Purpose:To prospectively evaluate the association between clinical features and structural abnormalities found at magnetic resonance (MR) imaging in patients with osteoarthritis (OA) of the knee. Materials and Methods:The study was approved by the institutional medical ethics review board.

The presented comprehensive MR scoring system for osteoarthritic changes of the knee has a good to very good inter-observer and intra-observer reproducibility. Thus the score form with its definitions can be used for standardized assessment of osteoarthritic changes to monitor medical therapy in research studies.

Purpose: To explore the potential of perfusion-corrected diffusion-weighted magnetic resonance imaging (MRI) in characterizing soft-tissue tumors. Materials and Methods:Diffusion-weighted MRI was performed in 23 histologically proven soft-tissue masses using a diffusion-weighted spin-echo sequence with diffusion gradient strengths yielding five b-values (0 -701 seconds/ mm 2 ). True diffusion coefficients and perfusion fractions were estimated and compared with apparent diffusion coefficients (ADCs).Results: ADC values of all tumors, subcutaneous fat, and muscle were significantly higher than true diffusion coefficients, indicating a contribution of perfusion to the ADC. True diffusion coefficients of malignant tumors (1.08 ϫ 10 -3 mm 2 /second) were significantly lower than those of benign masses (1.71 ϫ 10 -3 mm 2 /second), whereas ADC values between these groups were not significantly different. Conclusion:Perfusion-corrected diffusion-weighted MRI has potential in differentiating benign from malignant softtissue masses.

Static and dynamic contrast-enhanced MR imaging, when added to nonenhanced MR imaging, improved differentiation between benign and malignant soft-tissue lesions.

The clinical and radiographic findings in 104 patients with chondroblastoma are presented. Pain was an almost constant presenting complaint, often accompanied in the case of para-articular lesions by impaired function of an adjacent joint. The majority (80%) were in long bones with a mean age of presentation of 16 years. The characteristic radiological image of these lesions was an eccentric radiolucency, having a sharply defined sclerotic margin and containing areas of calcification in approximately a third of cases. They were always related to a growth plate. Nearly half were confined to the affected epiphysis or apophysis itself, but most of the remainder had traversed the growth plate to involve also the adjacent metaphysis. The bones around the knee and the proximal ends of the humerus and femur were the sites of predilection. A minority (20%) affected flat bones and short tubular bones of the hand and foot, with a peculiar affinity for the calcaneus and talus. The mean age of presentation of these was 28 years. The radiological pattern was similar, except for a greater tendency to expand the affected bone. Complications included the formation of a secondary aneurysmal bone cyst in 16 cases (10 of them in long bones), one malignant chondroblastoma, and one fibrosarcoma developing after radiation of the original chondroblastoma.

Percutaneous thermocoagulation is a safe and effective method for treatment of osteoid osteoma at any location. Repeated thermocoagulation is successful in patients with persistent symptoms.

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Bone marrow edema-like lesions change in volume in the majority of patients with osteoarthritis; associations with clinical features Abstract It has been suggested that bone marrow edema-like (BME) lesions in the knee are associated with progression of osteoarthritis (OA). The purpose of our study in patients with OA was to evaluate prospectively changes of BME lesions over 2 years and their relationship with clinical features. Magnetic resonance (MR) images of the knee were obtained from 182 patients (20% male; aged 43-76 years; mean age 59 years) who had been diagnosed with familial symptomatic OA at multiple joint sites. MR images were made at baseline and at 2 years follow-up. BME lesions in 2 years were associated with clinical features assessed by Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores. A total of 327 BME lesions were recorded. Total size of BME lesions changed in 90 patients (66%). Size of individual lesions changed in 147 foci (45%): new lesions appeared in 69 (21%), existing lesions disappeared in 32 (10%), increased in size in 26 (8%) and decreased in size in 20 (6%) lesions. Increase or decrease of BME lesions, over a 2-year time period, was not associated with severity of WOMAC scores. BME lesions fluctuated in the majority of patients with OA over a 2-year time period. These changes were not associated with severity of WOMAC scores at the study end point.