Gadolinium-enhanced MR of the postoperative internal auditory canal following acoustic neuroma resection via the middle fossa approach.

PURPOSE To evaluate the ability of gadolinium-enhanced MR in detecting recurrent tumor in patients whose acoustic neuromas were surgically removed via the middle cranial fossa approach. PATIENTS AND METHODS Postoperative gadolinium-enhanced exams of 13 of 44 patients who underwent excision of acoustic neuromas via the middle cranial fossa approach were reviewed. RESULTS Postoperative enhancement was seen in 12 of the 13 patients; two patients underwent serial exams without significant change. On the basis of a single exam, we were unable to conclusively differentiate postoperative enhancement from residual or recurrent tumor. CONCLUSIONS A single exam is of limited value. Serial studies are recommended to identify changes that would indicate tumor growth. A proposed MR follow-up schedule is an initial baseline exam within 2 months of surgery and a repeat exam during the second postoperative year.