Pictorial review: Trigeminal nerve: anatomy and pathology.

MRI is the imaging modality of choice when trigeminal nerve pathology is suspected. Most lesions are readily recognizable if appropriate imaging sequences are performed. Routine cranial MRI sequences augmented by a three-dimensional gradient echo sequence such as FISP (fast inflow with steady-state precession) are sufficient to demonstrate most pathological processes involving the trigeminal nerve and nucleus. Intravenous gadolinium-DTPA occasionally provides additional diagnostic information. MRI is particularly useful in planning the management of those conditions where surgical or medical intervention can result in improvement or resolution of symptoms. In this review, examples of a range of pathologies involving the trigeminal nerve and nucleus are presented.