MR of enchondroma and chondrosarcoma: rings and arcs of Gd-DTPA enhancement.

MR studies of five chondrosarcomas and three enchondromas were performed with intravenous Gd-DTPA administration. All tumors showed enhancement of scalloped margins and curvilinear septa (ring-and-arc pattern) on T1-weighted SE sequences with Gd-DTPA. On radiologic-pathologic correlation, the enhanced areas corresponded to fibrovascular bundles surrounding hyaline cartilage lobules. The rings and arcs of enhancement with Gd-DTPA on MR is a reflection of the lobulated growth pattern of cartilaginous tumors and therefore helpful in differential diagnosis of bone tumors.