Guerdon Greenway

MR appearance of idiopathic synovial osteochondromatosis.

Objective A retrospective review of the MR examinations in 21 patients with idiopathic synovial osteochondromatosis (ISO) was performed to determine its MRI characteristics. Materials and Methods Twenty-one patients diagnosed with ISO had undergone MRI prior to surgery. The MR images were retrospectively evaluated for configuration and extent of lesion as well as for signal characteristics. Results Three distinct MR patterns were seen in ISO: A—lobulated homogeneous intraarticular signal isointense to slightly hyperintense to muscle on T1-weighted images and hyperintense on T2-weighted images (n = 3); B—pattern A plus foci of signal void on all pulse sequences (n = 17); and C—features of pattern A and B plus foci of peripheral low signal surrounding central fat-like signal (n = 2). The foci of signal void in pattern B and C corresponded to areas of calcification and the foci of peripheral low signal surrounding central fat-like signal in pattern C corresponded to areas of ossification. Conclusion The MR appearance of ISO appears sufficiently unique to allow its differentiation from other causes of intraarticular pathology.

Carpal Tunnel Syndrome With Cystic Bone Lesions Secondary to Amyloidosis in Chronic Hemodialysis Patients

Carpal tunnel syndrome (CTS) is increasingly recognized in patients undergoing chronic hemodialysis. Although the etiology remains obscure, angioaccess-related vascular engorgement and edema, and ischemic neuropathy are two likely possibilities. Amyloidosis is a relatively rare cause of CTS and had previously been thought to occur almost exclusively in patients with multiple myeloma. We report seven patients on chronic hemodialysis who developed CTS and were shown to have amyloid deposition within the synovium. Amyloid was demonstrated by characteristic staining with Congo red on polarizing microscopy and confirmed by electron microscopy. Six patients also exhibited radiolucent carpal bone cysts which were histologically shown to be due to bone replacement by an amyloid-positive synovitis. The average age of the patient and time on dialysis were 59.1 and 7.9 years, respectively. Serum and urine immunoelectrophoresis and bone marrow aspirates showed no evidence for plasma cell dyscrasia in six patients, while one patient did manifest a monoclonal IgA spike. Autopsies in three patients and liver biopsy in another showed no other evidence for disseminated amyloid. These hemodialysis patients exhibited a unique syndrome of CTS, lytic lesions of the carpal bones, and amyloid deposition in the synovium and within the bone cysts.

Juxtaacetabular ganglionic (or synovial) cysts: CT and MR features

Radiographic findings include supraacetabular bone erosions, subchondral acetabular cysts, soft tissue masses with or without radiolucent inclusions representing nitrogen gas, joint space narrowing, and abnormal hip configuration. Associated tears of the acetabular labrum were confirmed by arthrography in two patients. Computed tomography and magnetic resonance imaging afforded improved delineation of soft tissue ganglia and their relationship to the acetabular bone, labrum, and hip joint. We report our experience with seven patients in whom various imaging examinations clearly documented the presence of soft tissue cystic lesions adjacent to the acetabulum; in six of the seven patients, significant clinical manifestations were evident in the affected hip. Such cysts, whether designated synovial or ganglionic in type, appear to be a frequently overlooked yet important cause of hip symptomatology.

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.

Diagnosis of tarsal coalition with computed tomography.

The value of computed tomography in the diagnosis of tarsal coalition is reported in six patients, five with talocalcaneal coalition and one with calcaneo-navicular coalition. The examination is technically easy to perform with the patient in the supine position and the knees flexed, and it allows simultaneous visualization of both sides. Because of these features and an ability to distinguish between bony and cartilaginous or fibrous fusion, computed tomography appears to be the method of choice for diagnosis of coalition involving talus and calcaneus. It is less useful in other types of coalition.

Dorsal Defect of the Patella (DDP): A Characteristic Radiographic Lesion

The dorsal defect of the patella (DDP) is a benign lesion with specific radiographic features. Seven cases of DDP are reviewed; all 7 lesions were identical in location and radiographic appearance. The characteristic lesion is round and lytic, with well-defined margins; it is located in the superolateral aspect of the patella adjacent to the subchondral bone. Arthrography reveals intact cartilage. DDP may occur in both sexes and may be bilateral. It is often found incidentally on radiographs ordered for acute trauma. Its etiology is not known. Differential diagnosis is also discussed.

Fluid-fluid levels in giant cell tumors of bone: Report of two cases

Fluid-fluid levels have been described in association with aneurysmal bone cysts, telangiectatic osteosarcoma, and a chondroblastoma. We report two cases of giant cell tumors of bone with fluid-fluid levels identified by computed tomography and, in one case, by magnetic resonance imaging. This finding has not previously been associated with giant cell tumors. The radiographic features of the fluid-fluid levels cannot be distinguished from those reported in other osseous neoplasms.

Chronic unreduced dislocations of the glenohumeral joint: imaging strategy and pathologic correlation.

Although the evaluation of acute or recurrent dislocations of the glenohumeral joint (GHJ) using routine radiography, specialized views, arthrography, and computed tomography (CT) has been extensively studied, methods of evaluation and osseous pathology of chronic unreduced GHJ dislocations are not well documented. In order to define such methods and pathology, we studied nine patients with chronic (greater than 6 months) unreduced anterior, posterior, superior, or central dislocations as well as one patient with a chronic rotator cuff injury; and seven scapular specimens, six with matching humeral specimens, with osseous abnormalities similar to those in the patients. We examined 15 additional scapular specimens with evidence of subluxation secondary to chronic rotator cuff injury. Standard, reformatted, and three-dimensional (3D) CT techniques were used to evaluate both the patients and the specimens. Our results indicate that characteristic alterations occur in the scapula and humeral head that are far more extensive than the classic Hill-Sachs, Bankart, and trough lesions. Such alterations occur at sites of osseous contact between the malpositioned humerus and scapula and are modified owing to prolonged adjustments made by the patients in an attempt to increase GHJ motion. Although routine radiography and specialized views are of some value, standard and 3D CT provide a more accurate analysis of the location and extent of the bone abnormalities and, as such, should be employed, particularly in the evaluation of patients in whom surgery is being considered.

Osteoma of soft parts

Osteomas of soft tissue are rare tumors. All previously reported cases occurred in the head, usually in the posterior tongue. We present two patients with soft-tissue osteomas in the thigh. Both masses were densely ossified and consisted of mature trabecular bone on computed tomography and magnetic resonance examination. Increased uptake of boneseeking radiopharmaceutical was found on scintigraphy. Histologically, mature lamellar bone was seen with small amounts of cartilage seen in the periphery. Symptoms of mass effect which resolved following surgery were noted. We believe that this previously unrecognized soft-tissue appendicular neoplasm lies at the end of a spectrum of post-traumatic ossifying lesions which includes soft-tissue chondromas and osteochondromas, as well as myositis ossificans.

Evaluation of unstable shoulders by computed tomography A preliminary study

Three patients who had various types of glenohumeral joint instability, and in whom computed tomography (CT) was utilized as an additional diagnostic modality, are presented. In two of the three patients, routine radiography supplemented with special views docu mented the presence of a Hill-Sachs lesion; in the third, an equivocal abnormality was apparent. In all three individuals, CT verified the presence of a Hill- Sachs lesion; in one patient, there was also a Bankart deformity. CT represents a new and important modal ity that may be applied to the diagnostic evaluation of patients with unstable shoulders.