Robert G. Dussault

Radiographic measurements of dysplastic adult hips.

Abstract Hip dysplasia is a not uncommon feature in adults and can vary from subtle acetabular dysplasia to complex sequelae of developmental dysplasia of the hip. This review article describes the most useful radiographic measurements used to evaluate the adult hip. The frontal projection of the pelvis permits measurement of the center-edge angle (CE angle) and ”horizontal toit externe” angle (HTE angle), both of which assess the superior coverage of the acetabulum. The femoral neck-shaft angle (NSA) is also measured on this view. The false profile radiograph of the pelvis is described. It allows measurement of the vertical-center-anterior angle (VCA angle), which determines the anterior acetabular coverage and detects early degenerative hip joint disease. When surgery is contemplated, computed tomography (CT) is useful to better determine the anterior acetabular coverage by use of the anterior acetabular sector angle (AASA), and the posterior acetabular coverage by use of the posterior acetabular sector angle (PASA). CT also permits measurement of femoral anteversion. These measurements are particularly useful in the evaluation of acetabular dysplasia and for the preoperative assessment of the dysplastic hip.

The MR appearance of cruciate ganglion cysts: a report of 16 cases

Intra-articular ganglion cysts arising from the cruciate ligaments are unusual lesions, there being only nine previously reported cases. We report 16 cases and describe their MR appearance. Nine ganglia originated from the posterior cruciate ligament, most often appearing as well-defined multilocular lesions. The seven ganglia arising from the anterior cruciate ligament most often appeared as fusiform cystic lesions extending along and interspersed within the fibers of the ligament. Although uncommon, intra-articular ganglion cysts arising from the knee appear to have a distinctive MR appearance which should allow their correct diagnosis.

IMAGING OF THE KNEE: Current Status

This article reviews the variety of imaging modalities that are currently being used to evaluate the knee. Nuclear scintigraphy is discussed with emphasis on prosthesis abnormalities. Sonography is discussed with regard to the evaluation of popliteal masses. The uses of computed tomography, especially in the evaluation of the tibial plateau fracture, are discussed, and the role of fluoroscopy, computed tomography, and sonography in image-guided needle procedures are reviewed. Emphasis is placed on the role of MR imaging in knee imaging, with attention to internal derangements, bursal and capsular pathology, and other assorted intra- and extra-articular disorders. The focus of this article is to review the wealth of information that may be obtained by using these imaging modalities.

Retrospective evaluation of graded stress examination of the ankle.

Stress radiography of the ankle commonly is used to evaluate talar tilt in patients with a history of inversion ankle sprains. Manual and instrumented procedures have been variously described in the literature. No reports have documented normative talar tilt as measured using the Telos ankle stress device in a large clinical population. In addition, little has been done to examine the value of using graded displacement forces compared with a single displacement force. Bilateral Telos examinations from 113 consecutive patients taken during a 4-year period were evaluated for this study. No measurable talar tilt was observed in 65.8% of the ankles in this study. Talar tilt ranged from 1.7 ° to 24.9 ° in injured ankles. In patients with quantifiable talar tilt, all had greater talar tilt at the 15 kPa force than at all other forces. Because of the variability in talar tilt in injured and comparison ankles, clinical conclusions regarding injury severity cannot be made on measured talar tilt alone. The analysis suggests that inversion stress examination is helpful in documenting gross talar instability, but the discriminant value of the procedure to determine the anatomy and severity of lateral ligament injury is tenuous.

Imaging of bursae around the shoulder joint

Abstract The authors present a review of the anatomy of the major bursae around the shoulder joint and discuss the use of the different imaging modalities which demonstrate their radiologic features. The calcified subacromial-subdeltoid bursa has a characteristic appearance on plain radiographs. When inflamed it can be visualized by ultrasound and magnetic resonance imaging. Calcific bursitis may involve the subcoracoid bursa. This bursa may mimic adhesive capsulitis of the shoulder or complete rotator cuff tear when injected inadvertently during shoulder arthrography. Less well known are three coracoclavicular ligament bursae. These are also subject to calcific bursitis and have a typical radiologic appearance.

Fatty marrow conversion of the proximal femoral metaphysis in osteonecrotic hips.

To determine whether fatty marrow conversion of the proximal femoral metaphysis is related to osteonecrosis of the femoral head using a marrow conversion index ([signal intensity of the proximal femoral metaphysis/signal intensity of the greater trochanter] x 100 in T1 weighted magnetic resonance images), a case control study was conducted on 42 osteonecrotic hips in 28 patients. The 28 patients (42 osteonecrotic hips) were matched with 84 control patients (84 normal hips) for gender, age (5-year range), and time of presentation (1-year range). The marrow conversion index was measured in each hip studied. The index was 90.2% (standard deviation, 8.2%) in osteonecrotic hips and 75.1% (standard deviation, 9.1%) in matched controls. By conditional logistic regression, a 5% increase in the index was associated with 3.6 times increase of the odds ratio of osteonecrosis and a 10% increase with a 12.9 times increase of the odds ratio. The marrow conversion index, which reflects the ratio of fatty marrow conversion of the proximal femoral metaphysis to that of the greater trochanter measured on T1 weighted magnetic resonance images, is increased in osteonecrotic hips.

Fracture of the os peroneum and rupture of the peroneus longus tendon as a complication of diabetic neuropathy

The patient is a 48-year-old woman with a longstanding history of insulin-dependent diabetes mellitus with clinical evidence of neuropathy. She presented with nontraumatic swelling of the lateral aspect of her left foot, which on the initial plain film demonstrated a transverse lucency representing a subacute fracture of the OP (Fig. 1). There was also an associated fracture of the cuboid bone seen only on the lateral view. Increased uptake in the same region on a 99Tebone scan was consistent with fracture. Follow-up radiographs 6 weeks later showed progressive healing of the OP fracture. However, the OP had migrated several centimeters proximally, lateral to the os calcis (Fig. 2). The diagnosis of a ruptured PLT, just distal to the OR was confirmed and diffuse partial tears of the remaining tendon were shown with MRI (Fig. 3).

Plain film evaluation of degenerative disk disease at the lumbosacral junction

ObjectiveDiagnosing degenerative disk disease (DDD) at the lumbosacral junction (LSJ) on plain films is often difficult, compared with other disk levels. The purpose of this study was to determine whether criteria for diagnosis of DDD at the LSJ can be established for plain films.Design and patientsWe retrospectively reviewed 100 lumbar MRI scans of patients who also had lumbar plain films. Using MRI as the reference standard, the LSJ was classified as normal (n=35) or exhibiting mild (n=45) or severe (n=20) DDD by two radiologists using accepted criteria. Measurements were performed on the plain films by two other radiologists and the average measurements were tabulated according to the three categories of DDD defined by MRI. Plain film measurements included the anterior and posterior disk heights (ADH, PDH), Farfan’s ratio, determined by adding ADH to PDH and dividing that number by the measured antero-posterior (AP) length of the inferior end plate of L5 [(ADH+PDH)/AP length of L5], and lumbosacral angle (LSA). Subsequently, five additional radiologists interpreted the radiographs by visual inspection only, for DDD at the LSJ, both before and, several weeks later, after being provided with the quantitative data for normal versus DDD.Results and conclusionThere was a statistically significant difference between normal disk and increasing severity of DDD on radiographs using the parameters of PDH and Farfan’s ratio. There was no statistically significant difference regarding ADH or LSA. Diagnostic accuracy by visual inspection was not significantly altered using the quantitative data for interpretation of DDD (68% correct before, 69.5% correct after). Analysis of results indicates that PDH is the most reliable and easily used criterion for detection of DDD at the LSJ. A PDH ≤5.4 mm on plain lateral film indicates DDD; PDH ≥7.7 mm indicates the absence of DDD on plain film.

Acute knee trauma: how many plain film views are necessary for the initial examination?

Abstract Objective. To determine whether anteroposterior (AP) and lateral views of the knee are equivalent to four views in acute fracture detection. Design. Three musculoskeletal radiologists retrospectively interpreted the plain film knee examinations of each patient, establishing ground truth for the presence or absence of a fracture. Cases were presented to four masked senior radiology residents twice – once as a two-view study and again as a four-view study – with 4 weeks separating the two reading sessions to minimize recall bias. Sensitivity, specificity, and diagnostic performance were calculated. Patients. Ninety-two patients presenting to the emergency department with acute knee trauma were evaluated with at least a four-view plain film examination. Results and conclusions. Mean sensitivity for fracture detection using four views (85%) was significantly higher than that using two views (79%). Mean specificity and receiver operating characteristic curve areas were not significantly different using two or four views. Four views are more sensitive than AP and lateral views alone in detection of acute knee fracture.

Magnetic resonance imaging of the wrist

MR imaging of the wrist has the unique capability of simultaneously demonstrating bone and soft tissue structures. Its exquisite sensitivity for detecting bone marrow edema makes it and ideal screening tool for diagnosing radiographically occult osseous injuries and areas of AVN. This, together with its ability to provide a comprehensive, non-invasive assessment of the ligaments, tendons, nerves, and components of the TFC make MRI a very powerful tool for evaluating patients with wrist pain of uncertain etiology. Its exact role in the work-up of these patients has not been entirely established, but with further advances in technology and the radiologists understanding of wrist anatomy and pathology, MRI is assuming a more central role in this clinical setting.