MRI analysis of vestibulocochlear neurovascular compression in 28 patients with vestibular paroxysmia

Abstract

Objective To analyze the MRI characteristics of vestibulocochlea neurovascular compression in patients with vestibular paroxysmia (VP) and to investigate the effect of the compression, its site and degree, on the occurrence of VP. Methods Twenty-eight cases of VP (VP group) and 28 cases of vertiginous patients other than VP (control group) were retrospectively reviewed.Three dimensional magnetic resonance angiography (3D-MRA) was performed and the data were used for neurovascular cross-compression (NVCC) analysis.The frequency and type of NVCC, the origin of the offending vessel and the distance between compression site and brainstem were compared between the two groups. Results The frequency of NVCC was 96.4%（27/28） in VP group, with a significant difference compared with control group (13/28，46.4%；χ2=17.15，P<0.01).The most common NVCC type was vascular loop compression at vestibulocochlear nerve(15/35, 42.9%).Anterior inferior cerebellar artery was the most common offending vessel (25/35, 71.4%) in VP group.There were no significant differences between the two groups in the type of NVCC or the origin of the offending vessel.The frequency on the distortion and (or) displacement of vestibulocochlear nerve which was severely compressed by vessel in VP group (7/56, 12.5%) was significantly higher than that in control group (0; P=0.013).The distance between compression site and brainstem was (8.57±5.08) mm in VP group, and (8.93±4.64) mm in control group, showing no significant difference. The ratio that the distance was less than 15 mm between compression site and brainstem in unilateral NVCC of VP group (100%) was significantly higher than unilateral NVCC of control group (7/10, P=0.033). Conclusions The VP patients have higher NVCC incidence and the most common NVCC type is vascular loop compression at vestibulocochlear nerve which is mainly caused by anterior inferior cerebellar artery.NVCC in VP patients mostly occurs in the central myelin portion of vestibulocochlear nerve.The site and degree of neurovascular compression may relate to the occurrence of VP. Key words: Vertigo; Vestibular diseases; Vestibulocochlear nerve; Nerve compression syndromes; Vascular diseases; Magnetic resonance imaging