it is for tube placement, but unmistakably this is not an optimal radiograph. For future reference, align the patient and reduce rotation of the chest by making sure the shoulders are equal distance from the cassette. Although the exposure demonstrates the vertebral bodies through the heart silhouette, this is not the recommended low contrast exposure. Though difficult to see the endotracheal tube tip is noted to be in the right main bronchus (yellow arrow). A magnified portion of the chest is shown on the right to help you to see it better. The problem with this radiograph is it is under penetrated and is badly rotated. Since the endotracheal tube is in the right bronchus this radiograph should not be repeated until after the endotracheal tube is adjusted. The kVp should be increased approximately 15% to better penetrate the lung and produce low contrast. The reason this radiograph was taken supine is that the patient was sedated and on a ventilator. This is acceptable considering the reason for the study was to check the placement of the endotracheal tube.

Radiograph #17

image017 This radiograph was requested on a patient who was sent to the radiology department on a gurney because of depression. A chest x-ray was requested because the patient complained of chest pain and had a normal electrocardiogram (EKG). Does this radiograph meet the diagnostic criteria for a chest x-ray considering clinical history?

Critique of Radiograph #17

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This radiograph shows good positioning of the patient with both sternoclavicular joints symmetrical and lateral to the spine. The apices of the lungs are about 1 inch above the clavicles and the heart and trachea are anatomically projected. The exposure does not demonstrate the vertebral bodies through the heart, but is adequate for this patient. Unfortunately, this radiograph was performed with the patient supine rather than upright. No spine collar is seen, nor any indication that the patientís condition warranted being supine. Otherwise, this is an optimal supine radiograph for the patientís presentation.

Radiograph #18

image018 This patient presented to the radiology department for a routine chest x-ray. The technologist performed the study upright as the patient was able to stand. What condition caused the chin to be in the upper lung field and how should the technologist approach repeating this radiograph?

Critique of Radiograph #18

image018

his patient obviously had difficulty with the upright position due to a condition called chronic kyphosis. This type of body presentation will often have the chin down, stiffness, and weakness of the neck muscles. It is difficult for the patient to extend the neck out of the upper chest field. Therefore the study should be performed upright with the x-ray beam directed AP rather than PA. It may be necessary to tape the head up and out of the field of view. Notice that the clavicles are projected down into the lung field below the fifth rib. Angling the tube cephalic in this case could prove useful. So repeat this radiograph with the head out of the field of view, correct chest rotation, and possible use cephalic angulation to clear the lung fields. The exposure technique is adequate for this view. The inspiratory effort by the patient is satisfactory but not optimal.

Radiograph #19

image019 What is your critique of this portable chest radiograph performed on an obese patient whose chief complaint was shortness of breath?

Critique of Radiograph #19

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This radiograph is an example of the technologist properly aligning the patient to the upright Bucky with the central ray entering at about T6, yet the finished product is unsatisfactory. The patient is upright, the chest shows minimal rotation, and the required anatomy is demonstrated on the radiograph. Because the patient is obese and have large amount of breast tissue, the costophrenic angles are poorly penetrated. Increasing the kVp alone will not compensate sufficiently to make this an optimal radiograph. The patient will have to move the breast up and outward away from the chest. The technologist should increase the mAs by adjusting the automated exposure control to +1 or better +2 gain a 25 to 50% increase. The goal is to achieve an exposure that demonstrates the medial lung bases and costophrenic angles. So repeat this radiograph having the patient move the breast and increase the mAs at least 25 to 50%. Otherwise this is a well-positioned radiograph that includes all required anatomy.

Radiograph #20

image020 This radiograph obviously does not meet diagnostic standards. What should be done to make this an acceptable radiograph?

Critique of Radiograph #20

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A patient with extreme chronic kyphosis can be challenging, but this is one example of where patience and technical skill is most required. The oxygen tubing obstructs the field and the patient is grossly rotated. Poor centering, metal snap from the gown, and obvious lack of collimation are all reasons this radiograph should be repeated. To correct this radiograph the patient should be aligned with the cassette, and extend and tape the head back out of the field of view. The posterior ribs have an extreme downward projection as well as the clavicles. The tube will have to be angled cephalic so that no more than 1 inch of the apices are projected above the clavicles. Corrections for this poor radiograph include: placing the shoulders flush with the cassette and equal distance, tape the head back in extension, align patient with the cassette, use collimation, remove surface foreign bodies, and angle the CR cephalic. In some cases where the frontal view does not demonstrate the entire chest a lateral radiograph may be recommended by the radiologist.

Radiograph #21

image021 This patient was brought to a local emergency room following a motor vehicle accident. There were decreased breath sounds bilaterally and the patient was intubated at the scene. After seeing this portable radiograph taken in the emergency room, what could have been done to make this a better radiograph?

Critique of Radiograph #21

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When you discover a pneumothorax of this proportion make sure the emergency room physician or radiologist looks at the radiograph immediately. The right lung is deflated (yellow arrows) and a significant amount of air is seen in the pleural space. There is no free air in the subcutaneous tissues. A tension pneumothorax is a life-threatening condition caused by air in the pleural space. It causes compression of the lung, heart, and other mediastinal structures, which appear shifted from the midline. This radiograph will obviously be repeated; however, it may be requested after a chest tube is placed to reduce chest tension from the pneumothorax. As for film quality, we see both left lung is partially clipped and the chest is grossly rotated to the left. The trachea should be in the midline to evaluate expansion of the pneumothorax. Also, there appears to be fluid in the left lung, which should be evaluated apart from the heart shadow cast over it. The exposure technique is good, but there appears to be slight under penetration of the left lateral lung field.

Radiograph #22

image022 This radiograph is a follow up portable chest x-ray to evaluate fluid levels in the lungs and a healing pneumothorax. Does this radiograph meet diagnostic standards for the portable AP chest radiograph?

Critique of Radiograph #22

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There is mild rotation of the chest; however the trachea lies anatomically in the midline. There is slight rotation to the right, which is acceptable since serial radiograph may be performed over several days. Whatt makes this radiograph unacceptable is the poor penetration of the lungs as the thoracic vertebral bodies cannot be seen through the heart silhouette. The patient is not centered to the cassette and there are multiple metallic wires within the field that can be moved. This radiograph must be repeated making appropriate changes to include patient centering, positioning in a true upright, shoulders flush with the cassette to reduce rotation, and increase in kVp to better penetrate the lungs. Remove as many of the heart monitor leads as possible so that collimation is possible.

Radiograph #23

image023 Give your critique of this PA upright chest radiograph taken on a young woman of childbearing age?

Critique of Radiograph #23

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There are several good points to this radiograph including that the sternoclavicular joints appear symmetrical, shoulders are depressed with the scapulae slightly superimposing the lateral lung margins. All required anatomy is demonstrated on this upright PA chest radiograph. The patientís inspiratory effort is good as is the exposure technique. The patientís hands are clearly not on the hips with the shoulders depressed and elbows rolled toward the image receptor. As a result there is unnecessary exposure to the arms. On women of childbearing age a lead shield (right photograph) should always be used (represented by the blue shape) to shield the abdomen. Of course close collimation, which is just as important as shielding, should always be applied. The yellow box on radiograph represents the area of collimation that should appear on the radiograph. What should be included are the apices, lateral lungs, and costophrenic angles. Repeating this radiograph for these positioning and collimation errors is not in keeping with ALARA.

Radiograph #24

image024 What is your critique of this supine chest radiograph taken on a patient whose chief complaint was difficulty breathing and abdominal pain with distension?

Critique of Radiograph #24

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There are several aspects of this radiograph that do not meet diagnostic standards including being supine rather than upright, clipped apices, and poor inspiration. Supine imaging is reserved for those patients whose condition could be adversely affected if raised to the upright position. Candidates include those on spine precautions, significant trauma, recently resuscitated, hypotensive, some post operative conditions, and so forth. Given a clinical history of distended abdomen (possible bowel obstruction), or worse case scenario a perforated bowel, the upright projection should be made. Part of the evaluation is to look for air-fluid levels in the visualized abdomen, and for air that is not in the bowel (called free air), which may settle beneath the diaphragm when the patient is upright. Being upright would also allow the patient to take a deeper inspiration to expand the lungs. The inferior limit of the right hemidiaphragm (yellow arrow) is seen, but the left hemidiaphragm cannot be determined. This may be due to motion artifact. Perhaps this radiograph should be taken with the cassette turned lengthwise and vertical collimation applied. Repeat radiograph correcting the mentioned errors with the patient upright.

Radiograph #25

image025 What is your critique of this PA upright CXR using the diagnostic criteria for this view?

Critique of Radiograph #25

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What is obviously wrong with this radiograph is that both costophrenic angles are not included. A subtle finding is the position of the clavicles. When positioning for the PA chest projection the shoulders are depressed and the midcoronal plane is parallel to the image receptor. This will project the clavicles horizontal (red dotted line) rather than vertical as is seen on this radiograph. Also, proper positioning will demonstrate only about 1 inch of the apices above the clavicles. Always check to see if a patient will fit on a 14 X 17 lengthwise when you have doubt. To do this place your hands at the level of the costophrenic angles and have them inhale deeply while observing to see if your hands are pushed out of the field of view. Repeat this radiograph using a 14 x 17 inch cassette crosswise, have the patient depress their shoulders and align the midcoronal plane with the image receptor. Exposure technique is adequate for this patient.

Radiograph #26

image0032 Give your critique of this radiograph taken on a young patient who presented to the emergency room with chest pain and shortness of breath?

Critique of Radiograph #26

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This is a radiograph that should have never been taken supine. One reason to perform this radiograph upright is that it allows for the shoulders to be depressed. By doing so at least 1 inch of the apices are projected above the clavicles. Did you notice the small pneumothorax in the left upper lung lobe? When the shoulders are depressed and brought forward this area is better seen. Overall, this is a good radiograph of the chest. There is sufficient inspiration and the patient displays minimal rotation. The exposure technique is adequate for lung tissue and vascular markings.

Radiograph #27

image027 This radiograph was requested on a premature newborn who suffers acute respiratory distress. The purpose for this exam is to check endotracheal tube placement and lungs. Give your critique for this AP portable supine radiograph.

Critique of Radiograph #27

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At first glance this radiograph may appear to be acceptable; however it is not. The main reason this radiograph should be repeated is motion artifact and quantum mottling. Notice that the vascular lung marking are ill defined and the bronchi are not aerated. This is because the exposure was taken either on expiration or patient motion has occurred. Generally, pediatric radiographers know to watch the inspiration indicator on the ventilator rather than the patient so that exposure is made on full inspiration. Because ventilators are different you should ask the respiratory therapist to show you what setting to watch for peak inspiration. When an infant is not on a ventilator the abdomen rises with inspiration and falls with expiration. The other issue is that the head is not straight in anatomic position. This can misrepresent of the location of the tip of the endotracheal tube. Collimation of the part is lacking in all directions. While this critique does not normally reference the absence of a position marker it should be noted that this is a serious breach when imaging infants. Congenital variations such as dextrocardia, situs inversus, and others such as transposition syndromes are diagnosed because of the position markers. The effort to reduce patient exposure by using excessively high kVp and low mAs resulted in a photon starved radiograph that lacks subject detail. Quantum mottle combined with motion artifact makes this a very unacceptable radiograph. Overall, this radiograph should be repeated correcting the points mentioned.

Radiograph #28

image028 What is your critique of this portable supine AP chest radiograph taken to evaluate the ET tube placement and lung parenchyma?

Critique of Radiograph #28

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Obviously there is mild chest rotation, wire artifact, and poor vertical collimation of the chest. Again this is an example of a chest radiograph that should be repeated because of excessive ventilation motion. These three radiographs show why it is important to carefully evaluate ventilated pediatric chest x-rays for motion artifact. On the left is the radiograph being evaluated. The middle radiograph shows the same chest x-ray in black bone window or what is called a positive image (black and whites are reversed). Notice that the lung markings are not seen on the middle radiograph. Compare this to the lung markings seen on the right radiograph. Observe how the lung markings and the heart are well defined on this radiograph. Also observe how motion artifact produces a faint heart shadow and lack of clear lung markings (middle radiograph). Now back to the original radiograph, which is a negative. Does motion artifact now stand out to you? When this radiograph is repeated turn the head to anatomical position, collimate vertically, and make the exposure at peak ventilator inspiration.

Radiograph #29

image029 This radiograph was taken under extreme urgency as the patient was brought in by ambulance for gun shot injury. The technologist took this radiograph while the patient received cardiopulmonary resuscitation. Considering the circumstance, is this an acceptable AP supine portable chest radiograph?

Critique of Radiograph #29

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There are critical scenarios in emergency medicine where the radiographer is called upon to make radiographs while life-support is being administered. Great skill is required to get a good radiograph the first time under these circumstances. Because patient care does not stop for radiographic imaging in these cases, the radiographer has to get the image under less than ideal conditions. What usually suffers is optimal patient positioning. With that in mind, the technologist did an excellent job in providing diagnostic information. An acceptable amount of chest anatomy is demonstrated along with surrounding soft tissue. Bullet fragments can be seen at various locations of the upper torso. The pneumothorax involving the entire right lung is well demonstrated. The chest tube opening superimposes the lateral rib margin and is not so easily seen because the exposure technique displays high contrast. This may be in part to the collapse of the lung and also to a large amount of air in the pleural space. Because the lower thoracic vertebral bodies display sharp edges we know the mAs is too high and the kVp low. Follow-up radiograph should be taken using low contrast imaging.

Radiograph #30

image030 This patient presented to a local emergency room with shortness of breath following a 5K run. She had no previous history of chest pain. Does this radiograph meet the diagnostic criteria for the PA upright chest view?

Critique of Radiograph #30

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In order to properly critique this radiograph (left) the radiograph is inverted to a positive image displayed on the right. By comparing the negative to the positive image the absence of lung markings in the right lung field is obvious. This is because there is a large pneumothorax involving the entire right lung. A high degree of blackness is seen on the right because this is a high contrast exposure. The positive radiograph shows the dark shadow over the mediastinum (white arrow) that extends into the abdomen. A red arrow shows the heart border, which is distinct from the brightness caused by the selected exposure factors. High contrast is cause by using low kVp. Chest radiography requires high kVp to penetrate the mediastinum and give low contrast to the lung tissue. The optimal kVp range for chest imaging is 100 to 130. What makes this a less than optimal radiograph is that midline shift indicating tension peneumothorax is difficult to rule out because the brightness over the mediastinum due to under penetration. When this radiograph is reordered for chest tube placement adjust the exposure to display low contrast using the 50/15 rule.

Radiograph #31

image031 What are your comments and critique of this radiograph taken on a new immigrant who presents with coughing, hemptosis, and chest discomfort? What special precautions should be taken given the patient history?

Critique of Radiograph #31

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This is a good upright PA chest radiograph. We can tell was made upright because of the air level in the right lung (right arrow). This would not be seen if the patient were supine. The clavicles are symmetrical with at least 1 inch of the apices seen above them. The radiographic exposure technique is adequate for air, fluid, bone, and lung parenchyma. There is good penetration of the thoracic spine allowing us to see the medial left lung through the heart silhouette. As for precautions given the patient history the technologist should consider tuberculosis (TB) as a cause for the symptoms in the clinical history. Appropriate precautions include patient wears a mask, technologist should wear a N95 equivalent mask, and the x-ray performed in a room that can be shut down for at least 1 hour following the exam. These precautions are consistent with infection control policies in regards to acid-fast bacillus (AFB) or airborne precautions. This patient proved to have active and chronic TB.

Radiograph #32

image032 This radiograph is part of a follow-up study to go with a CT scan of the chest to evaluate known lung nodules. Does this radiograph meet the diagnostic criteria for the PA chest view?

Critique of Radiograph #32

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Three things make this an unacceptable radiograph: 1) both costophrenic angles are clipped, 2) scapulae superimposes too much of the lungs (yellow arrows), 3) exposure technique displays high contrast. This patient presents with a hypersthenic body type, therefore, the image receptor should be turned crosswise to include the costophrenic angles. Secondly, the shoulders should be depressed and the scapulae rolled forward to move them out of the field of view. The positive radiographic image on the left shows a small nodule in the right lung (blue box) seen superimposed by the scapula. A nodule can have the same density as bone so it is important that the scapula and ribs do not superimpose a known lesion. Using low contrast resolution helps penetrate bone and lung tissues so that nodules are better seen. This radiograph should be repeated correcting the three points discussed.

Radiograph #33

image033 This PA upright chest radiograph was taken on a recent immigrant whose chief complaint was chest discomfort and difficulty breathing. Does this radiograph meet the diagnostic criteria for the PA view?

Critique of Radiograph #33

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Again this is an example of understanding the role the patient history has in patient care and post care activities. This patient has chronic TB, which the technologist reading the history should have taken appropriate pre and post care precautions. These include wearing a N95 mask if you are a direct caretaker and quarantining the room for at least 1 hour if TB is suspected. As for the radiograph, the exposure is adequate although it displays slight high contrast due to pathology. The Otherwise it meets diagnostic criteria for the PA upright view.

Radiograph #34

image0049 Give your critique of this PA upright chest radiograph taken on an ambulatory adult patient having a history of chronic coughing.

Critique of Radiograph #34

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The primary issue with this radiograph is failure to apply standards in keeping with ALARA. Failures include lack of collimation, improper positioning of the lead waist shield and the arms are included in the field of view. It is rare that three factors that reduce patient dose are completely ignored. The arms and lower abdomen should not appear in a properly positioned, well-collimated field. A strap from the lead waist shield is seen in the lower abdomen. Unfortunately, the lead gonadal shield is ineffective because it does not cover the abdomen properly. Shielding alone will not make up for poor collimation. Other aspects of this radiograph are rotation of the chest and the scapulae are not rotated out of the field of view. Chest rotation is identified by the left sternoclavicular joint being projected away from the spine while the right one is projected over the spine. The shoulders are not depressed and rolled forward, which would project the scapulae laterally. This radiograph should not be repeated although it fails for ALARA on shielding, collimation, and having the arms in the exposed field of view.

Radiograph #35

image0051 Critique this PA upright chest radiograph taken on an infant in a pig-o-stat immobilization device. Clinical history includes fever, lethargy, dehydration, evaluate for pneumonia.

Critique of Radiograph #35

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This is a good radiograph in that the head is straight, the arms up, which rolls the scapulae out of the lung fields. When using immobilization with the arms up, the clavicles are usually projected above the apices. This is to be expected and is acceptable for upright imaging of the infant. The exposure technique adequately demonstrates the lung parenchyma and vascular markings. Shielding and collimation is inadequate for imaging the infant in this type of immobilization device because it limits patient movement applied. The area represented by the yellow box is a good collimation standard for this type of radiograph. So, while this is an acceptable radiograph in terms of exposure technique and positioning, it fails to meet the standards expected when practicing ALARA. No radiograph should ever be repeated because of poor collimation or shielding.

Radiograph #36

image0053 Does this AP upright radiograph of a female patient meet the diagnostic criteria? The reason the patient is sitting on a stool is because of chronic knee pain and episodic syncope.

Critique of Radiograph #36

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The patient is in good anatomical position with the head straight. Under the circumstance the AP projection is acceptable. The clavicles are vertical, which allows the apices to be demonstrated. Medially, the sternoclavicular joints are symmetrical without superimposition on the spine. Lead shielding is seen over the lower abdomen in keeping with ALARA. Though this radiograph should not be repeated there are two avoidable errors seen. First, the right arm is down along the lateral plane of the chest within the exposure field of view. Soft tissue overlap from the arm superimposes on the right costophrenic angle. The second point is poor collimation includes portions of both arms and too much of the upper abdomen. Instead, the arms should be abducted away from the body and close collimation applied. This will reduce unnecessary patient exposure, improve subject contrast, and meet requirements of ALARA.

Radiograph #37

image0054 Give your critique of this PA upright chest radiograph taken on a young female patient for possible bronchitis.

Critique of Radiograph #37

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This radiograph does not meet the diagnostic standard due to improper positioning. The chest displays a lordotic presentation, which projects the clavicles above the first rib and the bony thorax projected horizontally. The position marker indicates the patient is standing, so we can assume the x-ray beam is directed horizontally without cephalic anglation. This indicates that the patient is positioned too far away from the image receptor and is leaning into it. To correct improper rib angulations reposition the patient so that the midcoronal plane is parallel with the image receptor. Have the patient bring the hands down to the hips, relax and roll the shoulders towards the image receptor. Relaxing the shoulders depressing the scapulae will bring the clavicles downward. These two changes will project the lungs to their true anatomical position of about 1 inch above the first rib. The reason this radiograph should be repeated is because the patient is not correctly positioned. Another failing seen on this radiograph is poor collimation and no abdominal shielding. The yellow line estimates appropriate the level of vertical collimation in keeping with ALARA. The exposure technique does adequately demonstrate the lungs and vascular markings, and the heart silhouette. The inspiratory effort could be improved by having the patient inhale, exhale, and then inhale before exposure.

Radiograph #38

image0056 Consider this radiograph taken to evaluate possible cause of shortness of breath and chest pain. The ordering physician requested evaluation of the heart, pacemaker leads, and lung fields. Does it meet diagnostic criteria for the PA upright CXR?

Critique of Radiograph #38

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The required anatomy is demonstrated although the chest displays slight rotation to the right. The left sternoclavicular joint is projected over the spine and the right SC joint is projected away from the spine. The left shoulder is asymmetrically elevated relative to the right shoulder, which projects the clavicle more horizontal. The left clavicle obscures the apical lung field and distorts the first and second left ribs. Rotation error seen here does not mandate repeating this view, which is in keeping with ALARA. However, not being able to see the apical region could hide a pheumothorax. Therefore, this radiograph should be repeated. The exposure technique demonstrates the pacemaker and leads very well. The lung parenchyma is well penetrated showing good detail for the vascular lung markings. However, corrections for this radiograph include: 1) depressing both shoulder, roll them forward so they are equal distance and height to the image receptor, 2) reposition the patient to the right so that the CR enters the thoracic vertebrae at T6.

Radiograph #39

image0057 Does this PA chest radiograph meet the diagnostic criteria given a history of chest pain lasting more than 3 hours?

Critique of Radiograph #39

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The cassette was turned crosswise to avoid clipping the lung fields. All required anatomy is demonstrated in correct anatomical position. Exposure adequately penetrates the medial lung fields through the mediastinum. Lung parenchyma is properly displayed with lung markings visible and motion free. Inspiration does not demonstrate at least 10 posterior ribs. This can be corrected by having the person inhale, then exhale, followed by inhaling deeply. Two breaths will allow the patient to take a deeper inspiration in most cases. The chest is not rotated and the lung markings are clearly defined indicating no motion artifacts. Overall this is a good radiograph that meets diagnostic standards, although inspiratory effort could have been better. There is no need to repeat this radiograph.

Radiograph #40

image0058 Give your critique by telling what could be done differently to make this a better radiograph?

Critique of Radiograph #40

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In keeping with ALARA this radiograph would not normally be repeated. However, there are several things that could have made this a better radiograph. The most important is that vertical collimation should be limited to the level of the tenth rib. The area between the broken yellow lines indicates the area that should be included on a routine PA/AP chest radiograph. This patient appears to have a slight thoracic scoliosis as the shoulders are depressed and the clavicles vertical. There is minimal rotation of the chest structures caused by anatomical rotation of the mid thoracic spine. The exposure demonstrates good penetration of the lung parenchyma and clearly defined vascular markings. Overall, this is a good radiograph that meets diagnostic criteria, except for collimation benchmark. Radiographs are never repeated because of under collimation because this would result in additional radiation exposure, which is not in keeping with ALARA.

Radiograph #41

image0060 Discuss why this radiograph meets diagnostic criteria for the PA chest radiograph.

Critique of Radiograph #41

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The important criteria for the PA chest radiograph are: 1) include all of the lung fields and surrounding tissues from the apices to the costophrenic angles, 2) demonstrate the lungs without chest rotation evidenced by symmetrical vertical displayed clavicles, 3) scapulae rotated out of the lung field and the arms along the sides out of the field of view, 4) exposure penetrates the lower thoracic spine and medial left chest border while preserving detail vascular lung markings, 5) good collimation vertically and ideally collimation on all four borders. Certainly this radiograph meets all of these criteria, which is what makes this a good radiograph. However, for chest radiography it is preferred that low contrast is displayed with optimal background density. This radiograph shows high contrast in the scapula and mediastinum. An optimal technique would use about a 15% higher kVp to increase densities while preserving low contrast and optimal tissue penetration. Phototiming will cause an appropriate reduction in the mAs as the contrast scale lengthens. This radiograph does not need to be repeated although low contrast is preferred. Abdominal shielding should also be applied.

Radiograph #42

image0061 Consider this PA chest radiograph that does not demonstrate the apices. Tell what should have been done to demonstrate the entire lung fields.

Critique of Radiograph #42

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On the right is the repeated radiograph showing the entire lung fields. The technologist had a difficult time determining the length and width of the patientís lungs. As you can see the technologist had limited cassette length to work with because the patientís lungs are long. It appears the technologist misjudged the lateral width of the lung fields and turned the image receptor crosswise instead of lengthwise. The cassette should be placed about an inch above the shoulders and the width determined by the lateral lung field at maximum inspiration. Placing the hands along the patientís lateral borders during maximum inspiration will determine if the cassette should be turned crosswise. If the lung fields are not within the borders of the lengthwise cassette, then it should be turned crosswise. The repeated radiograph on the left meets the diagnostic criteria for the PA chest radiograph although the costophrenic angles are nearly clipped. The exposure technique shows good lung tissue detail and lung clear lung markings. The lower thoracic spine is well penetrated to demonstrate the left medial lung field. The repeated radiograph meets diagnostic standards for the PA view. These radiographs could have been made with the cassette turned lengthwise.

Radiograph #43

image0063 This radiograph was taken using older film-screen imaging with chemical film processing. Discuss why this is not a diagnostic radiograph and what may be the cause(s) of the poor image quality seen.

Critique of Radiograph #43

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Most factors related to patient positioning are correct. For example the patient is upright and the sternoclavicular joints are nearly symmetrical indicating the chest is minimally rotated. The patient is not optimally centered, but no required anatomy is omitted. The shoulders are modestly depressed although the clavicles are not vertical enough to display at least 1-inch of the lung apices above them. But what makes this a non-diagnostic radiograph is that the film is obviously fogged. There are several reasons a film may exhibit fog including overexposure, over penetration of the part, or darkroom type error. In this case the film is unevenly fogged in all areas of the image indicating it was caused by a light leak. The amount of fog is significant enough to warrant repeating this view. But before loading another cassette the technologist should test the film bend to determine if the replacement film is also exposed. The cassette used to make this exposure should also be examined for wear, such as bad hinges that may allow light to enter. When this radiograph is repeated the technologist should be sure to align the coronal plane with the image receptor, depress the shoulders so that the apical region is demonstrated, and center the midsagittal plane with the cassette.

Radiograph #44

image0064 This PA upright chest radiograph was taken on a young patient whose history included bronchitis. Discuss why this radiograph does not meet diagnostic criteria, and state what corrections are needed to make this an acceptable radiograph?

Critique of Radiograph #44

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Two concerns about this radiograph are the costophrenic angles are clipped, and the left clavicle is horizontal, which obscures the left apical lung region. The selection of cassette position can be crucial to including the entire lung fields of most patients. Remember, the hypersthenic person is short and wide. This type will require the cassette to be placed crosswise. The asthenic and sthenic types have long narrow lungs requiring the cassette to be positioned lengthwise. To check the transverse margins place your hands on the patientís lateral margins at the level of the costophrenic angles. Have the patient take in a deep breath, which will expand the lungs. If your hands are still within the cassette boundaries the cassette is correctly aligned. Doing this will reduce the chances of repeating the PA projection as seen in this example. Remember from radiograph 26 there was an apical pneumothorax, which would be missed in some individuals when the clavicles obscure the apices. Always rehearse breathing with the patient do be sure the shoulders remain depressed and that the clavicles remain vertical. Unfortunately, this radiograph should be repeated because of positioning errors.

Radiograph #45

image0066 This radiologist returned this radiograph as non-diagnostic. Discuss why this is not a diagnostic radiograph and tell what should be done to make it acceptable.

Critique of Radiograph #45

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There are several things with this radiograph that do not meet diagnostic standards. Mainly, the exposure technique does not demonstrate the lungs adequately, grid lines obscure viewing, the cassette should be turned lengthwise, inadequate subject detail caused by insufficient mAs, and lack of collimation in keeping with ALARA. On the right is a magnified portion of the right upper lung field to illustrate some of these findings. The grid lines can be clearly seen on the magnified image, which is caused by the reciprocating Bucky not being turned on or a stationary grid with a low grid ratio being used. The radiograph also shows quantum mottling, which is clearly identified by looking at the scapula and areas indicated by the yellow arrows. This is caused by high kVp and extremely low mAs. This radiograph displays low contrast, which is desirable in chest imaging; however, too little mAs is also problematic. Notice the scapula is barely visible because the quantity of radiation used is too low. The other problem with this radiograph is failure to collimate the arms out of the field of view. Turning the cassette crosswise causes automated collimation devices to under collimate to the body part. This can be corrected by turning the cassette lengthwise and bringing the arms up and outward. Correct exposure by decreasing kVp and increasing the mAs using the 50/15 rule. Other corrections include turning the reciprocating Bucky on, and apply collimation in keeping with ALARA.

Radiograph #46

image0068 Discuss why this radiograph is unacceptable and what could be done so that this mistake does not happen routinely.

Critique of Radiograph #46

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The mottled artifact seen on this radiograph is a heating pad placed under the patient. Often artifacts such as a heating pad, cooling pad, spine board, radiopaque patterns on garments and the like can be a cause of repeat imaging. One should always check carefully for potential artifacts. Unfortunately, this radiograph must be repeated. There is also mild rotation of the part as the left sternoclavicular joint is projected away from the spine and the sternoclavicular joint overlies the spine. Rotate the patient slightly to the left to correct positioning. This also appears to be a high contrast radiograph, as the left costophrenic angle is not fully penetrated, neither is the medial left lung border seen. Increasing the kVp appropriately will also improve this radiograph.

Radiograph #47

image0069 This PA upright chest radiograph taken on an infant immobilized in a pig-o-stat apparatus. What should be done to reduce patient dose in keeping with ALARA?

Critique of Radiograph #47

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This radiograph is under penetrated; however, it does not need to be repeated unless the lateral view is flawed. It is desirable that the lower thoracic spine is visible through the heart silhouette. When taken together with a lateral view the unseen medial and anterior portions of the lung will be entirely visualized. Poor collimation is the main criterion that was not met. A dotted broken box indicates the collimation area that would be in keeping with ALARA. Unfortunately, radiographs that meet diagnostic standards are not repeated because of poor collimation as this would add additional dose. Wide collimation was applied in this case because the immobilization brackets are too large for this patient. Always change the brackets to the appropriate size of the infant. This will reduce movement within the immobilization device so better collimation can be applied.


Summary: Critique of the AP/PA chest view
  • Patient preparation includes removal of all metallic objects in the chest field including necklaces, body piercings, and clothing with metal or heavy prints.
  • Chest radiographs should be taken with the patient upright unless conditions do not safely permit it.
  • A horizontal beam demonstrates fluid levels in the chest; therefore, the CR is perpendicular to the MSP.
  • The PA/AP upright chest radiograph is taken at 72Ē SID to reduce magnification of the heart silhouette.
  • The portable AP chest radiograph is routinely taken at 40-44í SID.
  • Exposure is taken on deep inspiration filling the trachea and lungs.
  • At least 10 posterior and 8 anterior ribs should be demonstrated with optimal inspiration.
  • The sternoclaviclar joints should be symmetrically displayed without rotation. The apices and costophrenic angles must be entirely included. The scapulae should be rotated out of the thorax.
  • Exposure should demonstrate good penetration of the lung fields with visualization of lung markings. The medial lung borders should be seen through the heart silhouette without burn out of the lung parenchyma.

Always ask, ďDid I achieve the diagnostic criteria for this view?Ē






Left Lateral Chest Radiograph

The lateral chest radiograph is taken erect with the left side against the image receptor. The left lateral reduces heart magnification as compared to the right lateral. Keep in mind that the side closest to the image receptor is best demonstrated. Although in theory the right lateral is preferred when right lung pathology is of interest, the left lateral is almost exclusively performed in all scenarios. A horizontal x-ray beam allows for distinguishing fluid levels in the chest. The importance of the lateral chest radiograph is that it complements the AP or PA radiograph by providing 90-degree views of the chest. Anterior to posterior viewing of both lung fields is demonstrated. The lateral perspective shows structures such as the anterior and posterior mediastinum, medial lung fields, and costophrenic angles, as well as the thoracic spine. Along with the frontal view, the lateral view allows for a more accurate quantification of fluid when present, extent of disease, measurement of pathology (e.g. nodule, mass), and anterior to posterior viewing of the chest. Therefore, when requested, the technologist should make every effort to include the lateral chest view though this can be very difficult for some patients. The lateral chest radiograph should demonstrate clear lung markings and those structures labeled on the radiograph below:

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Structures that should be demonstrated on the left lateral chest radiograph include: esophagus (A), trachea (B), lung hili (C), heart silhouette (D), lung apices (E), scapulae (F), thoracic vertebra (G), thoracic intervertebral foramen (H), superimposed posterior ribs (I), costophrenic angles (J), and diaphragm (yellow arrows).




Diagnostic Criteria for the Lateral Chest Radiograph


Diagnostic Criteria for the Lateral Chest Radiograph
  • All potential foreign objects such as necklaces, body piercings, bra, sequins, and some fashion printed shirts that can cause an artifact should be removed. Heart monitor leads, intravenous lines and such that can be moved out of the main lung fields should be displaced.
  • The patient should stand flush with the floor so that the midsagittal plane is parallel with the image receptor. There should be no appreciable OID between the chest and image receptor. The arms are raised vertically so that the humeri do not superimpose the anterior chest.
  • The CR should enter the chest at the level of T7 and always horizontal to the floor to demonstrate air/fluid levels.
  • A 72-inch SID should always be used since this decreases magnification of the heart silhouette. Although most portable or recumbent lateral chest projections are performed at 40 to 60 inches SID.
  • High kVp (100 to 140) to produce a low contrast image that properly penetrates the lungs and mediastinum is preferred. A properly exposed radiograph will demonstrate the vascular lung marking and slight visualization the thoracic vertebral bodies through the heart shadow. Plural effusion and other pathologies may obstruct visualization of lung markings compared to the erect position.
  • The radiograph is taken on deep inspiration filling the trachea and lungs. Exposure is taken on suspended inspiration demonstrating a motion free image with clear vascular lung markings. Full inspiration will demonstrate the eleventh thoracic vertebra superimposed on the lung.
  • The chest should not be rotated evidenced by superimposed posterior ribs and costophrenic angles. The sternum should be seen without rotation or superimposition of the anterior mediastinum. Scoliosis may cause the anterior ribs to be superimposed while the posterior ribs are separated at various levels. An adult lateral chest radiograph showing separation of more than 0.5 inch of the posterior ribs should be repeated.
  • A position marker, which is usually an arrow indicating upright and an anatomical marker to indicate left or right side, must appear on the radiograph

Radiograph #48

image036 What is your critique of this radiograph taken to compliment the PA projection? Patient history includes chest pain and shortness of breath.

Critique of Radiograph #48

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This is a good radiograph in that the both lungs are superimposed with minimal posterior rotation of the ribs. The posterior ribs are separated by less than 0.5 inch (1 cm), which is within acceptable limits. The sternum appears free of the anterior lung shadow. The apices are seen without superimposition of the humeri or scapulae. The arms are well extended above the head with the chin extended so it does not rest on the anterior chest wall. The contour of the diaphragm is well demonstrated, and the costophrenic angles are entirely included. All required anatomy is seen with good subject detail. The exposure shows low contrast with good inspiration on suspended breathing. This radiograph is free of motion artifact demonstrating the thoracic vertebrae and their spacing adequately.

Radiograph #49

image037 Does this radiograph meet the diagnostic criteria for the left lateral chest view? If not, then tell what should be done to correct it.

Critique of Radiograph #49

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This radiograph should be repeated for two main reasons, 1) the chest shows excessive rotation, and 2) the costophrenic angles are clipped. Excessive rotation is determined by separation of the posterior ribs greater than 0.5 inch (1 cm). To correct this rotation error the patient should be aligned so that the midsagittal plane is parallel with the image receptor and the arms extended vertically. When upright, fluid collects in the pleural space around the costophrenic angles; therefore, the costophrenic angles must be included on all lateral chest radiographs. Inspiration shows well expanded lung fields free of motion artifact. Exposure technique shows good detailed visualization of the lung markings and lung parenchyma. The heart and mediastinal structures are well demarcated. Overall, the exposure adequately demonstrates chest structures. This radiograph should be repeated because of the positioning errors mentioned.

Radiograph #50

image038 Does this left lateral chest radiograph taken on an elderly person for chest pain meet the diagnostic criteria for this view? The patient is unable to stand so the technologist raised the gurney to a near upright position.

Critique of Radiograph #50

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The technologist did a good job getting the patient nearly upright. What is also good is that the patient is in a true lateral position evidenced by superimposition of the posterior ribs. The sternal borders are demonstrated without rotation. The arms are positioned well above the apices so that this area is seen without superimposed humeri shadows. Good collimation of the part is also seen. The exposure technique shows excellent penetration of the lungs and mediastinum. Good inspiratory effort is seen as the lungs superimpose the lower thoracic vertebrae. There is no visible motion and lung markings are very clear. This is an excellent radiograph that demonstrates good positioning and good follow through on breathing instructions by the patient.

Radiograph #51

image039 Does this left lateral chest radiograph taken on an elderly patient with a history of heart surgery, shortness of breath, and weakness meet the diagnostic criteria?

Critique of Radiograph #51

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Yes this radiograph does meet the diagnostic criteria for the left lateral view. Consider that the patient is on a gurney and the back has been raised to support the patient. The arms are raised well above the apices and the lungs are laterally positioned and superimposed. The costophrenic angles are well seen and superimposed. Radiographic exposure technique adequately penetrates the lungs and bony chest. The thoracic spine and intervertebral spaces are well demonstrated and the sternum is laterally aligned. Note that the patient has sunk into the mattress, which created linear artifacts along the posterior border of the chest wall. It is a good idea to place a radiolucent sponge between the patient and the mattress to avoid this. Overall this has not diminished the diagnostic value of this radiograph. No collimation was used; however, this is not as great a concern because the patient is out of reproductive age. But in keeping with ALARA, always use close collimation that does not clip the lungs, chest wall, or soft tissues.

Radiograph #52

image040 This child was brought to the emergency room by the parents because of persistent fever, coughing, and would not eat. The physician requested PA/Lat views of the chest to evaluate for pneumonia. Does this left lateral view meet the diagnostic criteria?

Critique of Radiograph #52

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Whenever possible an immobilization device such as a pig-o-stat should be used when imaging infants and small children. Immobilization devices can reduce excessive motion that causes repeat imaging and radiation dose. The child in this example is in an immobilization device with the arms and chin properly raised away from the chest. However, the device is not properly sized to the patient as there is slumping at the thoracolumbar junction. It is important that the enclosure brackets are properly sized to the patient to minimize free movement. Nevertheless the patient is in a true lateral position evidenced by the alignment of the spinous processes and sternum. The exposure was taken on expiration, as the lower thoracic vertebrae are not superimposed by the costophrenic angles. Patient motion and improper inspiration are the two most common reasons for repeating infant chest radiographs. The other factor with this radiograph is lack of collimation. The area in the yellow box represents proper collimation. The exposure technique is adequate for this view. So the only reason this radiograph should be repeated is that it was taken on expiration.

Radiograph #53

image041 PA/Lateral chest radiographs were performed on this patient with a history of chest mass and pleural effusions. Does this radiograph meet the diagnostic criteria for the left lateral chest radiograph?

Critique of Radiograph #53

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This radiograph does not meet the diagnostic standards for the lateral chest radiograph. The main reasons are that the anterior chest is clipped, soft tissue of the humeri overshadows the apices, there is slight rotation, the chest is magnified, and the exposure shows underpenetration of the chest. Elevating the patient to a true upright position on the gurney will position the chest within the boundaries of the image receptor. This may require the technologist to first position the patient upward towards the head end of the bed before raising it. Then place a radiolucent sponge behind the patientís back will also help in aligning the chest vertically. The most probable cause for magnification of the chest is increased OID. This patient is sitting upright in the middle of the gurney, which is the cause of the increased OID. Position the patient closer to the image receptor, more upright, and be sure to use at least 72 inches SID. The patient appears to be slightly rotated, but is not evident because of underpenetration.

Radiograph #54

image042 This lateral radiograph was taken on a patient with a history of chronic intermittent coughing. The patient has a history of smoking 2-packs of cigarettes daily and known to have mild COPD. Does this radiograph meet the diagnostic criteria for the lateral chest view?

Critique of Radiograph #54

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The main reason this radiograph should be repeated is it is excessively rotated. The posterior ribs are separated by more than 0.5 inch, which is the upper limit of acceptable rotation. The sternum is also seen superimposing part of the anterior mediastinum. To correct the rotation seen on this radiograph the patient should stand flush with the floor so that the midsagittal plane is parallel with the image receptor. The right costophrenic angle, which is furthest from the image receptor, appears magnified. The inferior heart shadow is projected into the anterior lung field near the sternum. To correct rotation seen on this radiograph rotate the right chest anteriorly until the midsagittal plane is parallel with the image receptor. The exposure technique shows good penetration of the lungs. Inspiration is good showing the lungs expanded over the lower thoracic vertebrae. Lung markings are clear, as the chest is free of motion artifact. Collimation should be applied when this radiograph is repeated.

Radiograph #55

image043 This is a follow up radiograph taken to monitor treatment of this patientís lung pathology. Consider that a thoracenthesis was performed two days prior to this radiograph. Discuss whether the chest is rotated or does the patient suffer scoliosis in your answer.

Critique of Radiograph #55

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Clearly the chest is rotated, as the posterior ribs are not superimposed; neither are the anterior ribs or sternum superimposed. It is difficult to say with certainty that this person does not suffer scoliosis. With true scoliosis the anterior ribs will be superimposed along with the sternum and the posterior ribs having varying amounts of separation. So by looking at this radiograph our best guess is that the patient is positionally rotated and there is mild scoliosis contributing to the chest presentation. Overall, the posterior ribs are rotated more than 0.5 inch, which is unacceptable. The patient is also tilted laterally giving the posterior lung fields a spread appearance. The exposure adequately differentiates lung parenchyma, fluid, and air within the lungs.

Radiograph #56

image044 Should the radiographer approve this radiograph although the arms are down? Consider that the arms are well penetrated and this lateral lung projection seems to demonstrate all needed anatomy.

Critique of Radiograph #56

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This is a case of a patient getting tired of holding their arms up and lowered them. Always set you exposure technique before you position the patient. Make sure that when you approach the control panel to make an exposure that the patient does not have to wait for you to set the exposure technique. Some patients are too sick or too elderly to cooperate more than a few seconds. Also, for safety reasons it is imperative that your focus is on the patient at all times. There is a slight bit of motion seen on this radiograph, which is also a reason to repeat it. The radiograph would have been acceptable for image quality and positioning although posterior ribs are slightly rotated and the sternum is not in a true lateral. Unfortunately, this radiograph must be repeated with the patientís arms raised. Use a faster exposure time to reduce motion artifact that currently blurs the lung markings.

Radiograph #57

image045 Give your critique of this radiograph, discuss what follow through should the technologist make considering the patientís chief complaint is acute onset abdominal pain without any prior surgeries or medical procedures?

Critique of Radiograph #57

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This radiograph shows mild rotation of the chest, but is within acceptable limits. The exposure technique shows well penetrated lung fields with adequate density. All required anatomy is displayed. The central theme of this radiograph is the obvious free air seen beneath the diaphragm bilaterally. Keep in mind the patientís chief complaint was abdominal pain with no history of surgery or invasive procedure. This study should be brought to the attention of a radiologist immediately. This could represent a medical emergency, which should be attended to immediately. This is one of several pathologies every technologist should recognize so as to not handle post processing of radiological information in a sluggish way. A newly found pneumothorax, liver and splenic lacerations, skull fracture, etc. are examples of conditions to alert the radiologist when seen on a radiograph for ďstatĒ reading.

Radiograph #58

image0073 This patient presented with shortness of breath and low oxygen saturation (96%). Give your critique of this lateral chest radiograph.

Critique of Radiograph #58

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The patient is properly positioned within the alignment field. The chest shows mild rotation, but is within acceptable limits. Inspiration is full as the lungs cover the lower thoracic vertebrae. Unfortunately, this radiograph should be repeated due to under penetration of the lung fields, and the humeri soft tissue superimposes the apical lung fields. The patient is holding on to an arm bar to help keep the arms up. Have the patient raise the arms vertical above the head rather than in front of the chest. This will expose the anterior chest and apical region. The kVp exposure should be increased by at least 15% using the 50/15 rule. It may also be necessary to increase the mAs using the phototimer to plus one (+1) or plus 2 (+2) density setting for optimal contrast and density.

Radiograph #59

image0074 Discuss why this radiograph meets the diagnostic standards for the lateral chest view, but does not meet the standard of ALARA.

Critique of Radiograph #59

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This radiograph does meet diagnostic standards because all required anatomy is entirely included, positioning is excellent, and the exposure technique is optimal. However, using good collimation to reduce exposure to the breast and ovaries was not applied. Good collimation that does not omit required anatomy for diagnostic purpose is a standard in keeping with ALARA. In all fairness, the technologist did attempt to shield this patient; however, the shield is improperly placed. It remains in the position used for the PA projection and should have been rotated laterally to protect the abdomen. While shielding is always advised, it is also prudent to use collimation as another layer of protection in keeping with ALARA. Collimation limits the area of tissue exposed, whereas shielding reduces dose to the exposed tissue under the shielding. No radiograph should ever be repeated because of failure to collimate or provide lead shielding, as that practice would increase unnecessary exposure to the patient. Be careful to align radiation shields and collimate to the area of interest.

Radiograph #60

image0075 Give your critique of this left lateral chest radiograph taken on an infant without the use of an immobilization device to restrict movement during the procedure.

Critique of Radiograph #60

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This is a good radiograph in which the patient is properly positioned in a true lateral with the arms raised to demonstrate the apical lung region. The child is in a pig-o-stat apparatus; however the Plexiglas enclosures are not being used. This allows the child to squirm within the immobilizer so that the technologist is unable to apply close collimation. Failure to use the appropriate bracket can be a cause of repeat imaging and poor collimation. Always take the time to select the appropriate bracket size components and use close collimation. Notice the abdomen shield seen at the bottom of the radiograph is insufficient for the routine practice of ALARA. Therefore, you should use collimation as the primary way to reduce patient exposure. Because this radiograph shows good positioning, proper exposure, good inspiration, and clear lung markings this is an acceptable radiograph that meets diagnostic criteria.

Radiograph #61

image0080 This infant chest radiograph was taken given a clinical history of fever and diarrhea. Does this left lateral chest radiograph meet the diagnostic criteria?

Critique of Radiograph #61

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This left lateral chest radiograph shows good positioning of the patient. In this case no immobilization device was used to restrict patient movement. The technologist used an open collimator to be certain to get the chest on the film. Unfortunately this resulted in a large area including the skull and abdomen being exposed. It is also unfortunate that this radiograph was taken on expiration. The lungs do not superimpose the lower thoracic vertebrae, which is how inspiratory effort is determined on the lateral chest radiograph. When it comes to pediatric x-ray imaging we apply ALARA in as strict of terms as we can. With that said, we should check this radiograph with the PA view with a radiologist to determine if it should be repeated for poor inspiration.

Radiograph #62

image0082 This upright lateral chest radiograph was taken on a patient with known congestive heart failure. The ordering physician wanted an in department AP/PA and lateral chest views. Does this radiograph meet the diagnostic criteria for the left lateral chest view?

Critique of Radiograph #62

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This radiograph does not meet the diagnostic standards because it is underpenetrated. This is an obese patient with a body mass index greater than 30. A pacemaker is also seen on the anterior chest wall. We can conclude that the patient was unable to stand so the technologist raised the patient to an upright position in the bed. The positioning of the patient seems to be acceptable as the posterior ribs are superimposed. The inspiratory effort is good based on the number of lower thoracic vertebrae displayed. No collimation was applied since the angle of the patient uses most of the imaging area. The main reason this radiograph should be repeated is that it is under penetrated. Increase the kVp by at least 15% to compensate for the dense pleural effusion seen on this radiograph. Alternatively, increase the phototimer density to +1 or +2 to add radiographic density.

Radiograph #63

image0083 Give your critique of this left lateral chest radiograph taken on a small child with a clinical history or fever, lethargy, and irritable.

Critique of Radiograph #63

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This is a very good radiograph taken with the child in an immobilization apparatus in which the brackets are correctly sized. Notice that all required anatomy is demonstrated without rotation of the chest. The spinous processes can be see laterally aligned and the deep inspiration demonstrates the intervertebral spaces of the lower thoracic vertebrae. The lung markings are clearly seen indicating the exposure time was correctly shortened to prevent motion artifact. This is an excellent radiograph that shows good collimation, proper exposure factors, and patient alignment.

Radiograph #64

image0084 This left lateral chest radiograph was taken on a patient who is suffering syncope and shortness of breath. The ordering physician wanted to check the pacemaker leads as well as to evaluate heart and lungs. Does this radiograph meet the diagnostic criteria for the lateral chest view?

Critique of Radiograph #64

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This is an excellently made left lateral chest radiograph that meets all diagnostic criteria and the specific criteria of the requesting physician. The anterior and posterior ribs are superimposed with minimal rotation. The inspiration is good, and all required chest anatomy is demonstrated. The exposure shows clear lung markings and motion free detail about the pacemaker leads. The arms are well above the apices with no overlap of the humeri soft tissues in the chest. The lungs are well expanded to demonstrate the intervertebral spaces of the lower thoracic vertebrae. The exposure technique penetrates both lung fields without burnout of the lung parenchyma. The technologist obviously used the fastest exposure time possible to get a motion free radiograph. Often the technologist uses preset exposure factors; however, in this case increasing the milliamperage (mA) produced still heart motion to meet the specific diagnostic criteria of the ordering physician. Excellent radiograph!

Radiograph #65

image0085 Consider this radiograph of a small child taken to rule out pneumonia. Does this radiograph meet the standards for the left lateral chest view and for ALARA?
Critique of Radiograph #65

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It is important to always use the correctly sized immobilization brackets because this will allow for proper positioning and close collimation. This is an example of failure to appropriately collimate to the area of interest. The entire abdomen is included in the field of view, and there is no gonadal shielding which is not in keeping with ALARA. The area in the dotted yellow box represents what would be considered optimal collimation. Notice that the upper ribs are superimposed, but the lower ribs are rotated slightly. This amount of rotation does not require repeating the projection. The inspiratory volume is adequate but not optimal. Proper inspiration on the lateral view will demonstrate lungs superimposing the eleventh thoracic vertebra. Overall, this is an acceptable radiograph that does not need to be repeated, but does not meet the standards for shielding and collimation. The exposure does penetrate the thoracic vertebrae and demonstrates the lung marking clearly. The most common reason for repeating pediatric chest radiographs is patient motion. The most common breach in ALARA is poor collimation and/or gonadal shielding.

Summary: Critique of the lateral chest view

  • Have the patient take in a deep inspiration filling the trachea and lungs.
  • All chest radiographs should be made with the patient upright unless circumstances do not safely permit it.
  • Portable lateral chest on newborns and some pediatric patients may be performed with the patient in either the dorsal or lateral recumbent position.
  • The CR should be perpendicular to the mid coronal plane. Images should be taken 72Ē SID to decrease magnification of the heart silhouette.
  • Both costophrenic angles should be superimposed. The anterior, posterior, superior and middle mediastinal areas should all be entirely included on the radiograph. The chest should not be rotated evidenced by two finger breadths between the posterior ribs or costophrenic angles (this is equivalent to rotation of no more than 0.5 inch).
  • All metallic objects that may cause an artifact, such as necklaces, body piercing, metallic buttons, pen or pencil in shirt pockets should be removed.
  • Both arms should be raised vertically so that the humeri do no to shadow the lung fields.
  • Always indicate with a lead marker the anatomical left or right side of the patient.
  • A marker such as an arrow indicating upright, supine, or recumbent should also be used.
  • The date and time of exposure for portable imaging should be indicated on the radiograph to assure chronological comparison of images.
  • Radiographic exposure technique should provide a low contrast image (kVp 100 to 140 kVp is recommended for adults and 80 to 100 kVp for infants and small children). The lung parenchyma, apices, and costophrenic angles should be visualized with good subject contrast.
  • Bring to the attention of the radiologist or attending physician if the radiologist is not available any radiographs that may be a surgical or medical emergency, for example: pneumothorax, hemothorax, subdiaphragmatic free air, etc.
Always ask yourself, "Did I achieve the diagnostic criteria for this view?"




Summary Points