Hirokazu Mizutani

Peritumoral edema in osteoid osteoma on magnetic resonance imaging

Abstract Objective.To determine whether there is a relationship between the peritumoral edema caused by osteoid osteoma seen on magnetic resonance (MR) imaging and the patient’s age, duration of symptoms, or location of the lesion. Design and patients. All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, duration of symptoms, and available radiological and MR imaging examinations were included in this study. The extent of the edema in the bone marrow and extraosseous soft tissue around the nidus of osteoid osteoma on T2-weighted MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two masked observers. The relationships between the patient’s age, duration of symptoms, and location of lesions were evaluated by Pearson’s correlation coefficient and analysis of variance. Results.Twenty-seven cases met the inclusion criteria. The observer agreement on grading was good. Patients of 15 years of age or younger had significantly higher grades than patients older than 15 years. There was a moderate negative linear correlation between the patient’s age and peritumoral edema. No significant relationship was identified between edema and the duration of symptoms or the location of lesions. Conclusion. Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema.

Calcific tendinitis of the gluteus maximus tendon with cortical bone erosion : CT findings

A case of calcific tendinitis of the gluteus maximus tendon with cortical erosion is presented. Roentgenography demonstrated calcification on the posterior surface of the proximal femur. Computed tomography showed flame-like appearance of calcific tendinitis and bone erosion. Magnetic resonance imaging showed minimal inflammatory reaction around the lesion.

Reactive heterotopic ossification: Its patterns on MRI

The purpose of this report is to analyze common features of reactive heterotopic ossification, zone phenomenon and involution. Eleven cases evaluated with plain radiography and MRI were classified based on the location: intramuscular, periosteal, and intermediate (mainly the insertion site of muscles). Zone phenomenon tends to be complete in the intramuscular type and incomplete in the periosteal type. Involution is also more evident in the intramuscular type.

Magnetic resonance imaging of pseudomalignant osseous tumor of the hand.

Noninfectious, nonneoplastic reactive processes of the hand, such as myositis ossificans circumscripta, pseudomalignant osseous tumor of soft tissue, and florid reactive periostitis, appear similar radiologically and histologically and are often difficult to differentiate. Magnetic resonance (MR) findings in two such lesions are reported. The extensive reactive change in the extraosseous soft tissue and the bone marrow and the relatively small extent of ossification may be characteristic. Although low-grade infection and small osseous neoplasms with reactive changes, such as osteoid osteoma, may still remain possible causes, MR imaging provides essential evidence for including noninfective, nonneoplastic reactive processes of uncertain cause in the list of differential diagnoses.

Amyloid arthropathy of the hip joint: MR demonstration of presumed amyloid lesions in 152 patients with long-term hemodialysis.

Abstract. The aim of this study was to determine the spectrum of MR findings of presumed amyloid arthropathy of the hip joints in patients on long-term hemodialysis. We prospectively performed T1- and T2-weighted spin-echo imaging on 152 consecutive patients on hemodialysis. The duration of hemodialysis ranged from 5 months to 24 years, 2 months (mean: 8 years, 8 months). The frequency, location, and signal intensity of bone lesions were assessed. In 12 cases with contrast-enhanced MR examination, enhancement pattern of bone lesions, synovial lesions, and intra-articular lesions were characterized. Bone lesions presumed to be amyloid deposits were identified in 60 patients (39 %). Magnetic resonance imaging revealed that amyloid lesions were more extensive than anticipated by plain radiographs. All bone lesions showed decreased signal intensity on T1-weighted images. On T2-weighted images, bone lesions showed increased signal intensity in 32 patients (54 %), decreased signal intensity in 11 patients (18 %), and both increased and decreased signal intensity in 17 patients (28 %). Following intravenous injection of gadolinium-based contrast, all bone lesions showed moderate enhancement. Synovial thickening could not be identified on T1- and T2-weighted images. However, contrast-enhanced images showed thickened synovial membrane, which could be differentiated from joint fluid. Intra-articular nodules showed decreased or intermediate signal intensity on T1-weighted images and decreased signal intensity on T2-weighted images; the intra-articular nodules were contiguous with subchondral bone lesions. Magnetic resonance imaging is useful for evaluating the distribution and extent of amyloidosis of the hip joints in patients undergoing long-term hemodialysis.

Marchiafava-Bignami disease: CT and MR findings

We describe characteristic findings in a patient with Marchiafava-Bignami disease who was serially imaged with CT and MR. Involvement of the entire corpus callosum was visualized with both types of imaging. Following administration of gadolinium-DTPA, the lesion was clearly enhanced in the subacute stage.

Giant cell tumor of bone in a child

Abstract Giant cell tumor (GCT) of bone was first established as a distinct clinicopathological radiographic entity in 1940 when Jaffe distinguished it from other lesions containing giant cells. GCT is rare in patients under 15 years of age. We report a case of GCT in a 10-year-old boy whose X-ray films showed osteolysis suggesting a malignant bone tumor. We believe this to be the youngest patient with giant cell bone tumor ever reported in the Japanese literature.