NONOSSIFYING FIBROMA - CHARACTERISTICS AT MR-IMAGING WITH PATHOLOGICAL CORRELATION

PURPOSE: To correlate the findings of nonossifying fibroma at magnetic resonance (MR) imaging with those at pathologic examination. MATERIAL S AND METHODS: In 19 patients (age range, 8-25 years; mean age, 14 yea rs) with pathologically proved nonossifying fibroma, MR images were an alyzed for signal intensity and patterns of contrast enhancement. Find ings at MR imaging and biopsy were correlated. RESULTS: On T1-weighted images, all nonossifying fibromas had low signal intensity compared w ith that of skeletal muscle. On T2-weighted images, 15 lesions (79%) w ere hypointense and four (21%) were hyperintense. On gadolinium-enhanc ed images, intense contrast enhancement was seen throughout 15 lesions (heterogeneous pattern in 12 and homogeneous in three) and in the mar gins and septa in four. Extensive hypercellular fibrous tissue and hem osiderin seen at pathologic examination were depicted with low signal intensity on T2-weighted MR images. CONCLUSION: The distinguishing fea tures of nonossifying fibroma included hypointensity and septation on T2-weighted images. Signal intensity on T1- and T2-weighted MR images and the patterns of contrast enhancement were dependent on the amounts of hypercellular fibrous tissue, hemosiderin, hemorrhage, collagen, f oamy histiocytes, and bone trabeculae.