Film Critique - Part 2: Abdomen


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

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

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Film Critique - Part 2 Abdomen and Pelvis

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



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Article Navigation:

Objectives

Introduction

Relevant Anatomy of the Abdomen and Pelvis

Diagnostic Criteria for AP Abdomen Views

Diagnostic Criteria for the Left Lateral Decubitus Abdomen View

Summary Points

References

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Objectives






Introduction

Plain films of the abdomen and pelvis are still commonly performed in most radiology departments. Many acute and chronic disease processes affecting the abdomen may produce plain-film radiographic signs. However, it is not possible with plain-films alone to always establish the correct diagnosis, therefore, it is imperative that these studies are performed correctly as they may indicate the need for further imaging. Intrathoracic pathology can produce symptoms of an upper abdominal process and so a chest radiograph is often obtained as part of the acute abdominal radiographic series. It is important that the technologist include a complete history for the examination as this may indicate to the radiologist additional tests to recommend. Most cases for radiographic imaging present with abdominal pain, indigestion, nausea, vomiting, diarrhea, constipation, injury, fecal incontinence, jaundice, dysuria, urinary frequency, urinary incontinence, and hematuria, blood in stool, weight loss, weight gain, and chronic illnesses among others. Characteristics of the clinical symptoms are also to be noted, for examples, onset and duration, character or quality of symptoms such as sharp or dull pain, and its location or spread. In most clinical settings the anteroposterior (AP) view of the abdomen is taken supine and erect. Specific criteria for imaging the abdomen in the supine, upright, and lateral decubitus positions are the central focus of this critique.






Relevant Anatomy of the Abdomen and Pelvis

To consistently perform proper abdominal radiography it is important that the radiographer maintains an understanding of the anatomy and relationships of structures within the abdominopelvic cavity. In this section we will review some basic anatomy and concepts that are important to abdominal radiography. To help describe the location of symptoms such as pain or pressure, or to locate structures within the abdomen either the four quadrants, or nine quadrants model of the abdomen is used. The four quadrant model is used most commonly in referring to the location of abdominal structures because each quadrant contains relatively distinct structures. The nine quadrant model is more detailed, for example in describing pain, such as epigastric vs. umbilical or inguinal.

The four quadrant model is imagined as two perpendicular lines passing through the abdomen at the umbilicus at right angles to each other. The horizontal line is at the level of the umbilicus, which is about the level of L3 and L4 (3rd and 4th lumbar vertebrae). The vertical plane corresponds with the midsagittal plane, which passes through the umbilicus and the symphysis pubis. The four resulting quadrants are the right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ). Some of the structures found in the right upper quadrant include the liver, duodenum, pylorus, right kidney, hepatic flexure, portions of ascending and part of the transverse colon. The right lower quadrant contains the appendix, cecum, ascending colon, bladder, right ovary, uterus if enlarged, right spermatic cord, and right ureter. The left upper quadrant contains the tip of the medial liver lobe, spleen, stomach, left kidney, pancreas, splenic flexure, and parts of transverse and descending colons. Within the left lower quadrant are the sigmoid colon, descending colon, bladder, and uterus if enlarged, left spermatic cord, and left ureter.

The nine region model uses two horizontal and two vertical planes. The vertical planes are the transpyloric and transtubercular planes. The transpyloric plane is a transverse plane at the level of 1st lumbar vertebra. It is so named because it runs through the pyloric portion of the stomach. The transtubercular plane is at the level of the 5th lumbar vertebra passing through the anterior superior iliac spines (ASIS). Right and left sagittal planes divide the two transverse planes. They are located midway between the midsagittal line and the ASIS on each side of the body. The location of organs within the nine regions is affected by body habitus, age, or patient position. Therefore, the nine regions model is used mainly to describe a patient’s symptoms, for example, epigastric pain or left inguinal hernia. The nine regions from right to left, top to bottom: the right hypochondrium, which is below the right ribs and costal cartilage. The epigastric region is in the upper midline just below the sternum. The left hypochondrium is located just below the left anterior ribs and costal cartilage. Deep within the left hypochondrium the spleen and tail of the pancreas can be found. The right and left lumbar regions are below their respective hypochondrium and represent the area of the flank. Between them is the umbilical region, which is filled mostly by the small intestines. Left and right left inguinal (iliac) regions mark the lower lateral boundaries of the model. The pubic (hypogastric) region lies between the iliac subdivisions and contains the urinary bladder and reproductive organs.

Regional descriptions help the radiographer to understand correlations between clinical diagnostic differentials and radiographic procedures. For example LLQ pain of digestive origin could represent diverticulitis, whereas right flank pain could point towards renal stones. The radiographer should also be familiar with these regions since it will aid in describing the location of patient symptoms when the technologist does their patient assessment. All requisitions for x-ray imaging should indicate appropriate clinical history either by the clinician or briefly by the technologist.

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This table of the four quadrant model of the abdomen lists some of the structures in their respective quadrants. Keep in mind that some structures will vary according to body habitus or normal anatomical variation. Structures are also described as being intraperitoneal, retroperitoneal, or infraperitoneal.
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These two radiographs are divided into the 4 quadrant model (left) and 9 regions model (right). The four quadrant model shows the right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ). The nine regions are labeled: 1) right hypochondrium, 2) epigastric, 3) left hypochondrium, 4) right lumbar (lateral), 5) umbilical, 6) left lumbar (lateral), 7 right inguinal (iliac), 8) hypogastric (pubic), 9) left inguinal (iliac).

Various organ systems are seen in limited detail on the plain-film radiograph of the abdomen and pelvis. Each of these organs will be briefly discussed; however, keep in mind that the plain film flat and upright radiographs while are diagnostic tools for evaluating the abdomen, they are also a survey type study. Specific details about structures within the abdomen can be seen using special imaging techniques that go beyond the plain-film studies. For example, a procedure called an upper G.I (gastrointestinal) study can visualize the stomach. Likewise, a procedure called a barium enema (BE) visualizes the large intestines, and an intravenous pyelogram visualizes the kidneys and renal system. This discussion of plain-film radiographs of the abdomen considers those conditions that can be diagnosed with plain films. Most structures of the abdomen can be seen radiographically. For example, organs of the digestive system, hepatobiliary system, circulatory system, urinary system, reproductive system, and fat can be seen using various imaging modalities. Some involve the use of ionizing radiation; other may use ultrasound, magnetic resonance imaging, or nuclear imaging techniques. Accessory organs of digestion such as the liver, gallbladder, and spleen can be limitedly visualized on plain films. But regardless of the anatomy, there are important relationships between anatomical structures that must be seen on a well-made radiograph of the abdomen. To appreciate the importance of the plain-film radiograph it is necessary to review some basic anatomy, and at times comparing plain-films to other imaging modalities like computed tomography.

When imaging the abdomen it may be necessary for the radiographer to locate certain topographical landmarks by palpating. It is important to inform the patient of the purpose of palpating landmarks and when one is about to perform palpation. There are seven palpable landmarks of the abdomen used to position a patient for imaging. Some landmarks are more difficult to locate than others and depend on the presentation of the patient, for example, being thin or grossly obese. The seven landmarks are: 1) xiphoid tip, inferior costal margin, 3) iliac crest, 4) anterior superior iliac spine (ASIS), 5) greater trochanter, 6) symphysis pubis, 7) ischial tuberosity. These landmarks are referenced to their vertebral levels where certain abdominal structures can be localized.

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These two 3D CT images demonstrate the seven topographical landmarks of the abdomen and pelvis. The left CT image shows the densely muscular anterior and lateral walls of the abdomen. Labeled on these CT images are: 1) xiphoid tip, inferior costal margin, 3) iliac crest, 4) anterior superior iliac spine (ASIS), 5) greater trochanter, 6) symphysis pubis, 7) ischial tuberosity. These landmarks are referenced to their vertebral levels where certain abdominal structures can be localized.

The xiphoid tip is the most distal portion of the sternum and is found at about T9-10 (T = thoracic) vertebrae. It represents the superior margin of the abdomen, though this is highly dependent on body habitus. The inferior costal margin is used to locate the stomach and gallbladder in many individuals approximating L2-L3 (L = lumbar) vertebrae. The most commonly used abdominal landmark is the iliac crest, which is at L4-L5 vertebrae. The importance of this landmark is that it represents the middle of the abdominopelvic cavity. Centering the patient and cassette at the iliac crest will allow the technologist to demonstrate the abdomen. A similar landmark, the ASIS (anterior superior iliac spine) is used to locate pelvic structures and can be used to localize lumbar vertebrae. The greater trochanter is a landmark for the hip and pelvis. By internally rotating the femur one can easily palpate this landmark. The tip of the greater trochanter is about 1 inch above the symphysis pubis and marks the level of the urinary bladder. The inferior margin of the pelvis is found by locating the symphysis pubis. This landmark is sometimes embarrassing for the patient so the greater tuberosity is more often preferred. The ischial tuberosity is the inferior portion of the ischium bone. It marks the inferior limits of the pelvis that should be seen on the AP abdomen radiograph. It marks the rectum portion of the large intestines when a PA projection of the abdomen is needed.

Abdomen radiographs generally include the abdominal and pelvic cavities. The abdominal cavity houses the organs of digestion, mainly the stomach, small intestines, and large intestines. Structures of the hepatobiliary system (liver, gallbladder, and pancreas) are also within the abdominal cavity. It also houses the spleen, which is part of the circulatory system, and the kidneys and ureters from the urinary system. The urinary bladder, part of the intestines, and the female reproductive organs mostly fill the pelvic cavity. The abdominal cavity is not synonymous with the peritoneal cavity. The abdominal cavity houses abdominal viscera that may lie intraperitoneal or retroperitoneal. The muscles of the abdominal wall, the diaphragm, and the pelvic brim limit the abdominopelvic cavity.

The abdominal cavity is lined with a double-layer serous membrane called the peritoneum. The peritoneum is composed of two layers, the parietal and visceral layers. The parietal peritoneum lines the abdominal wall; contains nerves, and is sensitive to pain. Parietal peritoneum pain is described as sharp localizing. Visceral peritoneum, also called the serosa, lines abdominal organs. It is poorly sensitive to pain localization, which is caused by stretching of bowel or mesentery. A thin space called the peritoneal space lies between the two layers. It is a potential space like the pleural space in the lungs and is only visible during pathological states. The peritoneal space contains a small amount of serous fluid to allow the layers of the peritoneum to slide upon each other reducing friction between abdominal structures.

A double reflection of parietal peritoneum called mesentery attaches the bowel to the posterior abdominal wall. Mesentery contains lots of fat, lymph nodes, blood vessels, and nerves to and from the viscera. The root of the mesentery refers to its attachment to the posterior abdominal wall. Most of the bowel is attached by mesentery to the posterior wall. For example, the root of the small intestines is about 15cm long and passes to the left of L2 vertebra, downward and to the right; it contains the superior mesenteric vessels. The mesentery serves two purposes: 1) a conduit for blood vessels and nerves, and to resist twisting of the bowel. A volvulus is a condition in which the bowel twists on its mesentery. This most commonly occurs in the sigmoid or ileocecal areas. Volvulus is an important diagnosis because in some cases the blood supply is pinched off and may cause ischemia, necrosis, and perforation of the bowel. A volvulus can sometimes be seen on plain film as the collection of air conforms to the shape of the dilated bowel segment. The greater omentum is a double fold of peritoneum that is attached to the duodenum, stomach and transverse colon.

What many laypersons call a large stomach in reference to belly fat is really accumulation of fat within the greater omentum. Omentum is a multi-layered fold of peritoneum that extends from the stomach to adjacent organs along the anterior abdomen. The lesser omentum attaches the liver, greater curvature of the stomach and proximal duodenum together. Contained within the lesser omentum are the common bile duct, portal vein, hepatic and gastric vessels. The greater omentum is a large 4-layered fold of peritoneum that hangs from the greater curvature of the stomach down over the transverse colon and covers most of the small intestine. It is medically important because it is migratory tissue that can wall off an intraperitoneal infection or tumor resisting its spread. This is commonly seen, for example, when the appendix ruptures and is contained within an abscess.

Muscles play important roles in abdominal anatomy and too have radiologic significance. The muscles of the abdomen that we will briefly discuss are those of the anterior wall, diaphragm, lateral wall (flank), and psoas. The anterior wall consists of three flat muscles (external, internal oblique and transverse abdominal) and one strap muscle, the rectus. Muscles and aponeuroses act as a corset confining the abdomen and protecting it. The aponeuroses are a two-layered sheet like tendon that covers the abdominal muscles. It is interwoven to cover the rectus muscle forming the rectus sheath and linea alba in the midline. The anterior wall abdominal muscles function in support and protection the abdominal viscera, assist in flexion and twisting of the trunk, and increases intra-abdominal pressure during breathing and defecation. The anterior abdominal muscles also assist in micturition, childbirth, and stabilization of the pelvis during movement.

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The muscles of the anterior wall, internal oblique and rectus abdominis muscles (A) form a muscular shield over the abdomen. The rectus muscles are separated by thin transversely oriented tendinous sheaths (yellow arrow) and layered aponeuroses (B). The lateral wall is formed in part by the external oblique muscle (C). These structures are covered by tendinous fibers of the aponeurosis that connect to the linea alba in the midline. The umbilicus can be seen within the linea alba.

The diaphragm is a large dome shaped muscle that separates the thoracic and abdominal cavities. It is a muscle of respiration that increases and decreases the thoracic diameter during breathing. The diaphragm is important because it has three anatomical openings through which the aorta, inferior vena cava, and esophagus pass. The esophageal hiatus is slightly left of midline at T10 vertebral level. The vagus nerves, esophageal and gastric vessels also pass through the hiatus. The aortic hiatus is posterior to the diaphragm and transmits the aorta, lymphatic vessels, and azygous vessels. Normally the diaphragm is considered impermeable; however, extraluminal air, ascites, pleural effusion, tumor, and pus can pass from the abdomen to the thorax and vice versa. Abdominal structures can sometimes herniate into the thoracic cavity through the three openings. For example, a hiatal hernia is a protrusion of a portion of the stomach through a widened esophageal opening in the diaphragm.

Plain film radiographs can be useful in diagnosing peridiaphragmatic fluid collections. Those that lie above the diaphragm are generally pleural effusions, whereas those below it are generally ascites or an abscess. A perforation of the bowel can release air into the abdominal cavity. This “free air” in the abdomen will collect under the diaphragm when the patient is upright. Several other pathological conditions such as hernias and elevated hemidiaphragm can be evaluated on plain-films when the diaphragm is included on the radiograph. Therefore, a standard protocol at many institutions is to include a PA chest view along with the 2-view abdomen series.

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These two radiographs show the importance of including the diaphragm on the plain-film abdomen x-ray. The coronal 3D CT image on the left shows the left diaphragm (yellow arrows). The PA chest radiograph on the right also shows the diaphragm (yellow arrows). Normally the diaphragm is not clearly visible on the chest x-ray except in pathological states where free intra-abdominal air (blue arrows) collects under it. Notice the right hemidiaphragm is elevated. Normally there is some elevation of the right hemidiaphragm due to the liver.
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Sometimes free intra-abdominal air can be subtle and can only be seen on CT. The yellow arrows on the coronal CT image show small amounts of free-air (yellow arrows) and green arrow on axial CT (right), which is below the diaphragm (blue arrow). Air in the intestine is surrounded by the bowel wall (white arrow) and is not “free.” To see this amount of free air the patient should be upright a minimum of 5 minutes before taking the upright radiograph.

It is also important that the right and left psoas muscles are visualized on the abdomen radiograph. These are large thick muscles located on either side of the lumbar vertebrae. The psoas attaches to the transverse processes and vertebral bodies of all 5 lumbar vertebrae and T12 merging distally with the iliacus muscle to insert on the greater trochanter of the femur. The small thin psoas minor muscle lies anterior to the psoas major and merges with it near the inguinal ligament. Primary functions of the psoas muscles are to flex the hip joint and bend the spine laterally. Several nerves and blood vessels can be found coursing the anterior surface of the psoas muscles. The ureters also lie on the anterior surface of the psoas muscles. The lateral borders of the psoas muscles should be visible on the abdomen radiograph when proper exposure factors are used. Free fluid in the abdomen (outside the peritoneal cavity) such as a retroperitoneal bleed caused by a ruptured aneurysm, dissection, or traumatic aortic injury may present as obliteration of the lateral border of the psoas muscles.

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These two radiographs: left - a coronal CT image, and right - an AP supine radiograph with arrows indicating the psoas muscles. The CT image shows the broad thickness of the muscles at their attachment to the lumbar vertebrae. The radiograph shows the psoas shadow, which is seen when the exposure is correct and the patient suspends breathing. The psoas muscle should be seen on plain-film radiographs of the abdomen.

The flank is an important area of the abdomen that should be demonstrated on the abdomen radiograph. The lateral wall of the flank consists of subcutaneous fat. Intermediate structures include the abdominal oblique muscles with fatty layers between, and extraperitoneal fat. Lining the flank medially is the parietal peritoneum. Of course, the parietal peritoneum is not visible radiographically since it is a thin membrane; however, its location is precisely defined by the medial extraperitoneal fat. The structure of primary radiological interest pertaining to the flank is that radiolucent longitudinal shadow medial to the flank muscles called the flank stripe. Because the medial border of the flank stripe is the parietal peritoneum it can be used to diagnose the thickness of the bowel wall. For example, normally the ascending and descending colons abut against the parietal peritoneum of the flank stripe. This allows the radiologist to estimate the thickness of the bowel wall when gas and fecal material outline the mucosal lining of the bowel. A space between the bowel wall and the flank stripe, called the paracolic gutter, is a potential space that can collect fluid as in ascites and displace the colon. The flank is an important area of the abdomen radiographically; it is important that both lateral abdominal walls are demonstrated on the abdomen radiograph, and that the flank stripe is not over exposed.

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These radiographic images show the anatomy of the flank that should be demonstrated on the plain-film radiograph of the abdomen. The radiograph on the left is a low contrast exposure that shows the flank muscles and their attachments to the ribs and pelvis. On the left is a portion of a coronal CT image that displays better detail about the flank area. Although the muscles of the flank are seen on this x-ray, higher contrast is needed to demonstrate the flank stripe.
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These radiographs demonstrate the radiographic appearance of the soft tissues of the right flank. The extraperitoneal fat produces the sharply defined curved lucent band (open arrows-left radiograph). The lucent shadow of the flank stripe is seen extending from the lateral margin of the liver above to the iliac crest below. Gas and feces help identify the ascending colon and hepatic flexure inferior to the liver margin. The extremely low contrast view of the right flank is seen on the left. High kVp exposure better identifies the muscles of the flank on plain-film but does not display sharp detailed visualization of the lucent shadow of the flank stripes.
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This coronal CT image shows the soft tissues of the flank. The extraperitonel fat produces the lucent shadow of the flank stripe. The drawing on the left labels the structures of the flank: parietal peritoneum (A), extraperitoneal fat (B), transverse abdominis muscle (C), internal oblique muscle (D), external oblique (E), and fatty layers separating the muscle layers (F).

It is also important that the radiographer understands the basic outlay of structures within the abdominal cavity. Within the abdomen parts of the digestive tract can be found in all quadrants. The stomach is generally seen as a gas bubble on plain-film unless distended by fluid or air. Its position and shape can indicate normal anatomy, but when distorted can represent a mass effect such as a tumor. We have already discussed the peritoneum and mesentery that line abdominal structures. Some structures such as the digestive system are anatomically complex having parts that are intraperitoneal and retroperitoneal. All structures within the abdomen are classified as being intraperitoneal, retroperitoneal, or infraperitoneal depending on whether they are covered with visceral peritoneum and whether or not they are attached to mesentery.

The retroperitoneum is especially important because it houses structures between parietal peritoneum and transversalis fascia. Within the retroperitoneum lie the kidneys and proximal ureters, adrenal glands, proximal ureters, pancreas, duodenum, ascending and descending portions of the colon, inferior vena cava, and aorta. Major portions of the larger lymphatic vessels (thoracic duct and cistern chyle), lymphatics, nerves and fat also occupy this space. Traumatic and spontaneous retroperitoneal hemorrhage due to aneurysm or dissection rupture is fairly common. The key point is that retroperitoneal fluid is always a major medical concern as this may represent rupture of a great vessel. It should not be confused with fluid in the peritoneal space (ascites), which is medically significant, but is not immediately life-threatening in most cases. Retroperitoneal lymphadenopathy is also of great concern because of the potential for metastasis along the major lymphatic vessels.

It is important that plain film radiographs are properly exposed since structures are superimposed and relationships are critical to diagnosis. Being able to identify structures to determine if the exposure is correct is part of film critique. Let’s consider the digestive tract, which has parts that are intraperitoneal and retroperitoneal. This is not apparent on plain films but can be seen on specialized exams such as the upper gastrointestinal study (aka upper G.I exam) or the barium enema, or on cross-sectional CT studies.

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These two abdomen radiographs show parts of the digestive tract due to the presence of gas that provides natural contrast in the bowel. Portions of the digestive system are well defined considering that details such as an ulcer or intestinal polyps cannot be seen on plain films. The large intestine lies along the periphery of the abdomen as can be seen by labels: ascending colon (A), descending colon (B), transverse colon (yellow arrows), hepatic flexure (blue arrow), splenic flexure (purple arrow) and sigmoid colon (green arrows). The small intestines lie central in the abdomen. We can see a good portion of the small intestine (C) because a dilute oral contrast solution used for CT imaging provides radiopaque contrast.
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Compare structures seen on the coronal CT image on the left with the plain film AP abdomen radiograph on the right. Some of the important structures to note are the stomach (S) and small intestines, which are outlined by oral contrast (left) on the coronal CT image and air on the plain-film radiograph (yellow arrows). Notice the tip of the liver (blue arrows), which is seen on plain film along the lateral inferior margin of the lower right ribs should be demonstrated on the AP abdomen view.
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The large intestines located primarily along the periphery of the abdomen. The radiograph on the left shows a frontal view of the abdomen from a barium enema study. By comparing the gas filled large intestines on the plain-film radiograph (right) one can see the value of providing good contrast and density on plain film radiographs of the abdomen. Note the splenic flexure (yellow arrows), transverse colon (purple arrows), hepatic flexure (blue arrows), and diverticula seen in the descending and sigmoid colons.
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There are several structures that should be seen on the abdomen radiograph, for example the renal outline (yellow arrow) can give valuable information such as hydronephrosis, renal injury, renal stones, traumatic renal injury, and the like. The renal outline is seen because of perirenal fat that provides radiographic contrast with the proper exposure. The comparison coronal CT image also shows the kidneys (yellow arrow). The spleen (blue arrows) is also of radiographic interest especially in suspected injury or splenomegaly. Exposure contrast and density should show sharp detail of the visualized rib(s) indicated by letter “R” and pelvis. The iliac wing (W) is labeled along with the iliac crest (dotted line), which is a radiologic landmark for centering the abdomen.

Keep in mind that there are many other structures in the abdomen that have not been covered in this brief review. The aorta, venous system, lymphatic system, urinary system structures, spleen, pancreas, and others have not been covered. What we have discussed are those structures that should be seen on the AP abdomen view that will guide the technologist in meeting diagnostic criteria. With this in mind let’s review the basic frontal views of the abdomen commonly taken in radiology.

Anteroposterior Projection

Plain-film abdomen radiographs are usually performed as a survey or scout for imaging procedures, without oral contrast agent. The abdomen is also imaged because of pain, distension, and various other conditions. The frequency of findings on the supine view alone is considered low and nonspecific; however, in cases of severe abdominal pain and suspicion of bowel obstruction or perforation is proven valuable. In addition, abdomen radiographs are commonly used to assess placement of various tubes and catheters. The size of viscera such as the liver, kidneys, or spleen, vascular calcifications, and penetrating trauma and bone fractures can be ascertained in some cases from the plain abdomen and pelvis radiograph.

There are basically three AP views of the abdomen that are routinely taken: The supine or flatplate, upright, and left lateral decubitus. Sometimes only one view of the abdomen is requested such as the supine view. However, in most cases at least a supine and an upright view are taken. The AP abdomen should include from just above the diaphragm down to the ischial tuberosities. Completely demonstrating the obturator foramen insures that the distal field of view is inclusive of the lower abdominopelvic region. For males over the age of 50 including all of the prostate gland is also recommended. Also, the lateral body wall should be included on the radiograph, which may require using two 14 X 17 crosswise exposures to capture the anatomy. The hands, metallic objects, and clothing that can cause artifacts should be removed. Feeding tube, electrocardiogram lead wires and the like should be straightened and pulled out of the field of view. In other words, there should be minimal obstruction of image display by needed patient monitoring devices left in the field of view. Below are additional notes about imaging the abdomen in the supine, upright, or decubitus positions.

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The AP supine projection of the abdomen should include the eleventh thoracic spinous process superiorly and inferiorly the obturator foramen. When these structures are not demonstrated the technologist must decide after viewing all radiographs, what should be repeated to cover all diagnostic criteria. Structures that should be seen include the lateral rib margins (A), the liver especially the tip (B), clear detail bone edges of the lumbar vertebrae (C), gas patterns of the small intestines (D) and large bowel (E-ascending colon) and (F-splenic flexure), flank stripe (G), and iliac crest (H). Other soft tissues of the abdomen that should be seen include the right renal outline (yellow arrows), right renal outline (blue arrows), and stomach (green arrow). Not all parts of the bowel will be seen as this depends on fecal material and air in the gut.
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The AP supine abdomen projection is often taken as part of the trauma series. In all cases the inferior limits of the abdomen for the supine view should include the ischial tuberosity (D) and obturator foramen (F). Other structures of the pelvic region that should be seen include the iliac wing (A), greater trochanter (B), lesser trochanter (C), and symphysis pubis (E). The urinary bladder (yellow arrow) should be seen superimposed on the coccyx (H) and sacrum (G). The psoas muscle shadow (blue arrows) should be seen bilaterally when fecal material does not obstruct viewing.
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The upright radiograph must always demonstrate both hemidiaphragms in order to evaluate diaphragmatic hernias, free-air, or elevated hemidiaphragm. The upright abdomen radiograph will meet diagnostic standards for anatomy demonstrated when the diaphragm is entirely seen, lateral soft tissues of the abdomen, and the iliac wings. It is not necessary to include the entire pelvis since this is a requirement of the supine radiograph. Structures labeled on this radiograph are the diaphragm (green arrows), iliac crest (A), iliac wing (B), right psoas muscle (red arrow), bowel gas (blue arrow), and spinous process of lumbar vertebrae (yellow arrows).





Diagnostic Criteria for the AP Upright Abdomen
  • The AP upright abdomen radiograph is always performed first in a two or three view abdominal series.
  • Patient should be placed in the upright position during transport for a minimum of 5 minutes and ideally 15 minutes prior to imaging.
  • No motion: ribs, diaphragm and gas filled structures show sharpness; the exposure is made on expiration.
  • Diaphragm must be entirely included, unless a PA upright chest radiograph is also taken as part of the abdominal series. The lateral margins of the abdomen must be demonstrated and all lateral soft tissues out to the skin line when penetrating injury is suspected.
  • No rotation evidenced by pelvis and lumbar vertebrae being symmetrical. Specifically, the right and left iliac wings equal in size and shape, and spinous processes in center of vertebrae. The obturator foramina symmetrical and opened.
  • Radiographic exposure should demonstrate low contrast that visualizes the liver and renal margins, psoas muscle outline, lumbar transverse processes, and lower ribs. The exposure should show good contrast between air, muscle, and fat as these tissues may show key diagnostic information.



Diagnostic Criteria for the AP Left Lateral Decubitus Abdomen
  • The left lateral decubitus abdomen radiograph is always performed first in a two view abdominal series.
  • Patient should be placed on their left side in the decubitus position during transport for a minimum of 5 minutes and ideally 15 minutes prior to imaging.
  • The down side, which is the left side of the patient, should be slightly elevated using a hard surface or a radiolucent sponge so that it is included on the radiograph. The entire upside, which is the right side, must be entirely included on the radiograph. The right hemidiaphragm must be entirely demonstrated. Likewise, the lateral boundary over the right pelvis must be entirely included. In a person whose hips are wider than the chest, free-air may accumulate in the area over the right iliac wing rather than under the diaphragm.
  • No motion: ribs, diaphragm and gas filled structures show sharpness; the exposure is made on expiration.
  • No rotation evidenced by pelvis and lumbar vertebrae being symmetrical. Specifically, the right and left iliac wings equal in size and shape, and spinous processes in center of vertebrae.
  • Radiographic exposure should demonstrate low contrast that visualizes the liver and renal margins, psoas muscle outline, lumbar transverse processes, and lower ribs. The exposure should show good contrast between air, muscle, and fat as these tissues may hold key diagnostic information.



Diagnostic Criteria for the AP Supine Abdomen
  • Structures demonstrated variably are the renal outlines, ureters, psoas muscles, liver, spleen, diaphragm, peritoneal fat stripes, bladder, ribs, lumbar vertebrae, and pelvis. The lateral margins to include the entire flanks must be demonstrated.
  • No motion: ribs, diaphragm and gas filled structures show sharpness; the exposure is made on expiration.
  • · Diaphragm must be entirely included if only the supine view is taken. If an upright or decubitus film is also taken then the lower pelvis to include the ischial tuberosities must be seen. Most of the upper abdomen to include from T11 down and including the obturator foramina. The lesser trochanter should also be demonstrated on the AP trauma screening of the abdomen and pelvis.
  • No rotation evidenced by pelvis and lumbar vertebrae being symmetrical. Specifically, the right and left iliac wings equal in size and shape, and spinous processes in center of vertebrae. The sacrum should be centered midline to the symphysis pubis.
  • Radiographic exposure should demonstrate low contrast that visualizes the liver and renal margins, psoas muscle outline, lumbar transverse processes, and lower ribs. The exposure should show good contrast between air, muscle, and fat as these tissues may hold key diagnostic information.

Radiograph #66

image046 This patient presented at a local emergency room with a chief complaint of generalized abdomen pain, nausea, and no bowel movement X 3 days. Does this radiograph meet the diagnostic criteria for the AP supine abdomen radiograph?
Critique of Radiograph #66

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This radiograph does not meet several of the diagnostic criteria for the AP abdomen view. Mainly, the lateral abdominal walls are clipped and distally the ischial tuberosities are not visualized. This radiograph does not display the diaphragm, liver dome, entire spleen, or the lateral tip of the liver is seen. Unfortunately, this radiograph should be repeated using two crosswise placed 14 X 17 cassettes that display the ischial tuberosities and diaphragm. There should be overlap of the two radiographs so that no anatomy is omitted. As for the exposure technique, the lower thoracic vertebrae and ribs are properly exposed. The lumbar vertebrae show good penetration and bony detail. Soft tissues of the abdomen, especially the renal outlines, psoas muscles, and visualized portions of the liver, spleen and urinary bladder are optimal.

Radiograph #67

image047 This patient presented at a local emergency room with complaint of abdomen pain, nausea, and vomiting. The patient also stated he had not eaten in 3 days "because it keeps coming back up." Does upright abdomen radiograph meet its diagnostic criteria?

Critique of Radiograph #67

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Air fluid levels are seen in the abdomen, which may indicate a partial small bowel obstruction. Although fluid levels are seen this does not complete the diagnostic evaluation. It is important that both hemidiphragms are entirely included on the radiograph along with the lateral walls of the abdomen. It is also important that the rectum and sigmoid colon is demonstrated because air and feces can indicate whether or not there is some passage in this segment of the bowel. Clearly, the solution here is to make two upright films on 14 x 17 cassettes turned crosswise. One should demonstrate the upper abdomen to include both diaphragms. The second radiograph should demonstrate the lower abdomen to include the ischial tuberosities. The exposure adequately demonstrates contrast between abdominal structures, air and fecal material within the bowel, and the bony structures such as the ribs and lumbar spine. This radiograph should be repeated to include all required anatomy.

Radiograph #68

image048 These radiographs are examples of two 14 x 17 cassettes turned crosswise to include the upper and lower abdomen. Do these radiographs meet the diagnostic criteria for the AP supine abdomen view?

Critique of Radiograph #68

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Often two films taken crosswise are necessary when imaging hypersthenic type patient with a minimum of 2.5 inches overlap. These two radiographs taken with the cassettes turned crosswise do demonstrate the entire abdomen as required by diagnostic criterion. The ischial tuberosities are included distally and the diaphragm is noted to show the entire liver. The lateral margins of the abdomen are seen as well. There is good overlap of the two radiographs so that none of the abdomen is omitted. As for radiographic exposure there is good contrast in the soft tissue structures and the bowel is well outlined by gas. Bowel gas serves as a natural contrast agent in the bowel that helps outline the mucosa. It is recommended that sufficient exposure (mAs) and low contrast (high kVp) is used to demonstrate the psoas muscle outlines, lumbar transverse processes, and ribs. The ribs and stomach bubble should be clear indicating no motion artifact. Because the psoas muscles are not clearly seen and there is blurring of the ribs this radiograph may need repeating if the upright views do not demonstrate these structures without motion.

Radiograph #69

image049 This series of upright radiographs were taken on a patient with chief complaints of abdomen discomfort and lack of bowel movement x 4 days. After taking laxatives there was no bowel movement and the pain remains. Do these radiographs meet the diagnostic standards for the upright abdomen radiograph?

Critique of Radiograph #69

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This split two view of the abdomen demonstrates how overlapping halves is an effective way to present the abdomen. The question for us is do these two radiographs meet the diagnostic criteria for the AP upright abdomen? Yes they do! There is sufficient overlap to meet this diagnostic criterion. Also, the diaphragm, ischial tuberosities, and lateral body walls are visualized. It can be difficult to determine correct amount of film overlap when crosswise films are taken on tall hyposthenic or asthenic type patients. Therefore, perform two lengthwise exposures so that the iliac crests are demonstrated on both radiographs. Again, a slightly higher kVp should be used to penetrate the spine and ribs. This is a good radiograph that does not need to be repeated and is free of motion artifact. The stomach bubble shows clear outline and the ribs have good detail.

Radiograph #70

image050 This supine radiograph was taken to document the placement of a feeding tube. Note: the feeding tube was placed in the radiology department under fluoroscopy and the radiologist wanted a plain film to document it. Does this radiograph meet the diagnostic criteria for the AP abdomen view?

Critique of Radiograph #70

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This radiograph does not meet the general requirement for the AP abdomen view; however, this is a specific radiograph taken under the order of the radiologist. The diaphragm is clipped as is the right lateral wall of the abdomen. This radiograph does document the placement of the feeding tube as it enters the stomach through the cardiac orifice, descends along the greater curvature of the stomach to end in the distal part of the C-loop of the duodenum. The exposure technique demonstrates the abdomen satisfactorily although there is some degree of motion artifact. This radiograph does not need to be repeated since it demonstrates the specific reason for which it was taken. Also in consultation with the radiologist this radiograph should not be repeated unless directed by the radiologist in keeping with ALARA.

Radiograph #71

image051 Discuss whether or not this radiograph meets the diagnostic standards for the AP abdomen view. Consider this is recent newborn, and tell why the technologist did not use gonadal shielding.

Critique of Radiograph #71

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This radiograph does demonstrate the required anatomy for the AP supine abdomen view. The exposure technique shows good subject contrast although the psoas muscles are not seen when imaging small infants. The main reason this radiograph should be repeated is motion artifact that does not allow for a good interpretation. Abdomen radiographs are taken on expiration. With infants the abdomen rises with inspiration and falls with expiration. Therefore, one must time the expiration carefully since newborns will not hold their breath. Also a short exposure time is necessary to demonstrate structures clearly without motion. When this radiograph is repeated be sure to move the heart monitor leads to the lateral sides so they do not cross the abdomen. Shielding is not used because this is a female and the gonads are within the abdominopelvic cavity. Shielding would obstruct abdominal structures, instead, use good collimation and low mAs exposure in keeping with ALARA.

Radiograph #72

image052 Consider this radiograph taken on a female patient whose complaint was abdomen pain and bloating. Does this radiograph meet the diagnostic criteria for the upright abdomen view, no CXR was taken?

Critique of Radiograph #72

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The diagnostic criteria require that the patient is erect for a minimum of 5 minutes prior to taking the exposure. This will give time for fluid and air to level out. Also the diaphragm must be included on any upright abdomen radiograph unless an erect PA chest projection is also included. Therefore, this radiograph should be repeated to include the diaphragm. Deep inspiration followed by deep expiration will cause the diaphragm to be more elevated. Also hypersthenic type body habitus may require two lengthwise films to include the entire abdomen and diaphragm. All that is needed to complete this study is a coned down view of the upper abdomen that includes the lower 1/5 of the chest. The exposure shows high contrast, which is undesirable for imaging the abdomen. The pelvis is underpenetrated and the abdominal flank is overexposed due to high mAs, low kVp. So, when this radiograph is repeated, increase kVp, decrease mAs, and center the image receptor at least 2 inches above the iliac crest to include the diaphragm.

Radiograph #73

image054 Give your critique of this AP supine abdomen radiograph taken on a patient who presented at a local emergency room with abdominal pain, distention, nausea, and vomiting. Tell what could be done differently to make this a better radiograph.

Critique of Radiograph #73

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This radiograph agrees with the clinical findings of severe abdominal distension. The question becomes, how should the technologist image this patients given the clinical information provided and the patient’s presentation? A suspicion of air in the bowel requires a reduction in the exposure, whereas fluid, such as ascites would require an increase in kVp. It appears the technologist did reduce the exposure, perhaps too much as the spine is very under penetrated. But what makes this radiograph unacceptable is its failure to demonstrate the entire abdomen, especially the lateral walls and the diaphragm. It would be better to initially perform this study with two 14 x 17 cassettes turned crosswise. Nonetheless, this radiograph should be repeated to include the entire abdomen, and although the exposure is satisfactory, reduce the mAs and increase the kVp to soften the contrast and penetrate the lumbar spine.

Radiograph #74

image055 This radiograph obviously does not meet the diagnostic standards for the upright abdomen view. Tell what should have been done to avoid the errors seen on this radiograph.

Critique of Radiograph #74

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It should be noted that the patient suffers ascites and a large amount of air is present in the bowel causing distention. The technologist made two errors, the first is over exposure of the radiograph, and the second is failure to turn the cassette crosswise to include the diaphragm. The exposure error seen here is too much mAs. Notice the obliteration of the femoral condyles, visualized chest, and lateral walls of the abdomen. A distended abdomen is usually caused by fluid, air, or a mass, which may require increasing the kVp or decreasing the mAs. In this case the mAs was increased, which will not penetrate the abdomen, and may cause overexposure where there is a lot of air. Instead, increase the kVp by at least 15% and slightly decrease the mAs, about 30%. This is equivalent to adjusting the phototimer to minus one (-1). A long scale or low contrast is desirable when there is a lot of air or fluid. So repeat this radiograph using two crosswise 14 x 17 cassettes, decrease the mAs, and increase the kVp to penetrate the abdomen without burnout of the chest.

Radiograph #75

image056 Consider this radiograph of the upper abdomen, which is a repeat of the previous radiograph #74. Does this radiograph meet the diagnostic criteria for the upright abdomen view?

Critique of Radiograph #75

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Here we see the exposure is properly adjusted to demonstrate the visualized portion of the lungs and the diaphragm. Notice that with this exposure it is possible to evaluate the bowel pattern and evaluate whether or not there is free abdominal air. Unfortunately the right lateral abdominal wall is clipped; however, both costophrenic angles are seen. This radiograph is sufficient for diagnosis as long as a second radiograph of the lower abdomen is included to complete this view.

Radiograph #76

image057 Consider this portable supine abdomen radiograph taken bedside. Does it meet diagnostic criteria for the AP abdomen view?

Critique of Radiograph #76

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While it may be obvious what is incorrect about this radiograph, the cause may not be so obvious. The lateral walls are clipped, which is caused by collimation. However, the longitudinal axis of the tube is slightly tilted towards the right and caudal to cranial. Notice the angle of collimation on the top left of the radiograph vs. the lower left which is wider. To get the entire abdomen and the lateral margins it is important that there is good tube-part-cassette alignment. It is also important that there is minimal object-film-distance (OID). This person appears to be average size yet the twelfth ribs appear very large and magnified. This is due to a short source-to-image-distance (SID. The exposure is affected by all of these factors including some degree of grid cut-off. Repeat this view using at least 44-inch SID, center the patient to the cassette, and align the tube perpendicular to the image receptor.

Radiograph #77

image058 Does this radiograph meet the diagnostic criteria for the supine AP view of the abdomen; give your reasons for your answer?

Critique of Radiograph #77

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Essentially this is a good radiograph in terms of the exposure. The spine is optimally penetrated while preserving good contrast between soft tissues of the abdomen and air in the bowel. The lateral flanks are not included, which may be due to too much OID or a short SID. Although the pelvis is slightly rotated to the right and the sacrum is not aligned with the symphysis pubis this portion of the lower abdomen and pelvis does not need to be repeated. Instead, include a crosswise film that includes the entire upper abdomen, lateral flanks, and diaphragm to complete this view. Increasing the SID will decrease some of the magnification.

Radiograph #78

image059 Does this single AP abdomen view meet the diagnostic criteria; give reason(s) for you answer?

Critique of Radiograph #78

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This is a supine radiograph of the abdomen that demonstrates good subject contrast. The entire liver, spleen, and renal outlines are well visualized. Bowel gas provides a natural contrast within the abdomen as do the bony structures of the pelvis, spine, and ribs. The supine abdomen view should demonstrate the ischial tuberosities and the tip of the liver rather than the entire liver. The superior limit of the single film AP supine view should be at the level of the eleventh thoracic vertebra. Here we see upwards to the ninth thoracic vertebra. Because this radiograph is taken on deep expiration the diaphragm rises above the eleventh thoracic vertebra. So in keeping with ALARA, omit the upper abdomen as seen here and include the entire urinary bladder and lower portions of the digestive tract. On the upright view include the diaphragm while omitting the lower pelvis if necessary. Therefore, to complete this view one should make a second radiograph of the lower pelvis to include the ischial tuberosities. The exposure factors are adequate for visualization of abdominal structures.

Radiograph #79

image060 Consider this radiograph taken on an elderly gentleman whose chief complaint was abdomen pain, stomach feels full, no bowel movement x 4 days. Discuss why it does not meet the diagnostic criteria for the AP abdomen view.

Critique of Radiograph #79

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The main problem with this radiograph is metal artifacts from the patient’s suspenders obstruct the abdomen. Also the exposure shows high contrast with poor penetration of the lumbar spine. Repeat this radiograph using two crosswise cassettes to include the lateral flanks, increase the kVp by 15% with an appropriate decrease in mAs, and remove obstructive clothing.

Radiograph #80

image061 The clinical history for this radiograph included possible blockage of j-tube and or small bowel. The radiologist gave a protocol for this radiograph to be taken after injection of 75 ml water soluble contrast agent. This is one of a series of 3 radiographs taken over 2 hours. Does it meet the diagnostic criteria for the AP abdomen?

Critique of Radiograph #80

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This radiograph does meet the diagnostic criteria for the AP supine abdomen view. The abdomen and pelvis is rotated due to scoliosis not positioning. Based on the presentation of the patient it would not be possible to achieve a true AP view by rotating the body to the right. The reason for this study was to check the placement of the J-tube. This radiograph meets this criterion. It also shows good exposure technique in differentiating bowel filled with gas from other abdominal structures. The use of proper kVp for low contrast provides penetrated visualized contrast filled areas of the bowel. This radiograph meets diagnostic criteria and subsequent radiographs of this caliber will provide continuous quality for comparison.

Radiograph #81

image062 Do the chest and abdomen portions of this radiograph meet the diagnostic criteria for their individual views? Discuss why or why not in your answer.

Critique of Radiograph #81

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It is common practice to include the chest and abdomen on a single exposure when imaging infants. In this case the abdomen portion of this radiograph does meet diagnostic standards. The bowel pattern is clearly seen. Keep in mind that the renal outline, spleen, and other abdominal structures are difficult to see on the abdomen radiograph of infants. The chest shows poor inspiration and is lordotic in presentation. When performing both the chest and abdomen it is better to make the exposure on good inspiration so that the lung fields are diagnostic. This will reduce the possibility of repeating the chest portion of the radiograph. Patience is needed when imaging infants because respirations cannot be suspended for the exposure. Therefore, pay close attention to excessive motion by the patient, and take the exposure when the abdomen rises. Unfortunately, the chest portion of this radiograph should be repeated with good inspiration and without motion artifact. Also correction for the lordotic position will be possible by angling the tube slightly caudal. The exposure is adequate for both the chest and abdomen.

Radiograph #82

image063 Consider this radiograph of the chest and abdomen taken on a newborn. In particular the physician wanted to evaluate a newly placed umbilical line. Does this radiograph meet the diagnostic criteria for the chest and abdomen, and tell what could be done to make this a better radiograph in keeping with ALARA?

Critique of Radiograph #82

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The main reason for this radiograph is to evaluate the umbilical line which is seen at the level of T8/T9. Motion artifact makes it more difficult to localize the umbilical tube, but it can be seen. This radiograph could have been better if the cardiac lead wires had be moved laterally so not to obstruct the lung and abdominal fields. On initial radiographs it is a good idea to ask the nurse to remove them for the few seconds it takes to make an exposure. Otherwise the lungs show good inspiration with expansion covering 10 anterior ribs. The entire abdomen is seen and there is good contrast between the abdominal structures and bowel gas. In keeping with ALARA a gonadal shield should have been used to protect the male gonads. Otherwise this radiograph does meet the diagnostic criteria for the chest and the abdomen views.

Radiograph #83

image064 This AP supine radiograph of the abdomen was taken to evaluate a distended abdomen and to evaluate the umbilical line on this recently born infant. Does this radiograph meet the diagnostic criteria for the AP abdomen view?

Critique of Radiograph #83

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This radiograph meets the diagnostic criteria for the AP abdomen view. The entire abdomen is included from the diaphragm through the ischial tuberosities. The lateral walls of the abdomen are also entirely included. When a lot of bowel gas is suspected it is appropriate to reduce the mAs to compensate. However, when dealing with small infants, reduction in exposure is not necessary because the exposure is already significantly low. This radiograph shows under penetration of the upper abdomen, but is not significant enough to require repeating the radiograph. The lower thoracic and lumbar vertebrae are under penetrated; however the umbilical line can be seen and its level relative to the lumbar vertebrae can be determined. Overall, this is a good radiograph that does not need repeating and meets the criteria.

Radiograph #84

image066 This patient was born with a condition called gastroschisis. The pediatrician requested abdomen radiograph taken portable supine after being given 25 ml oral water soluble contrast. Does this radiograph meet the diagnostic criteria for the AP supine portable abdomen view? What precautions should be taken when imaging this condition (gastroschisis)?

Critique of Radiograph #84

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Gastroschisis (also called paraomphalocele, laparoschisis, abdominoschisis, or abdominal hernia) is a type of inherited congenital abdominal wall defect in which the intestines and sometimes other organs develop outside the fetal abdomen through an opening in the abdominal wall. The technologist’s role is to maintain a clean sterile environment while imaging as well as produce diagnostic quality radiographs. This is an excellent radiograph that meets diagnostic standards for the AP supine chest and AP supine abdomen radiographs. The lung fields show good inspiration and minimal rotation of the chest sillouhette. The abdomen appears symmetrical and free of motion artifact. The entire abdomen including the lateral boundaries of the bowel is demonstrated. The exposure technique demonstrates good penetration of the chest and abdomen and optimal subject contrast of visualized structures.

Radiograph #85

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Consider this AP supine abdomen radiograph taken to evaluate for RLQ pain in a patient with a history of partial bowel obstruction and scoliosis. Does this radiograph meet the diagnostic criteria for the AP view of the abdomen/pelvis? Consider that this was an acute abdomen series that included an upright abdomen and upright PA chest radiographs.

Critique of Radiograph #85

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It is helpful to know that this was one of three radiographs in the abdomen series. As a stand-alone radiograph it shows good positioning of the patient with minimal rotation of the pelvis. Notice both obturator foramen are open and fairly symmetrical in presentation. Superiorly the eleventh thoracic vertebra is not included as well as portions of the liver and diaphragm. The lateral margins of the abdomen are demonstrated. The radiographic exposure shows good penetration of the lower lumbar vertebra without “burnout” of the visualized bowel gas. It is less important to include the diaphragm and liver dome since these structures will be on the upright chest and abdomen radiographs. This radiograph is considered to meet diagnostic standards for the AP supine view of the abdomen.

Radiograph #86

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The patient history for this exam is to evaluate placement of nasogastric tube since enteric feeding tube is not working. Does this radiograph meet the requirements for the diagnosis?

Critique of Radiograph #86

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The primary concern for this radiograph was to demonstrate the location of the feeding and nasogastric tubes. The technologist did achieve this goal; therefore, the radiograph meets clinical diagnostic criterion. When comparing this radiograph with what is needed for the routine AP supine abdomen radiograph it falls short of what is required for this view. The left lateral abdominal wall is clipped as is the inferior pelvis. Another interesting point is that for feeding tube placement it is sometimes recommend that the cassette is placed in a manner that shows the lower third of the chest and two-thirds of the abdomen. This is especially warranted when the gastric tube cannot be localized within the stomach clinically with a stethoscope. This will demonstrate the location of a gastric tube that is coiled in the esophagus above the lower esophageal sphincter. Overall the exposure technique demonstrates the questioned anatomy. This radiograph does not need to be repeated because it meets standards based on clinical reason for the exam.

Radiograph #87

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This AP supine abdomen radiograph was taken to evaluate this post-surgery abdomen for bowel obstruction. Does it meet the diagnostic criteria for the AP view of the abdomen?

Critique of Radiograph #87

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The superior border of this radiograph demonstrates a portion of the distal lungs, the entire liver and spleen. Distally, the entire pelvic cavity is seen, the lateral abdominal walls are entirely demonstrated. All required anatomy is demonstrated including the diaphragm and lateral margins of the thorax and abdomen. A series of longitudinal closure staples indicate recent surgery. Good contrast is seen between the spine, bowel gas, and intra-abdominal structures. The pelvis and abdomen is highly rotated due to thoracolumbar scoliosis. The cardiac monitor lead wire seen in the field of view does not obstruct a significant amount of anatomy. However, it should be removed or moved to the right lateral margin of the patient to minimize its effect. This radiograph meets diagnostic standards for the AP supine abdomen view.

Radiograph #88

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This radiograph was taken on a patient who is suspected of having a small bowel obstruction. The technologist made two crosswise views to include the entire abdomen. Do these two radiographs meet the diagnostic criteria for the AP supine abdomen view?

Critique of Radiograph #88

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The diagnostic criteria for the AP supine abdomen view include demonstration of the entire abdomen including the lateral flanks, and from the diaphragm through the ischial tuberosities. The exposure technique should demonstrate good subject contrast between abdominal structures like the liver, renal silhouette, psoas muscles, pelvis and spine. These radiographs show an extensive gas filled bowel with the required 2.5 inches of overlap in anatomical structures presented by the two radiographs. This would be an optimal radiographic series except that the left upper lateral flank is clipped. If only the supine view is taken then the upper abdomen should be repeated to include the left flank. However, if the upright view is also taken include both lateral walls on the upright and do not repeat this view in keeping with ALARA.

Radiograph #89

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Consider this radiograph taken on a patient with a medical history of obstipation. What should a primary concern to the technologist as you evaluate this radiograph? What should the technologist do to complete the diagnostic standard for the supine abdomen view?

Critique of Radiograph #89

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This patient has a history of severe constipation that includes obstipation and fecal impaction. Generally two types of constipation are seen medically, obstructed defecation and colonic slow transit (hypomobility). About 50% of constipation cases are obstructed defecation, which has mechanical and functional causes. Slow colonic transit is caused by diet, hormones, medications, heavy metal toxicity, and post- surgical changes. So including the entire abdomen is essential to determining the location of a mechanical obstruction. Therefore the technologist should include a crosswise view of the upper abdomen and lateral wall. The radiograph on the right completes the diagnostic criteria for the supine abdomen view. All required anatomy is seen between the two radiographs. Exposure shows good subject contrast within the abdomen.

Radiograph #90

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This radiograph was returned by the reading radiologist because the diaphragm was not included. What should the technologist do to complete the diagnostic criteria for the upright abdomen view seen here?

Critique of Radiograph #90

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The technologist correctly repeated only the upper abdomen to include the diaphragm. This is a diagnostic criterion that must be met for the upright abdomen view to be acceptable. When evaluating the upright abdomen the radiologist must be able to determine if there is free abdominal air that would indicate a perforation of the bowel, for example, a ruptured diverticulum or ruptured appendix. Clearly there are differential air-fluid levels seen on the initial radiograph. Differential air-fluid levels are two distinct air-fluid interfaces on a horizontal-beam abdominal radiograph at different heights but within the same loop of bowel. Therefore, always include the entire abdomen along with the diaphragm on any upright abdomen view. In keeping with ALARA only the upper abdomen needed repeating. The exposure shows good subject contrast within the abdomen.

Radiograph #91

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This chest abdomen pelvis radiograph taken on a newborn meets diagnostic criteria; however, discuss why it fails for ALARA.

Critique of Radiograph #91

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This radiograph shows good inspiration expansion of the lung fields. The chest shows minimal rotation so that the heart and mediastinum silhouette is easily evaluated. Lung markings are clear and free of obstructing artifacts. The abdomen shows good contrast between structures and visualized catheters show good detail. Bowel gas is seen without motion artifact; the stomach bubble is also clearly seen with sharp edges. However, this radiograph fails on collimation. Both arms and femurs should not appear in the field of exposure. Collimation on all four sides of the film should be seen when imaging infants. The field should be clear of the upper and lower extremities. The technologist did use gonadal shielding in keeping with ALARA. Shielding alone does not compensate for poor collimation as areas that do not have diagnostic value should not be included.

Radiograph #92

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Compare this radiograph to #91 in terms of ALARA and image quality.

Critique of Radiograph #92

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This radiograph shows good collimation along the lateral borders; however, better centering of the patient and collimation on all four borders is recommended. The chest shows no rotation although the clavicles are projected above the apices. Inspiration shows a mere 9 anterior ribs, which is an acceptable compromise for the chest and abdomen combined radiograph. The image quality for the chest and abdomen is good as the thoracolumbar vertebral bodies are well penetrated. Abdominal structures including bowel gas and the umbilical catheter show sharp edge detail. So in comparing the two radiographs is should be clear that patients are different and will have different radiographic presentations. However, the technologist should always make well positioned, well collimated, and properly exposed radiographs that meet diagnostic standards and ALARA. Overall, this is a very good diagnostic radiograph that meets standards for ALARA.






Diagnostic Criteria for the Left Lateral Decubitus Abdomen View

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When the upright abdomen position cannot be performed left lateral decubitus position can be an option. Of course, the upright position is preferred because it routinely offers better information about the abdomen. The left lateral decubitus projection can be made in place of the upright abdomen radiograph when looking for air-fluid levels or free intra-abdominal free air. The left lateral decubitus position places the left side of the patient down and the right side up when lying on their side. The right lateral decubitus position would place the patient on their right side with the left side up. The right lateral decubitus is not used for evaluating free air in the abdomen because when the left side is up an air filled stomach may obstruct viewing free abdominal air under the left hemidiaphragm. In order for the left lateral decubitus view to yield diagnostic information it is important that it is performed properly. This includes proper positioning of the patient, using a horizontal beam, and including all required anatomical structures for this view.

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These side-by-side comparisons of the left lateral decubitus (left) and upright abdomen (right) views show air-fluid levels. While the left lateral decubitus can be used to demonstrate the abdomen the upright abdomen is preferred. The upright allow for visualization of structures better than does the decubitus view, for example, the flanks spine, liver, and other structures are seen in true anatomical positions. The left lateral decubitus view is good for demonstrating free intra-abdominal air.

For the left lateral decubitus projection the patient is placed in the lateral recumbent position on a radiolucent pad to slightly raise the side down sufficiently to be entirely included on the radiograph. A hard surface such as the tabletop or a spine board under the patient will reduce sagging and anatomy cutoff of the side down. Place the back firmly against the vertical upright Bucky aligning the shoulders, posterior ribs, and posterior pelvic wings perpendicular to the tabletop. A sponge or pillow should be placed between the knees to restrict forward rotation of the lower abdomen. The knees can be partially flexed to stabilize the patient as the arms are brought up near the head out of the field of view. The patient must remain in the decubitus position a minimum of 5 minutes to give time for fluid to accumulate and free-air to rise to the high points of the abdomen.

Good centering of the patient to the image receptor is a must in order to achieve an optimal radiograph. The central ray (CR) is directed horizontally to the center of the image receptor. A horizontal beam is used to demonstrate air-fluid levels and free intra-abdominal free air when present. Tube-part-image receptor alignment will have the CR entering the patient approximately 2-inches above the iliac crest. A minimum of 40-inch source-to-image-distance (SID) is required to minimize part magnification. The patient must be placed firmly against the image receptor to minimize object-image-distance, which also causes magnification on the radiograph. The CR should enter slightly higher than the midsagittal plane so to include the entire up side, which is a diagnostic criterion.




Diagnostic Criteria for the Left Lateral Decubitus Abdomen View
  • The left lateral decubitus abdomen radiograph is always performed first in a two or three view abdominal series.
  • Patient should be placed on their left side during transport for a minimum of 5 minutes and ideally 15 minutes prior to imaging.
  • No motion: ribs, diaphragm and gas filled structures should show sharpness; the exposure is made on suspended expiration.
  • The upside (right side) and diaphragm must be entirely included. The right lateral margin of the abdomen must be demonstrated and all lateral soft tissues as well. The entire down side is also of interest and should be included; however, if it cannot, the entire upside is what is required for diagnostic value.
  • No rotation evidenced by pelvis and lumbar vertebrae being symmetrical, specifically, the right and left iliac wings equal in size and shape.
  • Radiographic exposure should demonstrate low contrast that visualizes the liver and renal outline, and lower ribs. Exposure should demonstrate air-fluid levels and free intra-abdominal free air without burnout of visualized bowel gas pattern. The exposure should show good contrast between air, muscle, and fat as these tissues may hold key diagnostic information.

Radiograph #93

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This left lateral decubitus view was taken on a hypersthenic type body habitus using two crosswise views. Do these radiographs meet the diagnostic criteria for the LLD view of the abdomen?

Critique of Radiograph #93

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The hypersthenic type patient requires two crosswise films in order to include the entire abdomen just as with the upright abdomen. Sthenic and asthenic types can be imaged using a single lengthwise cassette. When two cassettes are used a minimum of 2.5 inches of overlap between the two exposures is recommended, which was accomplished by these two radiographs. What is great about this series of radiographs is that the left side (side down) of the abdomen is demonstrated. This is because the technologist raised the down side using radiolucent sponges. What is also good about these radiographs is the exposure and density shows the diaphragm, ribs, and gas shadows are sharp and have great detail. The renal outlines (blue arrows) and spleen (red arrow) are clearly demonstrated. Anatomical components of the lower abdomen and pelvis area are clearly visualized as air may localize above the right iliac wing in some types of body presentations. The one flaw on these radiographs is the position of the anatomical marker (blue circles), which are found in the field of view. Always place the marker in an area where it cannot obstruct visualization of free-air.

Radiograph #94

image067 This left lateral decubitus radiograph was taken on a pediatric patient who was too sick to stand for the upright view. Does this radiograph meet the diagnostic standards for positioning and exposure quality?

Critique of Radiograph #94

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This is another excellent made radiograph in terms of positioning and including all of the required anatomy. Both diaphragms are entirely demonstrated and distally the entire lower abdomen including the rectum is seen. Because this is a sthenic type patient a single lengthwise film was able to capture all of the anatomy. Both the side down and the upside are seen, which allows for evaluating the abdomen for masses, air fluid levels and free abdominal air. The exposure shows good contrast between air and fluid, which is good for identifying free air. However, a slightly lower contrast would be desirable as this will demonstrate the renal outlines, liver and spleen better. Overall, this is a good radiograph that does not need to be repeated.

Radiograph #95

image068 Consider this LLD radiograph taken on a sick intensive care patient. Because the patient was too sick for the upright project the technologist performed this radiograph portably. Does this radiograph meet diagnostic standards for the decubitus view?

Critique of Radiograph #95

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This radiograph shows the entire abdomen including the lateral margins of the abdomen. Particularly, the right diaphragm is demonstrated as well as the region over the right iliac wing where free-air may accumulate. Two points about this radiograph are worth mentioning. First is that the right arm appears in the upper right corner of the radiograph. Soft tissues of the humerus are seen obstructing a portion of the right lateral wall where the radiologist looks for subtle accumulations of free air. The other factor is that the exposure does not show great subject detail. Notice the spine is barely differentiated from the overlying tissues and bowel gas.

Radiograph #96

image065 Does this radiograph meet the diagnostic criteria for the left lateral decubitus view; tell what could be done to make it better?

Critique of Radiograph #96

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This is an acceptable radiograph in that it shows the diaphragm, liver, and entire down side. The exposure does show slightly higher contrast than is desirable, but is within acceptable limits. This could be a better radiograph if the flexed knees were extended so not to obstruct the pelvis. The other point to this radiograph is that there is no collimation distally. The femurs should not be included on a well-collimated radiograph of an infant. This appears to be a male infant making it possible to use gonadal shielding. Overall, this radiograph meets diagnostic standards for the LLD view; however poor collimation and failure to use a gonadal shield is not in keeping with ALARA.

Radiograph #97

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This radiograph was taken on a patient post-surgically as part of a flat and decubitus abdomen series. The AP view included the diaphragm. Does this radiograph meet the diagnostic criteria for the LLD view?

Critique of Radiograph #97

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The radiograph on the left shows good positioning of the patient on a radiolucent sponge to raise the left side. There is slight rotation of the pelvis due to scoliosis, but this does not significantly change the anatomical presentation of abdominal structures. Good contrast and density is seen in the visualized portion of the abdomen and pelvis. If free intra-abdominal air were present it would be seen above the right iliac wing based on this exposure technique. Unfortunately the entire abdomen is not included on this radiograph. The visualized abdomen meets diagnostic criteria; however, a second lengthwise exposure to include the diaphragm is needed (right radiograph). By comparing these two radiographs it is easy to see that the entire abdomen could not be demonstrated on a single film. The diaphragm is seen on the upper abdomen radiograph and the lateral liver edge. It is worth noting that the visualized portion of the chest shows fluid level in the pleural space. Together these two radiographs meet the diagnostic criteria for the left lateral decubitus view. Neither radiograph alone meets the diagnostic criteria. If either the upper or lower abdomen is made first the other must be included to complete the view

Summary: Critique of the Abdomen Views

  • There are basically three AP views of the abdomen that are routinely taken: The AP supine view, the AP upright view, and the decubitus view. The AP abdomen should include from just above the diaphragm down to the ischial tuberosities. For males over the age of 50 be sure to include all of the prostate gland. The lateral body wall should be included on the film using either one or two large cassettes to capture the image (s).
  • Radiographic technique should show good bone, muscle, fat and air densities.
  • The hands and metallic objects should be free of the abdomen. Both hemidiaphragms must be seen on the upright view or the decubitus view (s).
  • Radiographic exposure technique should demonstrate bone and soft tissue adequately.
Always ask, "Did I achieve the diagnostic criteria for this view that I am taking."








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References

Copyright image Copyright 2006-2010 Nicholas Joseph Jr.




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