Evaluation of the early phase of Bell’s palsy using 3 T MRI

Abstract

This prospective study on Bell's palsy investigated the value of 3 T MRI as a diagnostic tool to evaluate pathophysiological changes (i.e. edema) of facial nerve segments and the possibility to differentiate patients with high risk for incomplete recovery from patients who recover completely within 3 days after symptoms onset. For this institutional review board approved investigation, thirty patients (14 male, 16 female, mean age 44 years) with Bell's palsy underwent pre and postcontrast 3 T MRI of the cerebellopontine angle. T1-weighted imaging was performed (TR 20.0 ms, TE 2.46 ms, isotropic voxel size: 0.6 mm). Region-of-interest measurements were performed on the healthy and paralyzed side. To obtain normalized values, signal intensity increase percentage (SIIP) values were divided by contralateral results of the healthy side. Signal intensity measurements of examined nerve segments were compared using Wilcoxon and Mann-Whitney U tests and correlated to clinical findings categorized by the House-Brackmann score. The lesion side showed significantly higher signal intensities in the premeatal segment before and after contrast agent administration (P < 0.001). SIIP was highest in the premeatal segment compared to the geniculate ganglion (P < 0.001). Correlation analyses revealed no association between signal intensity measurements, clinical findings or early recovery rates after 3 months (P > 0.05). According to our results, early palsy-associated pathophysiological changes in the facial nerve premeatal segment might also be related to accumulation of proteins and not exclusively to edema. However, contrast agent enhancement quantification was not suitable as a diagnostic tool to distinguish different prognostic groups.

Prediction of nonrecovery in Bell's palsy using sunnybrook grading

“…As a result, factors that can predict prognosis have been sought in studies based on clinical evaluation of acute symptoms and signs, concurrent medical diseases, age, and radiological investigations. However, these predictive factors are not powerful enough in the clinical situation, and additional clinical prognostic tools are therefore needed 6–8…”

The Effect of Prednisolone on Sequelae in Bell's Palsy

“…An inflammatory process with edema of the facial nerve is supported by the findings of facial nerve enhancement on magnetic resonance imaging and swelling of the nerve during decompression surgery. [1][2][3] One theory is that a reactivation of latent herpes simplex virus may cause the nerve injury. 4,5 The prognosis in Bell's palsy is on the whole favorable, and about 70% recover completely within 6 months without treatment.…”

Evaluation of the facial nerve and internal auditory canal cross-sectional areas on three-dimensional fast imaging employing steady-state acquisition magnetic resonance imaging in Bell’s palsy

“…Several studies investigated the potential of MRI in patients with BP. Most of these studies focused on the enhancement of the FN and made attempts to answer the question of whether or not contrast enhancement of the FN is associated with the disease severity and/or prognosis in BP (3,16,17). Nevertheless, the geniculate ganglion, tympanic, or mastoid segment of the FN may be enhanced in up to 76% of patients without BP due to the rich arteriovenous plexus along the nerve.…”