Fibrous dysplasia: MR imaging characteristics with radiopathologic correlation

The purpose of this study was to describe the findings of MR imaging of fibrous dysplasia and to evaluate the correlation between radiologic and pathologic findings.

MR images of 13 proven cases of fibrous dysplasia were analyzed for signal intensity, hypointense rind, internal septations, cystic changes, soft-tissue extension, and patterns of contrast enhancement.

All cases of fibrous dysplasia showed low signal intensity on T1-weighted MR images. Five cases (38%) were hypointense on T2-weighted MR images, and the other eight cases (62%) were hyperintense. Hypointense rind was seen in 10 cases (77%); internal septations were seen in three cases (23%); and cystic changes was seen in two cases (15%). Soft-tissue extension was observed in four cases (31%), including one case (8%) with a pathologic fracture. After gadolinium infusion, central contrast enhancement was noted in eight cases (73%), and peripheral rim enhancement was noted in three cases (27%). Numerous bony trabeculae, confirmed pathologically, caused a hypointense signal intensity on T2-weighted images.

Patients with fibrous dysplasia showed a correlation between radiologic and pathologic findings. Our results showed that T1-weighted images reveal fibrous dysplasia as hypointense, and T2-weighted images reveal fibrous dysplasia as either hyperintense or hypointense. Signal intensity on T1- and T2-weighted images and the degree of contrast enhancement on T1-weighted images depended on the amount and degree of bony trabeculae, cellularity, collagen, and cystic and hemorrhagic changes.