fibrous dysplasia ( RID3738 ) Polyostotic > monostotic. Radiography: Ground glass matrix but range from purely lytic to purely sclerotic. CT: Narrow zone of transition, sclerosis, cortical breakthrough. MR: T1 low to intermediate SI. T2 heterogeneous intermediate to high SI. Gd variable enhancement. Bone Scan: Mild to marked increase of uptake. DDx: ABC, lytic phase of Paget, Osteoblastoma.