Diagnosis of variants of carotid-vertebasilar anastomoses on MR angiography / 中华放射学杂志

ABSTRACT

Objective To explore the feature of embryonic communication between the carotid and vertebro-basilar system using MRA of head and neck on MR. Methods The MRA images from 7 246 consecutive patients in Liaocheng People's hospital between June 2009 and December 2015 were retrospectively reviewed. The feature of embryonic communication between internal carotid, external carotid artery and vertebro-basilar system using MRA was analyzed by two doctors. Results Forty-four cases of embryonic communication between the carotid and vertebro-basilar system were found. Thirty-nine cases of primitive trigeminal artery (PTA) and primitive trigeminal artery variants (PTAV) were detected by MRA. The prevalence of both PTA and PTAV was 0.54% (PTA, 27 cases;PTAV, 12 cases). Twenty-three cases of PTA were lateral types;four cases were medial types. All PTA originated from C4 portion of internal carotid artery, of which 27 cases connected with the basilar artery and two cases connected with the superior cerebellar artery. The region of the BA proximal to the site of convergence with the PTA was hypoplastic in seven cases and completely absent in two cases. Three cases of primitive hypoglossal artery and 2 cases of primitive proatlantal artery were detected by MRA. The prevalence of primitive hypoglossal artery and primitive proatlantal artery was 0.04% and 0.03 % respectively. Two cases of primitive hypoglossal artery were from the lateral internal carotid artery and one was from the external carotid artery. It's all on the right side. One case of primitive proatlantal artery was on the left which arises from the external carotid artery, one on the right which originated from the outer part of the internal carotid artery. Thirty-four cases were coexisted with other variants of head and neck vessels. All of the primitive hypoglossal arteries were coexisted with vertebral artery absence. One case of primitive proatlantal intersegmental artery was coexisted with vertebral artery dysplasia. Eighteen cases were associated with cerebral infarctions, and three cases with aneurysm. Conclusions MRA can accurately assess the variants of carotid-vertebasilar anastomoses and have diagnostic significance.