Double echo steady-state free precession technique in MR neurography to evaluate extracranial facial nerve involvement in a case of Bell's palsy.

Bell's palsy is the most common cause of facial weakness involving the facial nerve. While brain MRI is often acquired to evaluate for pathology along the intracranial course of the facial nerve, evaluation of inflammation affecting the extracranial segments of the facial nerve, particularly the intraparotid segments, is uncommon. We present a case report of acute Bell's palsy in a 35-year-old pregnant patient at 38 weeks' gestation. A double-echo steady state MR neurography technique, MENSA (Multi-Echo iN Steady-state Acquisition), acquired with a conformable prototype neck coil, was utilized to visualize abnormal enlargement and signal hyperintensity of the left intraparotid facial nerve. The case highlights a presentation of Bell's palsy affecting the extracranial segments of the facial nerve. This technique may be useful for longitudinal monitoring of Bell's palsy, planning of targeted treatments, and for evaluating other pathologies affecting the facial nerve.