Donald Resnick

Magnetic resonance appearance of sacral insufficiency fractures.

Insufficiency fractures of the sacrum are a commonly recognized form of stress fracture typically occurring in elderly patients. As such patients usually present with low back pain, MR imaging is often performed initially as a means of evaluation. We present 5 patients with sacral insufficiency fractures imaged with MR. Metastatic disease was a leading clinical suspicion as all patients were elderly and three had known primary neoplasms. T1-weighted sequences demonstrated bands of decreased signal intensity, usually paralleling the sacral aspect of the sacroiliac joints and occasionally occurring as a horizontal band across the sacral body. Four of five patients underwent further evaluation with computed tomography (CT) or nuclear bone scanning, which confirmed the diagnosis of sacral insufficiency fracture. We conclude that MRI is sensitive but not specific in detecting sacral insufficiency fractures. As MR imaging is rapidly becoming the method of choice for evaluating back pain, it is important to consider this diagnosis in elderly persons.

The ‘tilt deformity’ of the femoral head in osteoarthritis of the hip: A poor indicator of previous epiphysiolysis

Apparent superomedial migration of the femoral head producing the tilt deformity is the most frequent pattern of femoral head deformity in osteoarthritis of the hip. Previous reports have suggested a relationship to minor degrees of epiphysiolysis in the adolescent. Radiological and pathological examination of femoral heads obtained at the time of total hip replacement for osteoarthritis demonstrate characteristic abnormalities accompanying the tilt deformity. It would appear that, in most patients, this pattern of femoral head migration results not from epiphysiolysis but from a remodelling process in the osteoarthritic joint.

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.

Synovial cysts of the hip joint and iliopsoas bursitis: A spectrum of imaging abnormalities

Synovium-related soft tissue disease around the hip constitutes a spectrum ranging from isolated iliopsoas bursitis to pure articular synovial herniations without bursal involvement. The clinical, pathologic, and radiographic features of these entities are discussed as they pertain to the variety of underlying disorders which predispose to their occurrence. Nine case reports are utilized to illustrate the variable clinical and radiographic presentations which may be encountered. Based upon these cases as well as those in the literature, an imaging algorithm has been developed which should eliminate unnecessary studies and allow prompt and accurate diagnosis.

MR imaging findings of pyogenic bacterial myositis (pyomyositis) in patients with local muscle trauma: illustrative cases

Pyogenic myositis (pyomyositis) represents a bacterial infection of muscle, usually caused by Staphylococcus aureus that is endemic in tropical regions. Pyomyositis commonly affects patients who are immunocompromised or who have underlying chronic disorders. Lower extremity localization of infection is typical. The most common pattern of disease, however, appears to be a solitary abscess in the quadriceps musculature. Delay in accurate diagnosis is frequent and clinical deterioration can be precipitous. In view of the high associated morbidity, early imaging to detect, localize, and define disease extent is important. Magnetic resonance imaging (MRI) plays a key role in the definitive diagnosis of pyomyositis. This article provides a pictorial illustration of the spectrum of MRI findings associated with pyogenic myositis.

Glenoid hypoplasia and its relationship to instability.

Abstractu2002Glenoid hypoplasia, or dysplasia of the scapular neck, is usually a bilateral and symmetric finding. Associated findings include hypoplasia of the humeral head, elongation of the glenoid cavity, and alterations in the shape of the coracoid or clavicle. Glenoid hypoplasia has been reported sporadically in the radiologic literature, but the condition may be more frequent than previously thought. In this paper, we discuss the radiographic findings of glenoid hypoplasia and explore the possibility of an association between glenoid hypoplasia and shoulder instability.

Isolated or dominant lesions of the patella in gout: a report of seven patients

Isolated or dominant osteolytic lesions of the patella are an unusual manifestation of gout. We present seven patients who had such patellar lesions unilaterally (six patients) or bilaterally (one patient) and analyze the radiologic characteristics to determine whether they can be differentiated from those of other osteolytic lesions of the patella. The lesions were uniformly characterized by a geographic pattern of bone destruction in the superolateral aspect of the patella. Five lesions were each accompanied by a peripatellar soft tissue mass, four of which contained calcification. It therefore appears that an osteolytic lesion of the superolateral portion of the patella, especially when associated with a peripatellar calcified soft tissue mass, should alert one to the possible diagnosis of gout. Awareness of this possibility may obviate the need for invasive diagnostic procedures.

Comparison of the osteoblastoma in gnathic and extragnathic sites

A comparative analysis of extragnathic and gnathic osteoblastomas showed that the lesion was similar clinical, radiologic, and histologic features in these two sites. Osteoblastomas in both areas most commonly present as painful swellings and appear radiographically as lucent or sclerotic lesions, depending on the degree of calcification. The typical histologic appearance is of a highly vascularized stroma with osteoblasts and abundant trabeculae of osteoid and immature bone in various degrees of calcification. These lesions are most often treated conservatively by curettage or local excision. The results of this comparison indicate that oral and maxillofacial surgeons can draw on the wider experience of other types of surgeons when treating this rare lesion.

What happens to the triangular fibrocartilage complex during pronation and supination of the forearm? Analysis of its morphology and diagnostic assessment with MR arthrography

Objective: To evaluate the dynamic morphologic changes of the triangular fibrocartilage complex (TFCC) during pronation and supination of the forearm using high-resolution MR arthrography in cadavers and to evaluate the impact of these changes on the diagnostic assessment of the normal and abnormal TFCC. Design and specimens: High-resolution MR arthrography of 10 wrists of cadaveric specimens was obtained in maximum pronation, in the neutral position, and in maximum supination of the forearm. The structures of the TFCC were evaluated by two musculoskeletal radiologists and correlated with anatomic sections. The position of the forearm that allowed the best visualization of normal structures and lesions of the TFCC was determined. Results: The shape and extent of the articular disc as well as the radial portions of the radioulnar ligaments did not change with pronation and supination. The articular disc was horizontal in the neutral position and tilted more distally to align with the proximal carpal row in pronation and supination. The fibers of the ulnar part of the radioulnar ligaments (ulnar attachment of the articular disc) revealed the most significant changes: their orientation was coronal in the neutral position and sagittal in positions of pronation and supination. The ulnomeniscal homologue was largest in the neutral position and was reduced in size during pronation and supination. The extensor carpi ulnaris tendon was centered in its groove in the neutral position and pronation. In supination this tendon revealed subluxation from this groove. The dorsal capsule of the distal radioulnar joint was taut in pronation, and the palmar capsule was taut in supination. The preferred forearm position for analysis of most of the structures of the TFCC was the neutral position, followed by the pronated position. The neutral position was rated best for the detection of ulnar and radial detachments of the TFCC, followed by the pronated position, except for two central perforations of the TFCC which were best seen with supination. Conclusion: The articular disc and the surrounding radial portions of the radioulnar ligaments form a rigid, unified complex with the radius without change in their shape in positions of pronation and supination of the forearm, while the ulnar attachment of the TFCC shows important dynamic changes. The neutral forearm position is the best position to analyze both the normal and the abnormal TFCC.

Cystic angiomatosis: case report and review of the literature

Abstractu2002The objective of this article was to offer a better characterization of the typical clinical presentation, radiologic findings, histology, treatment approaches, and differential diagnosis of cystic angiomatosis, a rare condition of which previous reports have been confusing because of unclear diagnostic criteria, different classifications, and variations in terminology. A case report using the improved imaging techniques of computed tomography scanning is presented in addition to an analysis and review of the previous literature, which relied heavily on plain film radiography, biopsy, and necropsy for diagnosis. A case report of a 26-year-old man initially symptomatic at age 12 is presented. Although a rare condition, cystic angiomatosis must be considered in pediatric and young adult patients presenting with diffuse, multifocal, cystic skeletal lesions, with or without visceral involvement.