Neoplastic vs inflammatory meningeal enhancement with Gd-DTPA.

We studied 40 consecutive patients clinically suspected of having meningeal disease, in whom both Gd-diethylenetriamine pentaacetic acid (DTPA)-enhanced magnetic resonance (MR) examinations and CSF or surgical pathologic samples were obtained. The MR examinations were retrospectively reviewed for the presence of abnormal meningeal enhancement, as well as pattern and site of enhancement. The MR findings correctly correlated with pathology results in 15 of 19 patients with suspected tumor involvement (including one true negative) and in 18 of 21 patients with suspected inflammatory meningeal conditions (including 2 true negatives). Pial enhancement was demonstrated in 62% (10 of 16) of patients with meningitis and in 29% (4 of 14) of patients with meningeal neoplastic involvement. A diffuse meningeal distribution was commonly present with inflammatory conditions (69%, 11 of 16). A nodular appearance was seen in two patients with tumor involvement of the meninges as well as in a single case of sarcoidosis but was not seen with infectious meningitis. Our data suggest that Gd-DTPA-enhanced MR imaging is sensitive to the presence of meningeal pathology but is nonspecific as to disease entity. Recognition of certain MR patterns in conjunction with clinical presentation may improve diagnosis and management of patients with suspected meningeal disease.