头颈联合64排螺旋CT血管成像诊断椎-基底动脉成窗变异

目的分析椎-基底动脉及其分支成窗变异的CT血管成像(CTA)表现,提高对该血管变异的认识。方法回顾性分析86例经头颈联合64排CTA诊断为椎-基底动脉及其分支成窗病人的影像学资料,分析椎-基底动脉及分支成窗的出现部位、形态、与周围血管及骨质的关系等特征及其合并症。结果 2051例行头颈联合64排CTA检查的病人中发现椎动脉、基底动脉或其分支成窗变异占4.2%(86例病人的88支血管),其中基底动脉为2.34%(48例),椎动脉1.8%(37例),大脑后动脉3例,小脑上动脉1例。48例基底动脉成窗中,31例位于基底动脉干,16例位于基底动脉起始部。37例椎动脉成窗中,颅内型19例,颅外型16例,颅内-外型2例。15个成窗的"窗"径小于2mm,呈孔状;73个"窗"径较大者中,37个成窗的分支粗细不等,呈"OK"手势征;36个病变分支粗细基本一致,呈部分重复走行。1例伴基底动脉成窗近端动脉瘤,3例伴其他血管的动脉瘤。2例伴大脑前动脉成窗;5例伴左侧椎动脉起源异常。结论头颈联合64排CTA能快速、直观、准确地诊断椎-基底动脉及其分支的成窗变异及其合并症,熟悉椎-基底动脉成窗的CTA特征有助于指导临床制定合理的治疗方案,提高相应治疗中的安全性。

Fenestration of vertebro-basilar artery detected by the head and carotid angiography under 64-slice multidetector spiral CT

Objective　To analyze CT angiography features of arterial fenestrations concerning with vertebro-basilar arteries and its branches in an effort to improve our understanding of this anomaly.　Methods　 Between November 2007 and July 2009, 2051 head and carotid CT angiographies were performed in our hospital, and 4.2% (88 fenestrations) were diagnosed in 86 patients. The CTA of those 86 patients were evaluated retrospectively to determine the incidence, location and configuration of the fenestration and the relationship between the anomaly and the surrounding structures. The coexisting abnormalities were also evaluated.　Results　48 fenestrations of basilar artery (2.34%) were detected in this study. The fenestrations were at the proximal portion of basilar artery trunk in 31 cases, and at vertebrobasilar junction in 16 cases. 37 fenestrations of vertebral artery (1.8%) were detected, with 19 anomalies at the intracranial level. In which, 16 fenestrations were at the extracranial level, and 2 at the atlantoaxial level and the intracranial segment of the artery. 2 fenestrations of the posterior cerebral artery and 1 fenestration of inferior cerebellar artery were found. 15 small fenestrations (less than 2 mm) presented foramen-like shape. 37 of 73 large fenestrations simulated an "ok" hand sign, and 36 showed partial duplication type of fenestration. 1 aneurysm associated with basilar artery fenestration and 3 aneurysms near the other arteries were found. In 7 patients there were additional cerebrovascular anomalies, 2 of them were associated with anterior cerebral artery fenestrations, while other 5 coexisted with origin variation in left vertebral arteries (emanated from aortic arch).　Conclusions　64-slice CTA of the cranio-cervical arteries is a rapid, intuitive, and accurate method for demonstrating vertebrobasilar artery fenestration and its coexisting abnormalities. Diagnosis of this anatomic variation prior to surgery and intervention may be helpful for procedures choice and decreasing the risk of operation.