Relationship between Vestibulocochlear Symptoms and Types of the Anterior Inferior Cerebellar Artery (AICA) Pathway in Cerebellopontine Angle

Objectives: Aims of this study are 1) to evaluate radiological characteristics of the anterior inferior cerebellar artery (AICA) using three-dimensional Fourier Transformation Constructive Interference in Steady State (3D-FT CISS) MR imaging, and 2) to investigate the relationship between types of AICA and auditory or vestibular symptom. Materials and Methods: This is a retrospective study. Forty-five adult patients, who presented with auditory symptom and/ or vestibular symptom of unknown etiology at an ENT hospital from April 2010 to August 2011, were studied. Using 3D- FT CISS images, AICA course was identified in all the patients (90 ears). The relationship was investigated between types of the AICA loop and vestibulocochlear symptom. Results: According to Chavda’s classification, 55 type I loops, 24 type II loops and11 type III loops of the AICA were observed. Only type III loops show a statistically significant association with ipsilateral hearing loss and tinnitus (p=0.0001). According to Shelton’s classification, 14 class A courses, 52 class B, 18 class C and 6 class D were observed. However, any sigificant relationship was not found between co- chleovestublar symptoms and AICA types of class A through D. Conclusion: A significant relationship was found between AICA loop and auditory symptom, when it extends more than 50% of the length of IAC. In these patients, neurovascular compression of vestibulocochlear nerve could be considered as a possible cause of hearing deterioration and tinnitus. (J Clinical Otolaryngol 2012;23:74–78)