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 were obtained in eight enchondromas, 11 osteochondromas, and 18 chondrosarcomas. 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 types of time-signal intensity curves. Findings were correlated with the surgical specimen in 27 cases, curettage material in three cases, and biopsy combined 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 malignant tumors. Early enhancement was seen in chondrosarcoma, not seen in enchondroma, and seen in osteochondroma only when growth plates were unfused. The sensitivity was 89%, specificity 84%, positive predictive value 84%, and negative predictive value 89%. Differentiation of malignancy from benignity on the basis of early and exponential enhancement was possible with a sensitivity of 61%, specificity 95%, positive predictive value 92%, and negative predictive value 72%. CONCLUSION: Preliminary results show that in the adult population fast contrast-enhanced MR imaging may assist in differentiation between benign and malignant cartilaginous tumors.