MRI assessment of anterior inferior cerebellar artery loop at the cerebellopontine angle in vertigo patients at a tertiary care center: a retrospective cross-sectional study

Background: Anterior inferior cerebellar artery (AICA) loops have been linked with otologic symptoms, but there is limited data on the relationship of AICA loops with vertigo. The objective of this study is to evaluate AICA loops at the cerebellopontine angle (CPA) using magnetic resonance imaging (MRI) in patients with vertigo. Methods: This retrospective study included patients who underwent MRI of the head using three-dimensional-Fast Imaging Employing Steady-state Acquisition/Constructive Interference in Steady State imaging of the CPA for the assessment of vertigo in the Department of Radiology between December 1, 2023 and March 1, 2024, excluding patients with infection, neoplasm, or previous surgery around the CPA. Two radiologists independently reviewed the magnetic resonance images. Reviewers recorded the presence or absence of an AICA loop, its classification based on the Chavda system, and its side. Results: The study included 100 patients with vertigo (57 females, 43 males; mean age, 47.94 ± 16.75 years [SD], [range, 18–80 years]). The reviewers reported that 45 of these patients (percentage, 45%; 95% confidence interval, 35.25%–54.75%) (14 males, 31 females; mean age, 47.96 ± 16.3 years [range, 18–80 years]) had AICA loop(s). Among the 200 sides examined in 100 patients, 138 (69%) had no vascular loop, 30 (15%) had Type I AICA loop, 27 (13.5%) had Type II AICA loop, and 5 (2.5%) had Type III AICA loop. There was no significant difference in the occurrence of vertigo among the various types of AICA loops on either the right side ( P = 0.293) or the left side ( P = 0.271). Conclusion: In our study, the prevalence of the AICA loop at the IAC or CPA in patients with vertigo was 45%, which is similar to studies performed in asymptomatic patients.