Meninges: benign postoperative enhancement on MR images.

In a group of 20 postcraniotomy patients who underwent magnetic resonance imaging performed with gadopentetate dimeglumine, 16 (80%) had nonneoplastic meningeal enhancement. This was seen as either enhancement of a local dural membrane or generalized meningeal enhancement. In a control group of 23 patients, only three (13%) had similar findings. The authors believe that postcraniotomy meningeal enhancement is most likely the result of a local inflammatory process or a diffuse chemical arachnoiditis caused by bleeding into the subarachnoid space at the time of surgery. The finding does not necessarily indicate leptomeningeal tumor spread or infection.