Online Radiology Continuing Education
for Radiology Professionals

Introduction

Diagnostic Criteria for the AP Pelvis

Diagnostic Criteria for the Pelvic Inlet and Outlet Views.

Diagnostic Criteria for the Judet View

Diagnostic Criteria for the AP and Lateral Views of the Hip

Diagnostic Criteria for the AP and Lateral Views of the Femur

Introduction

Radiologic technologists make and review hundreds of thousands of films daily as part of our routine job performance. Acquiring an acceptable radiograph or digital image requires knowledge of the anatomy, positioning criteria, radiographic exposure, and other skills. In addition the radiographer must know and meet specific diagnostic imaging criteria in order to provide the radiologists images suitable for interpretation. A knowledgeable radiographer assesses acquired images as a point of quality control to make sure it meets the diagnostic criteria. No radiographer wants to pass on poorly made radiographs to the radiologist but when hundreds of images are taken daily it is easy to slack and become complacent. Achieving high quality diagnostic images when hundreds of different images are taken each day requires a conscious effort to maintain quality. Radiographers can at one moment make images of the hand and the next moment called upon to image the foot; the next patient may need abdominal or chest imaging. Not to mention the patient has a role in how images are acquired and their cooperation may vary from extremely cooperative to belligerently uncooperative. Yet the responsibility for achieving a high quality diagnostic image remains with the radiographer. Combining imaging skills with patient skills is truly an artful use of scientific principles and people skills. Occasionally we must be creative in order to present anatomy in a way that meets the diagnostic criteria. For example, a patient may present with extreme pain caused by trauma. The patient may have a deformed limb because of a fracture. Immobility of the affected part may require a creative approach without sacrificing image quality.

Knowing what is to be included in each view and the proper radiographic exposure technique for optimal subject detail is a must for any discussion on image critique. As we view images contained in this module we will also address two important issues: what anatomy should be presented in a specific view, and how should that anatomy be presented. Discussions will also include critique of radiographic exposure technique. For example, a radiograph that is positioned correctly and demonstrates the proper anatomy, must also have optimal exposure technique to yield maximum diagnostic value. The diagnostic criteria for each view in our critique series is given; however, these should already be committed to practice, as this is actually a review of the current standards practiced in radiography. The intent of this learning module is to reaffirm that our universal imaging practices conform to the achievement of specific diagnostic criteria. It is commonly thought by laypersons and some medical workers that radiographers just put the part on a cassette and exposes it, which is far from the truth about how we acquire diagnostic images. Likewise, students are often too busy in school to go beyond what the textbook teaches. For example, the textbook may reference the AP hip projection by discussing the positioning of the part and the point of entrance of the central ray (CR) and degree of tube angle. Time constraints in the classroom may not have permitted your instructor to discuss film critique in sufficient detail, like the anatomical relationships seen on each radiographic projection. Now you can take your time and focus on radiographs we commonly image and review each diagnostic criterion.

You will notice that this critique takes a simple approach to viewing radiographic images. First, the anatomy of each part is reviewed, then the diagnostic criteria for the projection are given, and finally, a discussion is made critiquing the radiograph. This is the template for discussion of each image. By knowing the diagnostic criteria you can compare each radiograph and ask, “Did this radiograph meet the diagnostic criteria?” When a radiograph does not meet the diagnostic criteria then you must decide if it should be repeated or not. Keep in mind that just because a radiograph does not meet all aspects of its diagnostic criteria does not mean it is without diagnostic value. Sometimes diagnostic criteria are met using a series of images for a particular view. So consider this film critique relative to patient presentation and how we perform clinically. At times, additional views may be necessary to complete a diagnostic criterion such as the proximal femur is adequately display, but the acetabulum is underpenetrated needing an additional image. The pattern of this critique is that first a radiograph is presented for you to observe. You should jot down your own critique of the radiograph using the diagnostic criteria as a guide. You should do this before you read the author’s review of the radiograph as this will help you improve your critique and imaging skills. Then the author using the stated diagnostic criteria as a reference presents a discussion. Your notes should discuss what should be done to correct an unsatisfactory radiograph including positioning, anatomy demonstrated, and radiographic exposure technique. Hopefully this process will become a permanent pattern for you as you review your images before presenting them to the radiologist who gives a diagnostic reading. Share your image critique with your colleagues to get their opinion and to stimulate professional discussions.

Final radiographs are affected immensely by exposure technique selected and whether or not the patient is cooperative. Not all images that are eye pleasing when casually viewed are diagnostic to the keen eye of a radiologist. Radiographers must combine their knowledge of diagnostic criteria and image quality to assure quality diagnostic radiographs are made during a diagnostic study. Film critique greatly reduces repeat imaging and patient call-backs because of nondiagnostic radiographs. Paramount to diagnostic viewing is the ability of radiographers to present high quality diagnostic medical images time after time no matter how the patient presents. The hallmark of a good radiographer and the most important point of film critique is to acquire quality radiographs even in the most difficult circumstances. While most patients cooperate for imaging procedures there are times when a patient is too young to understand the need for them to cooperate, or the manifestation of alcohol use is a factor, or even a language barrier that can hinder instructions to the patient and may diminish cooperativeness. Yet no specific circumstance inherently lowers or raises the bar for malfeasance or nonfeasance that haunts poor imaging. Often with today's shortages of radiologic technologists inexperienced radiographers are set on their own to clear images for interpretation without the precious benefit of critique by a seasoned professional technologist.

Experienced radiographers know that in order to evaluate any radiograph for technical excellence a solid foundation in how the four radiographic densities (muscle, fat, bone, air) are balanced when a chosen set of exposure factors are selected. A good exposure technique must provide adequate density and good subject contrast that maximizes the visualization of bone, muscle, fat and air. Balancing these densities require a good understanding of how exposure factors like milliamperage (mA), kilovoltage (kVp), source-to-image distance (SID), object-to-image distance (OID), use of grids, and patient body habitus and tissue make-up interplay. Bone is the most radiopaque of the four radiographic densities. Air is the most radiolucent density, which is dark on a radiograph. Between the light density of bone and the dark radiographic density of air are intermediate densities caused by muscle and fat. Together these four radiographic densities create a mosaic of gray tones that detail subject contrast and background density. A fifth density, metal, may be a part of the radiograph in the form of a prosthetic implant, or radiopaque iodinated contrast agent.

When present, metal also contributes to subject contrast. Metal is more radiopaque than bone and is the main component of implanted prosthetic devices. Metal is used extensively in radiology to enhance subject detail. Special formulations of iodine and barium are used in radiographic contrast agents and are the opacifying moiety in these materials. Using a contrast agent such as barium sulfate or iodine solutions allow us to demonstrate information about some structures better than if without it. For example, diagnostic detail of the alimentary tract not seen on routine radiographs, but can be seen when a oral contrast agent is used. Distinction of pathology in the esophagus, stomach and colon are best seen using barium sulfate or oral iodinated media. Likewise, blood vessels, lymph nodes, and solid organs such as the liver, kidneys, spleen, pancreas, and such are best demonstrated using intravenous iodine radiopaque contrast agents for some radiological studies. Intrathecal administration of a sterile water-soluble contrast agent can demonstrate the subarachnoid space and menenges in the spine. Altering subject contrast is necessary to enhance diagnostic value for many radiological studies. As technologists, we are able to use radiographic technique selection to enhance the display of many structures with and without using contrast agents. Technique selection is especially important when imaging bone for fine detail and to demonstrate sharp contrast of cortical bone margins.

Evaluating radiographic density, subject contrast, image detail, and anatomical presentation of each radiographic projection is part of film critique. Prior to submitting a radiograph for interpretation the technologist should evaluate subject contrast. Bone, muscle, fat, and air should be well balanced throughout the radiograph along with displaying good background density. As we present many radiographs in this module it is our goal to improve your ability to evaluate radiographs prior to submitting them for interpretation. It is our hope that you critique each radiograph in a way that encourages perfection at using diagnostic criteria, which are the standards by which we image. We also image using the standard of practicing ALARA (as low as reasonably achievable) in administering radiation for diagnostic purposes. Therefore, it is the purpose of this critique to instill the principles of diagnostic criteria and getting it right nwith the first radiographic exposure. Reducing radiation dose without compromising diagnostic quality is also a primary goal.

Radiographs of the lower extremity are commonly taken, so the radiographer should be very familiar with the anatomy, positioning, and proper exposure techniques required to image it. The main imaging parts of the llower extremity can be thought of in terms of the pelvic girdle, proximal femur, distal femur and proximal tibia (knee), leg, ankle, and foot. We will begin our critique with the pelvis, hip and proximal femur. Imaging of the hip and pelvis often becomes routine so some radiographers regard the hip as an uncomplicated structure anatomically. The result is that it may not get the attention to diagnostic criteria it deserves. Hopefully we will change this point of view (if you have it) by the time you have completed this module. The hip joint is not a simple joint; in fact it has the most extensive motions of all joints of the lower extremity. So let’s start our critique by reviewing the anatomy of the pelvis, hip and proximal femur. The knee, tibia, and fibula will be covered in part II, and the ankle and foot in part III.

Anatomy of the Pelvis, Hip, and Proximal Femur

Pelvis and hip injuries occur frequently from falls, automobile accidents, sports activities, work related injuries and so forth. Chronic pain is also an indicator that frequently requires radiographic imaging. In order to properly image the hip the radiographer must be familiar with its anatomy and how to properly position it for correct diagnostic referencing. Good radiographic imaging should always begin with a solid understanding of the anatomy of the part to be demonstrated. Radiography involves projecting each individual patient’s anatomy in the proper anatomical reference using standard criteria acceptable for diagnosis. Anatomy is often a first course in any radiology educational program because it is basic to all imaging studies and radiological procedures. In this section we will discuss the basic anatomy of the hip relative to plain film imaging. Even if you are a computed tomography (CT) technologist or a magnetic resonance imaging technologist you too can benefit from the anatomy portion of this module. Our purpose is to understand how we should present hip anatomy and soft tissue structures for diagnostic interpretation. Knowledge of radiographic anatomy is the basis for accurate diagnostic positioning. Finally, as radiographer’s we must understand the importance of characterizing bone pathology, especially fractures. For example, a pelvic ring fracture must be characterized as stable or unstable. It is our responsibility to provide radiographs that allow the radiologist to determine injury and fully characterize it in a diagnostic manner that leads to treatment.

The astute student of radiography will ultimately gain knowledge of some of the many normal anatomical variations that can even confound physicians. Sometimes the unwary technologist may be fooled by ossification centers that mimic fractures. Traumatic or chronic pain may cause the technologist to not position the part properly. As a result the radiograph may fail to meet diagnostic imaging standards. Improper positioning can cause overlapping of normal structures or simulate an abnormality. The point here is poor positioning can simulate pathological findings. Radiologists are aware of positioning gamut’s and anatomical variants when interpreting radiographs. However, the role of the technologist is to present radiographs that meet known diagnostic criteria void of ambiguity. One of the primary purposes of this film critique is to review the diagnostic criteria and provide you the tools needed to determine when they have been met for any particular projection. The diagnostic criteria references positioning, anatomy demonstrated, and optimal radiographic exposure and subject contrast.

Let’s begin our discussion with the pelvic girdle, a term referring specifically to the two hip or innominate bones. Each hip bone is a composite of the ilium, ishium, and pubis that fuse at the acetabulum that receives the head of the femur. The ilium is the largest part and forms the superior portion of the hip bone and acetabulum. The ischium forms part of the inferior and posterior portions of the acetabulum and hip bone. The pubis forms the anterior and inferior parts of the hip bone and acetabulum. The fusion of these bones is completed in the mid teens. The term pelvis includes the sacrum, coccyx, and two hip bones.

This radiograph of a pediatric pelvis demonstrates the development of the three bones of the hip (Ilium-A, Pubis-B, Ischium-C) that will later fuse at the acetabulum. Notice that the acetabulum is not completely formed in this child, neither is the femoral head (D).

This 3-D computed tomography image shows a lateral view of the pelvis with the femur removed to demonstrate the acetabulum (D). The acetabulum is formed by the fusion of the ilium, ischium (H), and pubis (E). Some parts of the ilium that are demonstrated are: iliac crest (A), anterior superior iliac spine (B), anterior inferior iliac spine (C), ala or wing (F), and posterior superior iliac spine (G).

Radiographers should be familiar with the following labeled parts of the pelvis seen in the radiograph above: Iliac crest (A), Iliac wing (B), Sacroiliac joint (C), ASIS (D), Acetabulum (E), Femoral head (F), Femoral neck (G), Greater trochanter (H), Lesser trochanter (I), Ischium (J), Superior pubic ramus (K), Inferior pubic ramus (L), Obturator foramen (M), Symphysis pubis (N), Sacrum (O).

The pelvis is imaged for many reasons some of which are: trauma evaluation, chronic pain, and developmental abnormalities. Imaging the pelvic ring is particularly important as part of the trauma survey. When we speak of the pelvic ring we are referring to the ring of bone forming the upper limit of the true pelvis. The ring is formed by the sacrum and two innominate bones. Strong articulations join the hip bones to the sacrum at the sacroiliac joints, and between the pubic bones at the symphysis pubis. The reason it is important for technologists to understand the dynamics of the pelvis and pelvic ring is that there are several pelvic articulations that can become unstable due to trauma. When we talk about critique of the pelvis and hip it is important to understand that the sacrum is one of the keystone functional parts of the pelvis and lower extremity. It distributes weight vectors through the femorosacral sacral plane (a.k.a. femorosacral arch) that supports the spine over the legs. Anteriorly the pubic rami perform stabilization functions; however, this function is less important than that of the posterior ring functions. When imaging the pelvis for trauma the radiographer must provide images that allow the radiologist and orthopedic surgeon to distinguish stable fractures from unstable fractures. Acetabular and hip fractures must also be demonstrated in a way that allows them to be characterized as part of the diagnostic criteria.

The anterior pelvis presents the pelvic ring (blue dotted circle) is formed by the sacral promontory posteriorly, the arcuate ridge of the ilium and superior pubic ramus of each innominate bone. The posterior pelvis (Post) shows the articulation of the innominate bones with the sacrum. The upper portion of the sacroiliac joint (white arrow) is a strong fibrous articulation that gives great ligamentous stability to the joint. The lower portion of the S.I. joint (yellow arrow) is a synovial joint that gives some mobility to the joint, but contributes little to the stability of the pelvic ring.

Because there is no separation between the abdominal and pelvic cavities some anatomists emphasize the arbitrary division of the true and false pelvis. The false pelvis is that portion of the pelvis above the pelvic brim; the true pelvis is that portion of the pelvis below the pelvic brim. The importance of the true pelvis is that it contains the urinary bladder, female reproductive organs, and the rectum. Not only does it form a bony frame around these structures, but also it limits the space available for birthing. One can see distinct differences in the pelvis of the male vs. the female pelvis related to the child carrying function of the female pelvis. Differences between the male and female pelvis is the most important way to differentiate gender based on anatomy.

Pelvic Stability

The bony pelvis lacks inherent structural stability, and so is stabilized by a system of tightly woven ligaments and muscle that provide its support. Strong ligaments arranged transversely resist forces that can externally rotate the pelvis, thereby opening it. Among these are the short posterior SI ligament, the anterior SI ligament, the iliolumbar ligament, and sacrospinous ligaments. Their function is to counter apposing forces such as AP compression. These ligaments fail when force exceeds their ability causing compression injury. Vertical stability of the pelvis is primarily due to the short and long posterior SI ligaments. Interosseous ligaments within the sacroiliac joints also provide some additional vertical stability.

Dense ligament arrays hold the bony pelvis together. Some of these ligament insertions are shown on the schematic images (blue lines). While it is not our purpose to name all of these ligaments it is important to understand the general distribution of ligaments and their role in stabilizing the pelvis. For example, the sacrotuberous ligament is a long band of fibrous tissue that extends from the posterior superior and posterior inferior iliac spines and from the back and sides of the sacrum/coccyx to the ischial tuberosities. Their role is to resist posterior rotation of the lower sacrum.

The take home point is that with pelvic fractures these ligaments can be disrupted and cause instability of the pelvis. Notice the iliospinous ligaments that attach the fifth lumbar transverse processes to the ilium (posterior pelvis image above). Avulsion type fractures of the fifth lumbar transverse process may be the single indicator of pelvic instability when seen on plain film x-ray.

These three coronal MR images show the tremendous networks of ligaments and muscles that stabilize the bony pelvis. They also can cause the pelvis to shift due to their pull when high impact forces separate bone or joints causing pelvic opening or pelvic compression injuries.

Again these ligaments can be partially viewed from the side. These ligaments are named according to their origins and insertions. Some of the more important ligaments that stabilize the pelvis are shown by blue lines on the pelvis image above. From superior to inferior are: posterior SI ligaments, sacrospinous ligaments, sacrotuberous ligaments, and sacrococcygeal ligaments. Though many ligaments support the pelvis some provide passageways into and from the true pelvis pelvis and perineum. The greater sciatic notch (A) guards the entrance into and out of the true pelvis. The lesser sciatic notch (B) provides an opening into the perineum. The coronal MR image on the right shows muscle and ligaments supporting the pelvis.

• Type A, posterior arch is intact; however, stable fractures may be present that includes avulsions of the iliac spine, iliac crest, ischial tuberosity, wing fracture, unilateral and bilateral pubic rami fracture, sacral fracture, or sacrococcygeal fracture. The pelvic brim is also spared, and these fractures do not involve the SI joints.
• Type B, incomplete posterior arch disruption occurring with pubic diastasis, anterior SI joint disruption, anterior sacral buckle fracture, AP and lateral compression injuries, internal and external rotational injuries, and accountability for stability of rotational and vertical injuries
• Type C, complete posterior arch disruption. These are the most severe types of pelvic ring fractures caused by vertical shear, shear, AP/PA, and lateral compression. These occur with ipsilateral and contralateral internal or external rotation of the pelvis due to SI joint fracture/dislocation. These types are rotationally and vertically unstable.

A rotational injury of the hemipelvis causes serious anatomical disruptions in the pelvic cavity. An external rotation of the hemipelvis increases the volume (pelvic opening) of the pelvic cavity causing life threatening hemorrhage. This type of injury must be reduced as soon as possible to control bleeding. Often these patients are immediately wrapped in a pneumatic antishock suit until permanent fixation reduction can be achieved. If bleeding is not stopped, vascular embolization by interventional radiology may be called upon to attempt control of bleeding. It is important that when imaging the pelvis the radiographer is aware that they are demonstrating the pelvic components in a way that helps determine pelvic stability.

The female pelvis (left) has a greater pubic angle than the male pelvis (right). The wings of the ilium are more flared in females than males, and the true pelvis is broader in females to accommodate passage of the fetus during childbirthing. Pelvic features can be appreciated for their obstetric, forensic, anthropological, and paleontological concerns.

These two 3-D images made from axial CT data show the pelvis of a pregnant woman. The fetus (white arrow) has not entered the birth canal of the true pelvis. Notice the fracture of the left pelvic ring and left acetabulum demonstrated by the yellow arrow. These features can also be seen on the 3-D surface rendered image on the right. It is important to properly image the pelvis in both males and females, especially in context of implications to child bearing following injury to a female. Alignment of the pelvis following injury is of great concern to orthopedists. It is important to demonstrate the pelvis in its correct anatomical orientation for trauma imaging.

Anatomy of the Femur

The femur is the longest and strongest bone in the body. It functions to transfer the weight of the body through the lower extremity to the foot to facilitate locomotion. Because of the function of weight transference the hip joint and knee joint often is the source of chronic pain and injury from trauma like a fall. The proximal femur has distinct features that allow it to articulate with the hip bone.

The proximal femur and hip is seen from the anterior view on the 3-D volume rendered CT image on the left. The right CT image shows the posterior aspects of the proximal femur and hip joint. Structures that should be reviewed are: superior pubic ramus (A), inferior pubic ramus (D), ilium (B), head of femur and hip joint (C), and ischium (E). From the posterior view structures demonstrated are: the neck of the femur (F), greater trochanter (G), and lesser trochanter (H). The intertrochanteric crest is seen as a sharp ridge of bone on the posterior side of the proximal femur between the lesser and greater trochanters.

This AP hip radiograph demonstrates some of the important parts of the hip and proximal femur that should be identified. Structures demonstrated are: acetabulum (A) with the femoral head articulation, greater trochanter (B), lesser trochanter (C), and the femoral neck (C). Notice that the femoral neck is not foreshortened and the entire proximal femur and hip bone is well penetrated. Reviewing radiographic anatomy with each projection taken daily is a good way to keep it fresh in one’s mind and it leads to critiquing each radiograph before sending it for interpretation.

The hip is sometimes imaged in the horizontal beam lateral and frog-leg lateral projections, therefore the radiographic anatomy of these positions should also be reviewed at this time. Consider the two radiographs below that demonstrate the anatomy of these projections.

The identified parts of this AP axial frogleg position radiograph are: wing of ilium (A), acetabulum and hip joint (B), greater trochanter (C), femur (D), neck of femur (E), lesser trochanter (F), ischium (G), superior ramus-pubis bone (H), and inferior ramus-pubis bone (I).

This radiograph demonstrates the axiolateral projection (a.k.a. Inferosuperior projection). The labeled parts of the hip and hip joint are the femoral head (A), neck of femur (B), greater trochanter (C), Shaft of the femur (D), ischial tuberosity (F), lesser trochanter (E), and the acetabulum (arrowheads).

Diagnostic Criteria for the AP Pelvis and Hip

Throughout this module we will use standard radiology terminology to describe exposure technique, positioning, and tube angle descriptions. The term overexposure is used to describe a dark radiograph owing to too many photons producing the, or excessive milliamperage/time (mAs). Underexposed is a descriptive term for insufficient photons to expose the radiograph and the mAs should be increased. The term underpenetrated is a term meaning there is not enough energy in the x-ray beam to penetrate the part. Beam quality or penetrability is directly controlled by the kilovoltage selected (kVp). An underpenetrated radiograph can be corrected by increasing the kVp, likewise, decreasing the kVp can compensate for an overpenetrated image.

When improper positioning of the patient is the cause of an unacceptable radiograph we call this a positioning error. Medical radiographs must meet specific diagnostic standards, although there is great variation in acceptable images. When a radiographic image is below the acceptable because of improper positioning is should be repeated. We discuss this type of error in the context of a positioning error. Tube error is a term that can mean improper point of entry of the radiation beam, specifically, the central ray (CR). It can also be due to improper degree of tube angle, or improper direction of the tube, e.g. a vertical beam that should be horizontal. These terms should not be confusing since they are commonly used in radiology and are standard descriptions among radiographers.

Any object that obstructs the anatomy under investigation and can be removed should be removed because it will cause an image artifact. Sometimes with trauma imaging artifacts like ECG monitor leads, oxygen saturation monitor lead or cord, or even a necklace hidden under a cervical collar should be removed or repositioned out of the critical field of view. Artifacts superimposed on pathology must be removed and the image repeated for obvious medical and legal reasons. Anatomic artifact caused by superimposed structures like the hand over the pelvis or hip must also be repeated. Equipment artifacts like processor streaks, improper grid alignment causing grid lines on the radiograph, quantum mottling, or digital noise must all be repeated and cannot be considered acceptable radiographs.

• These lessons are organized so that you can review anatomy and positioning of the most common views of the lower extremity. Radiographs are presented for you to critique using established diagnostic criteria which are presented for each view. The author's critique of each image is presented for you to compare with your notes. The goal is to promote effective learning. So use a pencil and a writing pad to jot down your critique of each image prior to reading the authors critique. Compare your notes and see how accurately you are critiquing each radiograph. Obviously only the main points of critique are presented as you may have other observations worth mentioning above the author’s notes. Upon completion you may take brief generalized examination, which presents questions from samples of the topics and images in this module. Remember, this is a three part module and you must complete all three sections to get credit for this article.
• Upon completion, you may take brief exam which presents questions on a sampling of images.

• Overexposure (too much mAs)
• Underexposure (too little mAs)
• Overpenetrated (too much kVp)
• Underpenetrated (too little kVp)
• Positioning error (patient position)
• Tube error (improper tube angle)

AP Pelvis Critique

For the AP pelvis view the lower extremity and feet are internally rotated 15-20 degrees from vertical. Internally rotating the lower extremity places the femoral necks parallel to the image receptor and maximally demonstrates the femoral neck angle. Placing the anterior superior iliac spines (ASIS) of each hip bone equal distance to the tabletop assures the pelvis is not rotated. Palpating the iliac crest will allow you to adjust its position 1 to 1 ½ inch below the upper margin of the cassette. The entire pelvis and proximal femora should be seen on the radiograph. The greater trochanters should be seen in profile laterally and the lesser trochanters seen on the medial border of the femora. The ischial spines should be equally demonstrated and symmetry of the iliac wings. The sacrum and coccyx should be aligned with the pubic symphysis.

This AP Pelvis radiograph was taken on a patient with a history of chronic right hip pain. Does this radiograph meet the diagnostic criteria for a non-traumatic pelvis x-ray?

This radiograph is good in that it includes all of the anatomy required for diagnosis. The entire ilium and iliac crest is demonstrated superiorly, inferiorly the proximal femora are seen including the lesser trochanter. The pelvis is not rotated and the sacrum/coccyx is midline to the pubic symphysis. The only positioning error seen is that the right hip is not internally rotated, which causes foreshortening of the neck of the femur. Compare the positioning of the neck and greater trochanter of the right femur to the left femur which is correctly positioned. A second coned AP of the right hip joint with internal rotation should be added to this AP pelvis view to complete the requirements for image quality. The acetabulum is well penetrated as are the sacroiliac joints (SI joints). Soft tissue detail is sufficient to show blood or sinus tracts that indicate an open fracture. This is overall a good radiograph in terms of the anatomy included and radiographic technique.

This AP Pelvis radiograph was taken for history of trauma (motor vehicle accident). Does it meet the diagnostic criteria; give reasons for your answer?

This radiograph is not acceptable because the part is underpenetrated. Notice that the right sacroiliac joint and acetabulum are not well penetrated. The basic problem is that this is a high contrast image with few radiographic density differences in the bony pelvis. The overall quality could be improved by increasing the kVp and lowering mAs. The 50/15 rule should be used to adjust the contrast scale. Because this is a trauma image the lateral margins of both greater trochanters should be seen. Magnification of the pelvis has resulted in the lateral femora and anterior pelvis to be partially omitted. To correct magnification use at least a 40-44 source-to-image-distance (SID), and in some cases more distance may be required to get both hips on the radiograph. This radiograph must be repeated to meet the diagnostic criteria for the AP pelvis view.

This AP Pelvis radiograph was taken for chronic left hip pain. Does it meet the diagnostic criteria; give reasons for your answer?

At first glance it may look like the left hip is not properly rotated; however, closer inspection reveals a congenital abnormality of the femoral head and neck. So the pelvis is properly positioned and all required anatomy demonstrated. Yet, this is not an acceptable radiograph because comparing the right and left hip joint and sacroiliac joint there is distinct underpenetration of the right pelvis. The radiograph exposure technique shows high contrast evidenced by the under penetration of the right acetabulum and the entire sacrum. Strive to achieve a balance in contrast to demonstrate good penetration of the femora heads and sacroiliac joints. Unfortunately, this radiograph must be repeated because there are two nonadjacent areas of underpenetration.

This AP Pelvis radiograph was taken to evaluate the pelvis and left hip s/p ORIF left hip. A lateral left hip was also taken. Does this AP view of the pelvis meet diagnostic standards for the pelvis?

This radiograph is taken to evaluate the surgical fixation of the left hip. With this in mind it we should evaluate this image based on the radiographic quality around the hip. Keep in mind that the sacral relationships should be demonstrated as well. The positioning provides a good look at the pelvis and bilateral hips without rotation. The radiographic exposure shows under penetration of the pelvis. This is evidenced by the under penetration of the lower lumbar spine (arrow). High contrast pelvis x-rays should not be taken because the sacrum and acetabula may not be well demonstrated. There is a lot of bowel gas and fecal material that makes this radiograph particularly difficult to image.

This radiograph was taken for blunt trauma involving the abdomen and pelvis. This radiograph was taken during a trauma team alert in which the patient was receiving continuous medical care. Based on your experience with trauma team imaging does this radiograph meet the diagnostic criteria for a portable AP pelvis; give reasons for your answer?

It is often difficult to obtain optimal positioning for portable imaging during a team trauma approach. Radiographs are often taken in the “as is” position and the main concern is to include as much anatomy as possible quickly. But what is in the radiographer’s control is the removal of the metal from the transport safety belts like what is seen on this radiograph. Obstructing the view of a single injury could have important medical and legal consequences. Artifacts from the spine board are acceptable since this is just a general survey. This radiograph should be repeated when the patient is stable. Notice the left obturator foramen is narrowed and the sacrum/coccyx is rotated towards the right hip. This is caused by rotation of the pelvis towards the left (LPO). It is important to distinguish radiographically a rotated positioning error from a rotated pelvis due to trauma that could indicate an unstable pelvic fracture. The left femoral neck is foreshortened and the lesser trochanter is seen in profile. This is caused by external rotation of the left leg. The follow-up radiograph will need to correct these positioning errors if a fracture is not suspected based on this initial portable radiograph. This radiograph should be repeated when the patient is stable, or if brought to the radiology department for other radiographic studies. Include both iliac crests with the patient flattened, femurs can be internally rotated.

This radiograph was taken for blunt trauma involving the abdomen and pelvis. This radiograph was taken during a trauma team alert in which the patient was receiving continuous medical care. Based on your experience with trauma team imaging does this radiograph meet the diagnostic criteria for a portable AP pelvis; give reasons for your answer?

This radiograph of the pelvis to r/o fracture or dislocation of the hip joint is adequate to diagnose pelvis injury. But when an obvious dislocation of the hip joint as seen here is present, the radiographer should include all of the prosthetic hip replacement. It must be determined that no fracture occurred at the distal end of the prosthesis prior to reduction of the hip. A coned AP hip projection should be made to include the entire prosthesis. Radiographic exposure technique is adequate for the pelvis, but overexposure of the femurs and soft tissues of the proximal thigh is seen. Again, adjusting the kVp and mAs to give lower contrast with good penetration of the proximal femurs is recommended.

This radiograph was taken to check alignment of the pelvis postoperatively for pelvic ring and left hip fractures. The patient’s sacrum was unstable and was also stabilized with internal fixation. Is this a good radiograph that meets the diagnostic criteria?

This is a very good pelvis radiograph taken for post-surgical internal and external fixations of the pelvis and femur. Both femurs are accurately positioned and there is minimal rotation of the pelvis due to positioning. It is important for the technologist to be familiar with the different surgical procedures when we talk about film critique. For example, you cannot include the entire left hip’s internal fixation on the film because it is a femoral rod that extends to the knee, which would not be true of some types of fixation devices. Radiographic technique is adequate for all bony structures of the pelvis. Note the fractures and unstable pelvis is supported by external fixation.

Patient history is acute trauma to the left pelvis due to a fall. This radiograph was not made with a mobile x-ray machine. Does this radiograph meet the diagnostic criteria, what should be done to make this a diagnostic study?

Here we see the iliac wings are clipped as well as the left hip. These finding along justify repeating this trauma radiograph. The other positioning concern is the obvious fracture of the left proximal femur which is not fully demonstrated (arrow). There is significant magnification of the pelvis that may have contributed to omission of the anatomy. This radiograph should be repeated correcting SID and positioning errors seen. Radiographic exposure technique is adequate. There is good bone trabecular detail seen and the acetabula and sacrum are both well penetrated.

This patient presented to the emergency room of a trauma hospital as a transfer with known pelvic ring fracture. Upon arrival a pelvis x-ray was ordered to look at the pelvis. Does this radiograph meet the diagnostic criteria for the AP pelvis projection?

This is a very good radiograph of the pelvis and bilateral hips. This image is not too dark as you may have suspected. The over penetration seen here is needed to penetrate the contrast filled bladder. The purpose is to evaluate potential injury that may have damaged structures within the true pelvis (bladder, uterus, rectum) resulting from the left innominate bone fracture. Notice that the left arcuate line of pelvic brim is fractured and displaced through the acetabulum (arrows). The technologist answered two important concerns: displacement of the left pelvic ring fracture and whether or not there is rupture of the urinary bladder. The radiographic technique is excellent for demonstrating a well penetrated bladder, hip bones and acetabula, and the femora.

This patient presented to the emergency room of a trauma hospital as a transfer with known pelvic ring fracture. Upon arrival a pelvis x-ray was ordered to look at the pelvis. Does this radiograph meet the diagnostic criteria for the AP pelvis projection?

This is a very good radiograph of the pelvis. The required anatomy is entirely included from the iliac crest through the lesser trochanters of the femurs. The pelvis is mildly rotated as the right and left obturator foramen are not symmetrical. Both femurs are internally rotated displaying the trochanters in their proper anatomical positions. Overall, positioning of the patient for this projection is good. The radiographic exposure technique is slightly towards high contrast; however, the bowel, urinary bladder, and soft tissues are adequately displayed. Mild burn-out of the greater trochanters and laterally displayed parts of the ilium, but not significantly. Overall, this is a good radiograph that meets the diagnostic criteria.

The ordering orthopedic surgeon requested an x-ray of both hips by specifying an x-ray of the pelvis. The request said, “Pelvis x-ray to include both hip prostheses.” Did the technologist produce this radiograph in keeping with the diagnostic criteria?

Radiograph exposure technique is adequate for the anatomy being demonstrated. Paying close attention to the patient history that goes with each study will eliminate unnecessary exposure in keeping with ALARA. In this case the physician specified post-operative imaging of both hips prosthesis on the pelvis order. For this radiograph the technologist is required to entirely include both hips and the entire prosthesis of both proximal femurs. To do this the upper part of the pelvis (above the yellow line) could have been omitted and more of each femur included. Based on the history for this exam the radiograph must be repeated. Again, patient history and rationale for each image can result in modification of the diagnostic criteria. When in doubt of what the ordering physician wants you should clarify orders before performing any x-ray imaging. When repeating this radiograph be sure to put the patient identification marker in an area that does not obstruct the hip or femur.

What is your critique of this AP pelvis radiograph taken upright to evaluate both hip joints?

This radiograph shows an upright AP pelvis view to evaluate the hips. Notice that the entire pelvis is included. The femurs are internally rotated only slightly and both femoral necks are properly demonstrated without foreshortening. Distally both lesser trochanters are demonstrated on the radiograph and the entire ilium and iliac crests are seen superiorly. Radiographic technique is adequate for this film. The acetabula are well penetrated with good bone detail and contrast.

This AP pelvis radiograph was taken for chronic bilateral hip pain. Does it meet the diagnostic criteria for the AP pelvis view?

This is simply not a good radiograph because the right ilium and right proximal femur is partially clipped. True, the femur is not part of the pelvis, but it is part of the diagnostic criteria for the AP pelvis view. Including the appropriate anatomy under study is required for all radiographic projections. Also, the femurs are not internally rotated which would reduce foreshortening of the femoral necks and profile the greater trochanters laterally. Radiographic exposure technique shows adequate penetration of the acetabulum and good contrast densities across the iliac wings. Soft tissue detail is displayed, so no change in exposure technique is needed.

Given a history of acute trauma from a fall, does this AP pelvis radiograph meet the diagnostic criteria?

The most obvious observation is that the subject contrast is too high. This is evidenced by the underpenetration of the sacrum and “burn out” of the femurs. High contrast caused by low kVp is always unacceptable for imaging the pelvis. A good measure of proper contrast is to look at the upper sacrum and lower lumbar spine. This area should be well penetrated. The acetabula and femurs should be well penetrated but not overexposed. The other issue is that the patient’s left hand overlies the left hip. Guarding is a typical response to acute pain so be sure the subject is clear before exposing the part. Based on these observations the radiograph must be repeated.

This patient was brought to a local emergency room on a spine board with suspected multiple traumatic injuries. Does this radiograph meet the diagnostic criteria for a portable AP projection of the pelvis?

Imaging for trauma in the emergency room as part of the trauma team requires experience and skill to get the best radiograph the first attempt. This portable AP pelvis radiograph demonstrates enough of the anatomy to give the trauma physicians a general diagnosis of injury. It is not uncommon to clip a minimal amount of anatomy when the patient is on a spine board and the image taken on a Stryker bed. This is because this presentation of the patient will have a lot of object-to-image distance (OID) associated with part magnification. Using maximum source-to-image distance (SID) can only partially compensate for excessive OID. Keep in mind that additional imaging of the pelvis will be made when the patient is stable and brought to the radiology suite for other plain films, CT, or other studies. There is adequate radiographic contrast and detail seen on this film. The fracture of the left acetabulum and pelvic ring is easily observed. The technique is inadequate for complete diagnosis because the posterior pelvic elements, mainly the sacrum is underexposed. Stability of the pelvis is not easily diagnosed from this radiograph. Even though this picture should be repeated when the patient is stable and brought to the radiology department later, this is basically a good survey film.

This is a repeat of the patient in radiograph #15 above. The patient has been taken off of the spine board and the AP pelvis repeated. Does this radiograph meet the diagnostic criteria for the AP projection of the pelvis?

The patient is well centered and both hip joints are included. The entire hip bones, both hip joints, and proximal femurs through the lesser trochanter are demonstrated. This follow-up to the portable radiograph shows the pelvic ring fracture in good detail. Notice the left acetabulum is involved and the left femur is unaffected. The sacroiliac joints are well demonstrated as is the soft tissue structures like the urinary bladder and visualized bowel. The radiographic exposure technique is adequate for the posterior and anterior elements of the pelvis. The AP pelvis view alone is not always sufficient to determine stability of the pelvis so a CT scan will no doubt be done to further characterize the extent of injury. This radiograph meets diagnostic standards for the AP pelvic projection.

This patient was brought to a local emergency room on a spine board after suffering acute trauma. The patient was a pedestrian who was hit by a motor vehicle. Does this radiograph meet the diagnostic criteria for the portable AP projection of the pelvis?

This radiograph tells the story of a life threatening situation. Under great pressure to perform the technologist has done a fine job of not clipping any anatomy on this portable radiograph. Notice that the part is well centered and all of the required anatomy is present. Because the technologist performed professionally and did achieve the diagnostic criteria crucial interventional time was saved. Based on this radiograph A CT scan of the chest, abdomen, and pelvis was performed immediately, and interventional radiology called upon to manage uncontrollable hemorrhaging. The radiographic technique shows good bone detail so the fracture of the sacrum and femur are also identified (arrows). Further radiographic imaging was required to determine pelvic stability and possible injury to soft tissue structures. The exposure technique was adequate for visualizing multiple injuries of the pelvis and right femur.

This patient was brought to a local emergency room on a spine board after suffering acute trauma. The patient was a pedestrian who was hit by a motor vehicle. Does this radiograph meet the diagnostic criteria for the portable AP projection of the pelvis?

The magnitude of injuries seen on this radiograph, like the previous one, tells the story of a serious life threatening situation. Good diagnostic radiography is important to the treatment of all trauma patients and increases chance of survival. Here we see a right hip dislocation and the entire right hemi-pelvis is shifted. Separation of the symphysis pubis (a condition called diastases) may indicate significant injuries to structures within the true pelvis. Symphysis widening seen on this radiograph may suggest injury to the urethra and/or urinary bladder. An optimal radiograph would have included the entire proximal left femur, iliac wing, and inferior ramus of the right pubis bone. Always place patient identification marker in an area that does not obstruct anatomy. The metal strap from the spine board also obscures anatomy. Radiographic technique is excellent. This radiograph should be repeated if plain films like an inlet, outlet, or Judet views are requested. It will not need repeating if a CT scan of the pelvis is added to the trauma screen.

This is also a trauma patient who presented with the right hip in external rotation. Does this radiograph meet the diagnostic criteria for the AP projection of the pelvis?

When a trauma patient presents with external rotation of the lower extremity the technologist should not internally rotate the hip. External rotation of the leg following trauma often indicates a fracture of the proximal or distal femur, or acetabulum. This radiograph reveals a complex pattern of injury: fracture of the right acetabulum, right pelvic ring, and both ilium wings. Thes right iliac wing is clipped as is a portion of both iliac crests. The external rotation of the right hip is to be expected and is not indicative of poor position on the part of the technologist. I suspect that magnification due to increased OID may be the reason for clipping the pelvis; another cause is failure to properly center the part. Both iliac wings have fractures and are clipped due to positioning. In addition, this radiograph was not taken as a portable, so the technologist could have done several things to decrease the OID and get all of the part on the radiograph. Better centering of the part taking advantage of the entire film would reduce the chances of a positioning error. The exposure technique shows a well penetrated pelvis with good bone detail through the acetabula, pubis bones, and iliac wings, and sacrum permitting radiographic interpretation of the entire pelvis.

Give your critique of this radiograph taken post-operative following both internal and external fixation to stabilize the pelvis.

This is a good post operative radiograph because it demonstrates the entire pelvis. A portion of the left proximal femur and prosthesis is not demonstrated. Then again, it is not required to be entirely included unless the left hip is also specified in the exam request. If the left hip is specified along with the pelvis a separate left hip should be taken to include the entire prosthesis. This radiograph does adequately demonstrate the surgical fixations of the pelvis. The field of view extends from above the iliac crests to below the lesser trochanters. The pelvis is not significantly rotated although the sacrum, which is not anatomically midline with the pubic symphysis, is due to traumatic displacement not positioning. The radiographic exposure technique displays good penetration of bone and proper contrast between metal fixation devices and bone. Soft tissue structures such as the urinary bladder and bowel gas presentation is balanced with good bone detail.

Give your critique of this portable AP pelvis radiograph to evaluate the hip prosthesis. Could anything have been done to make this a better radiograph?

Is this not an ugly radiograph? The cause of this poor quality radiograph is that the technologist forgot to take a grid and decided to try and get by without it. A radiograph is a diagnostic tool and unless it meets diagnostic standards is fairly worthless. The technologist only need to remember that any part greater than 10 cm can produce enough scatter radiation to cause excessive fogging of the image. A grid must be used in situations where excessive scatter radiation that can fog an image occurs. A grid helps to clean up scatter by removing much of it, which results in higher radiographic contrast. Using high kVp to penetrate the pelvis causes scatter radiation, which lowers subject contrast. Using a grid removes a significant amount of scatter radiation which in turn yields higher subject contrast and better subject detail. Fixing the quality of the radiograph seen here is simple use a grid of at least 8:1 to clean up the scatter radiation fogging this image. This is the classical high kVp exposure without a grid (error). And what is funny about it is that if you do this, you will still have to return with a grid to repeat the radiograph. Think ALARA at all times and avoid these mistakes. The other problem with this radiograph is that the left acetabulum is not entirely included. Improper alignment of the patient caused tilt of the pelvis placing the right acetabulum below the left acetabulum. Good alignment is very important for post-operative imaging because it makes evaluation of symmetry more accurate.

Pelvic inlet/outlet

The pelvic inlet and outlet views are generally taken to supplement the AP pelvis view. The pelvic inlet is formed by two arching lines that begin posteriorly with the sacral promontory and extends anterolaterally as the arcuate lines and pectin on the superior pubic rami. The pelvic inlet is the opening into the true pelvis, which houses the urinary bladder and rectum in both genders, and the uterus in females. The pelvic inlet (brim) is formed posteriorly by the sacral promontory and extends along an oblique plane that passes through the arcuate line of the ilium, along the pecten pubis and pubic crest (a.k.a. linea terminalis). Within the true pelvis are the bladder, rectum, and portions of the urogenital organs.

This CT midsagittal view of the pelvis demonstrates the inlet and outlet of the true pelvis. The superior aperture or inlet is represented by a line drawn from the sacral promontory to the crest of the superior pubic ramus (white line). The inferior aperture or outlet is represented by a line drawn from the coccyx to the inferior pubic ramus (blue line). These two lines represent the boundaries of the true pelvis. Within the true pelvis in females from anterior to posterior are the urinary bladder (B), uterus (U), and rectum (R).

The inlet view is important because it can immediately identify narrowing or widening of the pelvic ring. Identifies posterior displacement of the pelvic ring, sacroiliac joint (SI joint), and/or rotation of the hemipelvis. Internal or external rotation of the hemipelvis, pubic diastasis or bone overlap, or subtle sacral fractures or impaction is better seen on the inlet view. The inlet view is taken with the patient supine and the x-ray beam angled 25-45 degrees caudal and perpendicular to the pelvic brim. The following are some determinations permitted by the inlet view:

• The degree of posterior displacement at the SI joint.
The degree of internal or external rotation of the hemipelvis.
• The degree of pubic diastasis or overlap.
• The presence of subtle sacral fractures or sacral impaction.

This pelvic inlet view of the pelvis demonstrates the importance of seeing the posterior element of the pelvic inlet along the sacral border. An area of the pelvis (circle) is magnified on the right to show a vertical fracture (arrow) of the pelvis that is not easily characterized using the AP pelvis view alone. The inlet and the outlet views better demonstrate posterior ring fractures and injuries involving the SI joints than the AP view alone.

The pelvic outlet bound by the sacrum/coccyx posteriorly, the symphysis pubis anteriorly, and flanked by the ischial tuberosities laterally. The primary purpose of the outlet view is to demonstrate the magnitude of vertical displacement of the hemipelvis. It presents the anterior ring superimposed on the posterior ring. Sacral foramina are better depicted on the outlet view than with the AP pelvis view. Additionally, some sacral and pubic rami fractures are better visualized on the outlet view than the routine AP pelvis view. Proximal or distal displacements of the ring are better appreciated on this view. The outlet view is obtained with the patient in the true AP position and the tube angled 45 degrees cephalic. The following are some determinations permitted by the outlet view:

• Can corroborate vertical displacement of the hemipelvis and visualize the SI joints.
• Demonstrates the sacral neural foramina better than the AP pelvis view.
• Some pubic fractures are better seen with the outlet view.

The femoral heads should be demonstrated on the outlet view because this projection can demonstrated anterior or posterior displacement of the hip joint. The 45 degree cephalic angulation will cast the shadow of an anteriorly displaced femoral head above that of the acetabulum and the shadow of a posteriorly displaced femoral head is cast below the acetabulum. The sacroiliac joints and anterior margin of the pelvic brim are well-demonstrated by the outlet view.

The pelvic outlet view demonstrates the pubic rami, obturator foramina, and anterior and posterior margins of the pelvis. The full view on the left demonstrates the anatomy demonstrated by this projection. On the right is a magnified area displaying the pelvic ring. Notice the borders of the posterior elements, mainly the sacrum (arrows) and SI joints are well defined. The anterior rim of the pelvic ring is also well defined (arrowheads) on this view.

This coronal CT image shows the partial structure of the pelvic ring. Notice the continuity of bone from the sacroiliac joints to the visualized portion of the superior pubic rami anteriorly. The pelvic brim is a solid structure that forms the opening into the true pelvis. Notice the soft tissues, especially the sigmoid and rectum seen in this image.

This inferior view of the pelvis shows the outlet at the inferior opening of the true pelvis. The pelvic outlet is bound posteriorly by the coccyx (arrow) and anteriorly by the inferior pubic rami. Strong ligaments bridge the opening but make an expandable space available for passage of the fetus during childbirth.

Does this radiograph meet the diagnostic criteria for the pelvic inlet projection of the pelvis?

This inlet view shows the right pelvic brim well as the arcuate line and pectin are well seen. However, the left portion of the ring is not in profile because the pelvis is slightly rotated. When accurately positioned the ischial spines are aligned with the pelvic brim and the sacrum and coccyx aligned with the pubic symphysis. The pelvis is slightly rotated to the left (left posterior oblique). To avoid rotation of the pelvis check the distance from the ASIS to the tabletop on each side of the pelvis to make sure they are equidistant. There appears to be no displacement of the ring accompanying the right acetabular fracture. The femoral heads and necks are seen in profile and demonstrate no dislocation of the femora. At least a 45 degree caudal angle should have been used to elongate the ring better. This view should not be repeated for positioning errors seen; the exposure technique is optimal.

This inlet view of the pelvis was taken following an AP view which revealed a pelvic ring fracture. Does it meet the diagnostic criteria?

The tube angle is much better than in radiograph #22. The patient is positioned in a true AP without rotation of the pelvis. There is good presentation of the pelvic ring a smooth contour of the ring on the right and irregularity on the left demonstrated by the white arrow. The left inferior pubic ramus that is fractured is also nicely demonstrated. The radiographic exposure technique shows a well penetrated sacrum (notice the vertical fracture of the left sacrum) and a well penetrated left acetabulum. Soft tissue structures like the urinary bladder and gas in the rectum are optimally visualized.

This patient had an unstable pelvic fracture involving the sacrum, as well as pubic rami fractures and left hip fracture. Does this post-operative inlet view meet the diagnostic criteria?

It is important with post-operative imaging that the entire pelvis is demonstrated. The pelvic brim is adequately demonstrated without rotation of the pelvis. However, the entire sacrum is not demonstrated. Demonstrating from L1 and the iliac crests through the inferior portion of the hip bones is required for this view. This patient suffered an unstable injury of the pelvis so the posterior pelvic elements must be seen in their entirety. Radiographic exposure is adequate. Repeating this projection to include the posterior pelvic region and the anterior portions of the pelvis should be included.

This inlet view was requested following an AP portable pelvis x-ray that revealed a left pelvic ring fracture. Does this radiograph meet the diagnostic criteria for the inlet pelvis view?

This radiograph does not meet the diagnostic criteria for several reasons. Among them are the failure to include the entire pelvis, and the other reason is inadequate penetration of the acetabula and proximal femurs. The tube angle is sufficient for demonstrating the pelvic inlet. We can see an obvious interruption of the pelvic ring on the left (arrow). The exposure technique does not penetrate the pelvic brim very well. A complete evaluation of the left pelvic ring is not possible based on this exposure technique. This radiograph should be repeated using more kVp to penetrate the pelvis. Also, increasing the SID will decrease the magnification seen on this radiograph. Including all of the pelvis and the sacrum is an essential requirement for a diagnostic inlet view. There appears to be fractures involving the left iliac wing, acetabulum, and proximal femur.

This radiograph was requested for pre-op evaluation of left pelvic ring, left acetabular fracture, and right pubic rami fractures. Does this radiograph meet the diagnostic criteria for the inlet pelvis view?

When positioning it is important to align the patient to the midsagittal plane as much as possible, especially when there is a known fracture. This is because comparison of the right and left hemipelvis will be made. Notice the patient is still on a slide board and the technologist did not align the midsagittal plane to the midline of the image receptor. The right acetabulum is lower than the left acetabulum. This makes comparing symmetrical parts more difficult. Another problem with this radiograph is that the superior part of the pelvis is clipped and there is excess inclusion of the femora inferiorly. Subject contrast, especially bone density is inadequate for this view. A more penetrated look at the acetabula, especially the left is needed. Repeat radiograph correcting positioning and technique issues is recommended.

Does this radiograph meet the diagnostic criteria for the inlet pelvis view (patient history is acute trauma)?

This is a good outlet view even though the pelvis is slightly rotated to the left (sacrum/coccyx is not aligned with symphysis pubis) Notice the S.I. joints and sacral foramina are profiled. We can see the entire pelvis superiorly and inferiorly and the lesser trochanters of the proximal femora. The anterior and posterior elements of the pelvic brim are well delineated. The obturator foramen (superior and inferior pubic rami, and ischium) are opened and well visualized as are iliac spines and coccyx. The radiographic exposure technique provides excellent bone and soft tissue detail. This is an excellent radiograph that meets diagnostic criteria.

As a follow-up to trauma, this outlet view was taken along with the inlet view. Does it meet the diagnostic criteria for the outlet view?

What is good about this radiograph is that it has minimal to no rotation of the pelvis. The coccyx and ischial spines are appropriately demonstrated. The fracture through the left acetabulum is also well visualized due to the excellent exposure technique selected. While this radiograph was not repeated because it was known there is no fracture involving the superior pelvis wings and crest, these structures should have been included. Also the x-ray tube could be angled a bit more cephalic (about 45 degrees is recommended), which would display more of the coccyx inferior to the pubic symphysis. Otherwise this is a great radiograph.

This radiograph was taken to evaluate the pelvis, especially the internal fixation of the sacrum post-operatively. Does it meet the diagnostic criteria for the outlet view?

Whenever a radiograph is made the patient should be properly position so that the image is an acceptable diagnostic tool useful to treat a medical condition. We know this is a post operative radiograph to evaluate internal and external fixation of the pelvis. Notice the patient is slightly rotated to the left causing the sacrum to not be aligned with the symphysis pubis. This may be because the patient was uncomfortable following surgery and the technologist did not want to add to the patient’s discomfort by properly positioning them. Because of this the left obturator foramen is almost closed and the sacroiliac joints can not be properly evaluated. When properly positioned the left hip prosthesis may obstruct the anterior portion of the pelvic brim. The surgeon may request inlet and outlet views to better visualize the pelvic brim. Radiographic exposure technique shows graininess of the image or noise caused by too little mAs and high kVp. When this view is repeated to correct the positioning error also correct the technique using the 50/15 rule.

Judet view

Sometimes an injury involving the acetabulum is in question and a better presentation of the acetabula is helpful. An acetabular fracture may occur in addition to a pelvic ring fracture and must be distinguished from pubic rami and iliac wing fractures. In such case the acetabular fracture must be discretely analyzed. The plain film studies of choice for this are the Judet views (so named because Judet stressed the use of these views for trauma imaging. The patient is positioned with the midsagittal plane 45 degrees to the tabletop and the central ray perpendicular to the image receptor. Usually both oblique views are made unless specified as a unilateral examination. The Judet views are internal and external oblique views, which are very useful for visualization of nondisplaced acetabular fractures.

To fully appreciate why the Judet view is sometimes ordered let’s look at a real clinical case involving an acetabular fracture. Three radiographs are presented below the first of which is the standard AP pelvis radiograph (A). If you look closely at it you may see the fracture fragment through the right femoral head which is magnified (B). The Judet view which is taken with a perpendicular x-ray beam and the patient turned 45-degrees into the left posterior oblique position. This view demonstrates the fracture fragment from the posterior acetabulum in profile, which confirms the diagnosis.

Often the AP view does not demonstrate a pelvic fracture of the acetabulum sufficiently to characterize it. The physician may request Judet views. Dr. Judet stressed the importance of these views referencing a similar type of fracture seen in the radiographs above. Radiograph (A) demonstrates a hard to see fracture. Radiograph (B) magnified through the right acetabulum ill defines an acetabular fracture. Radiograph (C) is a LPO Judet view demonstrating the fracture of the posterior acetabulum not so easily seen on the AP view. These three radiographs demonstrate the importance of the AP view and follow-up views like the Judet view for suspected pelvic fracture of the acetabulum.

The judet views demonstrate both acetabula and provide useful evaluation for suspected acetabular fractures. Adding both internal and external oblique views (45 degree obliques) a detailed look at the acetabulum to better visualize nondisplaced and displaced fractures is obtained. The entire pelvis is also imaged to display the iliac wing of the side down and SI joint and opened obturator foramen of the side up. For the Judet view the patient is turned so that the mid-coronal plane is turned 45-degrees to tabletop. The tube is positioned vertical to the film. The structures demonstrated are: both acetabula with side up being profiled, the femoral neck and greater trochanter of side up is profiled, and the entire ilium of side down is seen. Both sides are generally taken, the left and right posterior obliques.

These two radiographs demonstrate the Judet views which are 45-degree posterior oblique views of the pelvis. They are so named because Dr. Judet stressed the importance of these views in evaluating the pelvis, especially the acetabulum. The left radiograph is the RPO view. It demonstrates a fracture of the right acetabulum very well. The radiograph on the right shows the LPO view, which profiles both acetabula.

Judet views help describe fractures involving the innominate bone and acetabulum. It is important to demonstrate fractures involving the anterior or posterior column, or the anterior or posterior wall of the acetabulum. The AP view alone may miss some fractures in this area and only weakly characterizes them when seen.

This CT axial image through the mid acetabular region shows the various proposed columns of the hip bone. A reference line (rl) is used to define the anterior (AW) and posterior (PW) walls of the acetabulum lateral to it. A line through the mid-coronal plane gives a division of the hip into an anterior column (AW) and a posterior column (PC). These landmarks for describing fractures was defined by Letournel and Judet, however, current understanding of structure and function of the hip bone is continually defining descriptive landmarks.

This radiograph was taken to evaluate the right hip following an known fracture seen on the AP pelvis view. Does this radiograph meet the diagnostic criteria for the Judet view?

Overall, this is a good Judet view because it shows the left acetabulum in profile, and the right hip dislocation. This was the area of concern on the AP pelvis view. The ipsilateral hip is seen in profile as well. Not including the greater trochanter of the right femur unfortunately is a positioning error. Whether or not it should be repeated depends on what was demonstrated on the AP view of the pelvis, and also on presentation of the right proximal femur on the RPO Judet view. Between the three views it may not be necessary to repeat this view. Bone detail is excellent and there is sufficient penetration of structures to evaluate for a fracture or dislocation.

This Judet view was taken to evaluate the pelvis following an AP view. In what ways does this radiograph meet the diagnostic criteria?

All anatomy required for the Judet view is included on this radiograph. This radiograph meets the diagnostic criteria for positioning of the pelvis; however, this radiograph displays high contrast, which is not optimal for imaging the pelvis. A well penetrated right acetabulum is demonstrated: however, the left acetabulum is slightly underpenetrated. Because the left hip is close to the film there is good subject detail. Notice the fracture of the left iliac wing is in profile, but the high contrast exposure created burnout along the edge of the iliac crest. Exposure technique should be in the 75-85 kVp range for this view, which will give optimal bone penetration and good subject contrast.

Does this radiograph meet the diagnostic criteria for the Judet view, why or why not? Does it meet diagnostic standards?

To appreciate the critique of this radiograph we added a magnified view of the area over the right hip and right pelvic brim. Let me first say that this radiograph does not meet the diagnostic standards for the Judet view. Careful inspection will reveal that all of the required anatomy is presented on the radiograph. Also, the patient is properly positioned at about 45-degrees from the mid-coronal plane. However, the problem with this radiograph is the exposure technique. Notice the loss of detail along the right pelvic ring even on the magnified view. The fracture of the pelvis and free end is not at all well penetrated (arrow). Notice that the magnified view is darker because this is a digital image. We were able to window it to make it darker; however, we cannot make better subject contrast to show better bone detail. This radiograph does not need to be repeated since computed tomography may be needed to better characterize this fracture. Certainly, with digital imaging capabilities, this is an acceptable radiographic exposure technique.

Does this radiograph meet the diagnostic criteria for the Judet view to evaluate the acetabula, why or why not? Be sure to comment on the technique and positioning.

The positioning of the patient is good. Both acetabula are demonstrated. The part is well centered although the crest of the left ilium is partially clipped. The left inferior pubic ramus and ischial tuberosity is entirely visualized. The head, neck, and acetabulum of the side up (left) is well demonstrated. The side down (right) shows the femur in extreme external rotation. This has foreshortened the right femoral neck making its evaluation minimal. Neutral positioning or slight internal rotation of the hip is recommended as long as the patient does not have a hip fracture. Otherwise, the ‘as is” position of the leg is acceptable for any side injured. Radiographic exposure technique adequately displays the required anatomy. There is good bone penetration through the acetabula with good bone detail.

Radiographic Imaging of the Hip Joint

The hip joint is formed by the hip bone and the proximal femur. In the United States each year about 280,000 persons fracture their hip, more than 90% occur in the age 60+ age group. Hip fractures are more common in older women, one in three women compared to one in six men. The main contributor to hip fractures is osteoporosis. Osteoporosis is a bone loss disease cause by a reduction in mineral density of bone. Calcium in particular is a mineral that is stored in bone skeletal tissue; it gives bone its hardness. Bone tissue forms the frame of the body; however, it is not static like the foundation and walls of a building. Bone tissue is made of living cells called osteocytes that carry out metabolic functions. Too perform their functions, osteocytes have oxygen and nutritional needs just like other cells of the body such as liver and heart cells. To support the body’s frame, bone cells deposit calcium into bone and release calcium when needed for muscle activity. Bone fragility due to bone loss puts men and women at risk for fracture of the hip. It is estimated that about 34 million Americans have a status of low bone mass, a condition called osteopenia, which is a precursor to osteoporosis, and 10 million have osteoporosis.

What we know about osteoporosis today is being used to lower the risks of associated bone fractures. Informing the public about the causes of osteoporoses that include aging, smoking, family history, and low lifetime ingestion and absorption of calcium help individuals to manage their specific risks. Women are especially at risk for bone mass loss during the years following menopause. Decreased estrogen levels can cause as much as 50% of the trabecular bone and up to 30% of cortical bone. This subjects postmenopausal women to high risk of hip and other bone fractures. Understanding risks and consulting with a physician for preventive treatment against osteoporosis is effective. Diagnostic testing such as bone densitometry (DEXA scanning) is also available as a screening tool.

These two radiographs demonstrate two common types of fractures seen in the proximal femur. Radiograph A on the left demonstrates a fracture of the femoral head (arrow). Radiograph B on the right demonstrates an intertrocanteric fracture that has displacement of the lesser trochanter. Both of these types of fractures can result from trauma, especially in older adults with bone mass loss due to osteoporosis.

Fractures of the hip also occur in children, most often from trauma such as being struck by an automobile as a pedestrian. Concomitant injuries like to the head, thorax, and spine are high in children and adults. Hip fractures, femur fractures and the like occur in anatomical location relative to the age or height of the child when injured. In children, hip dislocations are more common than hip fractures. Young children are still undergoing bone development transitioned from a cartilaginous model. The process is called endochondrial bone growth where the cartilage frame is replaced by bone. In young children the acetabulum is composed of a significant amount of cartilage that gives it flexibility hardened bone does not have.

Some adults suffer chronic hip pain because of osteoarthritis (OA) and rheumatoid arthritis (RA). Degenerative joint disease (DJD) also called osteoarthritis is the most common type of joint disease. DJD has many causes with aging being the primary culprit although it is multifactorial. Osteoarthritis occurs in both men and women and can develop as a result of joint trauma, developmental disorders, and genetic disease. Rheumatoid arthritis is an inflammatory disease that causes joint disfigurement, swelling, and chronic pain. It is more common in women, nearly 3 times more common in women than men. Nearly 1% of the population in the United States has some form of rheumatoid arthritis. In many cases the best remedy for both forms of arthritis is hemiarthroplasty or total hip arthroplasty (THA).

An accurately positioned AP hip radiograph will show the ischial spine aligned with the pelvic brim and the sacrum and coccyx aligned with the pubic symphysis. When properly positioned the obturator foramen is open. The position of the femur is also important and should be internally rotated 15-20 degrees. When properly rotated the femoral neck is not foreshortened. The greater trochanter is seen laterally in profile, and the lesser trochanter is superimposed on the femoral neck. This is what is seen when the leg is internally rotated properly with an imaginary line connecting the femoral epicondyles is parallel with the tabletop. Quite obviously the technologist should not force internal rotation of a potentially fractured or dislocated hip. Doing so may result in injury to the blood supply and nerves in the area of injury. Patients likely to have a fracture or dislocation present with the leg in external rotation in addition to pain and loss of function. The following structures should be seen within the collimated field of view:

These three radiographs demonstrate the proper positioning and required anatomy for the AP hip radiograph. The radiograph on the left is of a child as you can see from the incomplete union of the ilium, ischium, and pubis that form the acetabulum. The epiphyseal plates of the femoral head and greater trochanter indicate the patient is a child. The middle radiograph shows a total hip prosthesis and its proper positioning with the correct amount of anatomy to be demonstrated. The radiograph on the right shows an adult hip with a fused acetabulum. Notice that in all three radiographs the proper anatomy is demonstrated and the radiographic exposure is proper for the presentation of the patient. These are optimal radiographs that meet all diagnostic criteria stated in the paragraph above.

This radiograph was taken for acute trauma involving a fall. The patient presented in extreme pain with an externally rotated leg. Does it meet the diagnostic criteria for the AP hip projection?

This is a good radiograph of the left hip. The normal angle between the axis of the femoral shaft and neck of the femur is 120-130 degrees. Here we see the angle is more acute approaching 90 degrees. Whenever a trauma patient presents with an externally rotated leg it should not be manipulated for imaging. The technologist properly positioned the pelvis as the obturator foramen is open and the pubis and ischium are correctly