Synovial sarcoma: dynamic contrast-enhanced MR imaging features

Objective. To determine whether previously described so-called malignant dy namic contrast-enhanced magnetic resonance (MR) imaging features - early st art, peripheral enhancement and early plateau or washout phase - occur cons istently in synovial sarcoma. Design and patients. Dynamic contrast-enhanced MR images of 10 patients wit h histologically proven synovial sarcoma were reviewed. The start, pattern and progression of tumor enhancement were assessed and correlated with hist opathology. Results. In all patients, the time interval between arterial and early tumo r enhancement was less than 7 s (mean 4.40 s, SD 2.09 s). Six synovial sarc omas showed enhancement with a subsequent rapidly progressive linear increa se in signal intensity followed by a plateau in one lesion and washout in f ive. Four lesions showed a late sustained increase in enhancement after the initial rapid increase in enhancement. The pattern of initial enhancement was peripheral in only two lesions, diffuse in four and heterogeneous in fo ur lesions. Conclusions. Enhancement of tumor within 7 s after arterial enhancement is, of the three parameters described previously, the only sign that occurs co nsistently in synovial sarcoma.