Sonographic evaluation of the vagus nerves: Protocol, reference values, and side‐to‐side differences

摘要

ABSTRACT Introduction Reported sonographic reference values for the vagus nerves (VNs) vary greatly. We aimed to generate reference values in a large cohort and examine intrarater, interrater, and across‐ultrasound systems agreement. Methods The VNs of 60 healthy subjects were examined by 2 sonographers and with 2 ultrasound systems. Cross‐sectional areas (CSAs) of each VN were assessed at the level of the carotid sinus [proximal measurement level (ML)] and thyroid gland (distal ML). Results Mean VN CSA was significantly larger on the right side (proximal ML: 2.7?±?0.6?mm 2 vs. 2.1?±?0.5?mm 2 ; distal ML: 2.6?±?0.6?mm 2 vs. 1.9?±?0.4?mm 2 ). VN CSA decreased with increasing age. There were good intrarater, interrater, and across‐ultrasound systems agreements. Discussion The right VN CSA is significantly larger than the left. These side‐ and age‐specific reference values for the VN may be useful for future studies. Muscle Nerve 57 : 766–771, 2018