Department of Otorhinolaryngology, Sanliurfa Training and Research Hospital, Şanlıurfa, Turkey.
Department of Otorhinolaryngology, Mersin City Education and Research Hospital, Mersin, Turkey.
Int J Clin Pract. 2021 May;75(5):e13971. doi: 10.1111/ijcp.13971. Epub 2021 Jan 7.
Evaluation of cranial nerve morphology through measuring cross-sectional area (CSA) on magnetic resonance imaging (MRI) is increasing day-by-day in clinical diseases. In Bell's palsy (BP), the manifestation of the enlarged CSA of the facial nerve (FN) may be used for diagnosis. This study aims to evaluate whether there is an enlargement of the cisternal FN in BP.
This retrospective study included 43 patients diagnosed with BP. In the reconstructed MRI, the long (LD) and short (SD) diameters of the paralytic and normal sides of the FNs located in the cerebellopontine angle were measured, and the CSA was calculated using the Radinsky formula. Before the radiologic measurement, a preliminary experiment was carried out on the rat sciatic nerve to be able to determine the actual nerve boundary on MRI.
There was a statistically significant relationship between paralytic and normal sides in the measurements of LD, SD, and CSA. The paralytic side was larger than the normal side in the cisternal FN. According to the Receiver Operating Characteristic (ROC) curve, BP can be estimated with 60% sensitivity and 70% specificity by the CSA of the FN more than 1.04 mm . As a result of the preliminary experiment, it was found that the actual nerve boundary was at approximately 50% intensity between the minimum and maximum values.
Although entrapment of FN in the labyrinthine segment in BP was known, this study showed that the cisternal FN, which could be evaluated more conveniently, enlarged in the paralytic side compared with the normal side, and revealed the necessity of performing the comparison amongst the MRI studies on BP patients by a standardised measurement method. This study will also help clinicians to make a decision in the diagnosis of BP by giving a cut-off value for the CSA.
通过磁共振成像（MRI）测量截面积（CSA）来评估颅神经形态在临床疾病中日渐增多。在贝尔氏面瘫（BP）中，面神经（FN）CSA 增大的表现可用于诊断。本研究旨在评估 BP 中是否存在面神经脑池段（cisternal FN）增大。
本回顾性研究纳入了 43 例确诊为 BP 的患者。在重建的 MRI 中，测量了位于桥小脑角的麻痹侧和正常侧 FN 的长（LD）和短（SD）直径，并使用 Radinsky 公式计算 CSA。在进行放射学测量之前，我们对大鼠坐骨神经进行了初步实验，以便能够在 MRI 上确定实际神经边界。
LD、SD 和 CSA 的测量值在麻痹侧和正常侧之间存在统计学显著关系。麻痹侧的 cisternal FN 大于正常侧。根据Receiver Operating Characteristic（ROC）曲线，FN CSA 大于 1.04mm 时，BP 的敏感性为 60%，特异性为 70%，可进行估计。初步实验发现，实际神经边界约为最小和最大强度值之间的 50%。
尽管已知 BP 中 FN 在迷路段受压，但本研究表明，麻痹侧的 cisternal FN 较正常侧增大，并且表明需要通过标准化测量方法对 BP 患者的 MRI 研究进行比较。本研究还将通过为 CSA 提供截断值，帮助临床医生在诊断 BP 时做出决策。
