MR imaging of trigeminal schwannomas

Five trigeminal schwannomas were studied with MR imaging to determine the diagnostic utility of this modality and the imaging appearance of these rare lesions. All lesions were detected with multiplanar T1- and T2-weighted images, including one lesion not visualized on CT. Because of its ability to localize the lesion to the preganglionic (eta = 2), gaglionic (eta = 5), and postgaglionic (eta = 3) portions of the trigeminal nerve, MR imaging was more specific than CT in three additional cases. The anatomic location, shape, and relative MR relaxation parameters of schwannomas were usually adequate to differentiate them from meningiomas, epidermoids, and cholesterol granulomas of the petrous apex. Findings on MR imaging often aided surgical planning