Magnetic resonance imaging of the facial nerve during Bell's palsy.

Twenty-five patients with Bell's palsy were evaluated to assess the efficacy of gadolinium (Gd+)-enhanced MRI in determining: (1) the site of facial nerve enhancement, (2) the relationship between EMG findings and Gd+ MRIs, and (3) the usefulness of Gd+ MRI in predicting recovery of facial function. Eighteen of twenty-five patients had enhancement of the facial nerve during Gd+ MRI whereas seven did not. The most common areas of facial nerve enhancement were the labyrinthine, geniculate ganglion, and proximal tympanic segments of the facial nerve. EMGs were performed on ten patients who lost nerve excitability. The segments of facial nerve enhanced during Gd+ MRI varied in location and intensity in patients who maintained nerve excitability and in patients who lost nerve excitability. There was no correlation between EMG findings and location of facial nerve enhancement in patients who lost nerve excitability. The location of facial nerve enhancement during Gd+ MRI was not useful in predicting recovery of facial paralysis.