Anatomical Study of Anterior Inferior Cerebellar Artery and Its Reciprocal Relationship with Posterior Inferior Cerebellar Artery Based on Angiographic Data.

Background: Anterior inferior cerebellar artery (AICA) can present with a myriad of variations. However, the previous studies of AICA anatomy were based on small-scale cadaveric investigation. In this study, we performed an angiographic study of AICA in 500 Chinese with Han nationality based on digital subtraction angiography (DSA).

Methods: Patients admitted to our institution between 2015 and 2018 who had underwent DSA were potential candidates for this retrospective evaluation. The exclusion criteria were: a) patients with vascular diseases of the posterior circulation; b) ischemic diseases or moyamoya disease of the anterior circulation.

Results: Five hundred patients were identified. The patients ranged in age from 6 to 75 years. Two hundred thirty-seven (62.9%, 237 of 377) patients had bilateral AICAs at the same level, and 140 (37.1%, 140 of 377) had bilateral AICAs at different levels. The developing states of AICA were grade 0 in 31 (3.5%, 31 of 896), grade 1 in 373 (41.6%, 373 of 896), grade 2 in 313 (34.9%, 313 of 896), and grade 3 in 179 (20.0%, 179 of 896) hemispheres. Two hundred twenty-one (22.1%, 221 of 1000) presented with AICA-PICA common trunks. Thirty-one (3.1%, 31 of 1000) hemispheres showed no obvious AICA angiographically. AICA arose as a single trunk in 865 (86.5%, 865 of 1000) hemispheres, and as duplicate trunks in 104 (10.4%, 10 of 1000) hemispheres. Triplicate or more trunks were not seen. AICA originating from the basilar artery fenestration accounted for 4% (20 of 500) of the cases.

Conclusions: This is the first attempt using DSA data to perform a large-scale investigation of AICA variations. The ever-growing need of endovascular intervention calls for more suitable anatomical explanation of the vascular structures.