Bell’s Palsy Diagnosis Improved with Dynamic Contrast-Enhanced MRI

Dynamic contrast-enhanced (DCE) MRI can pick up facial nerve abnormalities that are often seen in patients who have Bell’s palsy, according to a new study.

In a study published in the Nov. 2 Clinical Radiology, investigators from Shanghai Ninth People’s Hospital in China determined that DCE-MRI could more accurately image facial nerve segments than conventional MRI.

Bell’s palsy can occur at any age, typically manifesting anywhere between ages 10-to-45. The impacted facial nerves in these individuals are frequently swollen or inflamed, leading to weakness and partial paralysis in the face muscles of these patients. In the past, researchers have tested several different sequences to see if they can accurately pinpoint Bell’s palsy hallmark facial features. But, it can be difficult, the team said.

“On the one hand, some segments of the facial nerve are too small to be assessed on conventional MRI,” said lead study author Y. Wang, a radiologist with Shanghai Ninth People’s Hospital. “On the other hand, a normal facial nerve has a certain probability of presenting enhancement on conventional MRI.”

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To determine whether DCE-MRI could be successful, Wang’s team retrospectively analyzed 13 patients between ages 7 and 69 who had surgically confirmed Bell’s palsy, using a T1-weighted volumetric interpolated breath-hold examination (VIBE) sequence. Exams were conducted between January 2015 to July 2019.

Based on their analysis, they found DCE-MRI performed better than conventional MRI in imaging facial nerve segments that are impacted by Bell’s palsy – 92.3 percent versus 38.5 percent, respectively.

The VIBE sequence also offered better contrast, higher signal-to-noise ratios, and shorter 10-second exam times, the team said. Still, the team cautioned that providers consider DCE-MRI to be a support tool to morphological imaging. It should not be viewed as a replacement.

"This approach has advantages both for the patient, in terms of safety, and for the physician, in terms of the accuracy of the diagnosis," they said. "Conventional MRI combined with DCE-MRI is a useful way to diagnose the involved segments of the affected facial nerves accurately with a shorter acquisition time compared to conventional MRI.”