The purpose of this prospective study was to define the enhancement pa
ttern of the facial nerve in idiopathic facial paralysis (Bell's palsy
) on magnetic resonance (MR) imaging with routine doses of gadolinium-
DTPA (0.1 mmol/kg). Using 0.5T imager, 24 patients with examined with
a mean interval time of 13.7 days between the onset of symptoms and th
e MR examination. Contralateral asymptomatic facial nerves constituted
the control group and five of the normal facial nerves (20.8 %) showe
d enhancement confined to the geniculate ganglion. Hence, contrast enh
ancement limited to the geniculate ganglion in the abnormal facial ner
ve (3 of 24) was referred to as equivocal. Not encountered in any of t
he normal facial nerves, enhancement of other segments alone or associ
ated with geniculate ganglion enhancement was considered to be abnorma
l and noted in 70.8 % of the symptomatic facial nerves. The most frequ
ently enhancing segments were the geniculate ganglion and the distal i
ntracanalicular segment.