MRI OF THE BRAIN-STEM USING FLUID ATTENUATED INVERSION RECIVERY PULSESEQUENCES

Heavily T2-weighted fluid-attenuated inversion recovery (FLAIR) sequen ces with inversion times of 2000-2500 ms and echo times of 130-200 ms were used to image the brain stem of a normal adult and five patients. These sequences produce high signal from many white matter tracts and display high lesion contrast. The corticospinal and parietopontine tr acts, lateral and medial lemnisci, superior and inferior cerebellar pe duncles, medial longitudinal fasciculi, thalamo-olivary tracts and the cuneate and gracile fasciculi gave high signal and were directly visu alised. The oculomotor and trigeminal nerves were demonstrated within the brain stem. Lesions not seen with conventional T2-weighted spin ec ho sequences were seen with high contrast in patients with infarction, multiple sclerosis, sarcoidosis, shunt obstruction and metastatic tum our. The anatomical detail and high lesion contrast given by the FLAIR pulse sequence appear likely to be of value in diagnosis of disease i n the brain stem.