Ultrasound of the normal vagus nerve cross-sectional area in the carotid sheath

Abstract

The aim of this article is to utilize ultrasound to evaluate the normal cross-sectional area (CSA)of the vagus nerve (VN) in the carotid sheath. This study included 86 VNs in 43 healthy subjects (15 men, 28 women); mean age 42.1 years and mean body mass index 26.2 kg/m2. For each subject, the bilateral VNs were identified by US at the anterolateral neck within the common carotid sheaths. One radiologist obtained 3 separate CSA measurements for each of the bilateral VNs with complete transducer removal between each measurement. Additionally, for each participant, demographic information of age and gender as well as body mass index, weight, and height were documented. The mean CSA of the right VN in the carotid sheath was 2.1 and 1.9 mm2 for the left VN. The right VN CSA was significantly larger than the left VN (P < .012). No statistically significant correlation was noted in relation to height, weight, and age. We believe that the reference values for the normal CSA of the VN obtained in our study, could help in the sonographic evaluation of VN enlargement, as it relates to the diagnosis of various diseases affecting the VN.

The vagus nerve cross-sectional area on ultrasound in patients with type 2 diabetes

“…In accordance with our results, several prior studies also did not report any relation between VN CSA and the demographic data of healthy subjects. [ 15 , 17 , 19 , 28 ] In patients with diabetes mellitus, VN CSA was also not correlated with patients’ demographic or clinical data in in a previous study. [ 15 ] Furthermore, peripheral nerve CSA was negatively correlated with age but not with other demographic parameters [ 27 ] or with patients’ clinical data.…”

“…In prior studies using normal subjects, the CSA of the VN has also been reported to be smaller on the left side. [ 17 – 19 ] The VN is the longest cranial nerve which arises from the brainstem, exiting the medulla below the ninth cranial nerve, and extending through the jugular foramen. [ 20 ] The VN contributes to the parasympathetic control of the cervical and thoraco-abdominal structures.…”