Cartilaginous tumors: Fast contrast-enhanced MR imaging

PURPOSE: To differentiate between benign and malignant cartilaginous tumors with fast contrast material-enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: In 37 patients, fast contrast-enhanced MR images wer e obtained in eight enchondromas, 11 osteochondromas, and 18 chondrosarcoma s. Start of enhancement-early, within 10 seconds after arterial enhancement ; delayed, between 10 seconds and 2 minutes; late, after 5 minutes on spin- echo images-and progression of enhancement were represented with three type s of time-signal intensity curves. Findings were correlated with the surgic al specimen in 27 cases, curettage material in three cases, and biopsy comb ined with long-term follow-up findings in seven cases. RESULTS: Start of enhancement and the combination of start and progression of enhancement correlated significantly (P < .001) with benign and malignan t tumors. Early enhancement was seen in chondrosarcoma, not seen in enchond roma, and seen in osteochondroma only when growth plates were unfused. The sensitivity was 89%, specificity 84%, positive predictive value 84%, and ne gative predictive value 89% Differentiation of malignancy from benignity on the basis of early and exponential enhancement was possible with a sensiti vity of 61%, specificity 95%, positive predictive value 92%, and negative p redictive value 72%. CONCLUSION: Preliminary results show that in the adult population fast cont rast-enhanced MR imaging may assist in differentiation between benign and m alignant cartilaginous tumors.