有孔型椎基底动脉的MR血管成像诊断

Fenestration of vertebrobasilar artery detected by MR angiography

目的 描述有孔型椎基底动脉的MR血管成像 (MRA)表现 ,以提高对该血管异常的认识。方法 回顾分析 178例头颈部增强磁共振血管造影 (CEMRA)中 10例诊断为有孔型椎基底动脉病例 ,其中 7例行颅脑CEMRA ,3例行颈部CEMRA ,钆喷替酸葡甲胺 (Gd DTPA) 0 2mmol/kg高压注射 ,小剂量团注测试延迟时间 ,增强前后行连续动态扫描。原始和减影图像经SGI 0 2工作站后处理 ,经容积重建 (实时三维 ,RT3D)、最大信号强度投影 (MIP)、薄层最大信号强度投影多平面或曲面重建血管图像 (TSMIP) ,比较各组图像对血管异常的显示情况。 5例患者同时行三维时间飞跃法 (3DTOF)MRA ,3例经DSA证实。结果 有孔型基底动脉 7例 (检出率 3 9% ,7/ 178)全部位于基底动脉下 1/ 2段 ,4例位于基底动脉干 ,3例位于椎基底动脉吻合部 ;3例有孔型椎动脉 (检出率 1 7% ,3/ 178)中 2例位于左侧V4段 ,1例位于右V3段。 4例有孔型异常 2支血管间形成小圆孔状充盈缺损 ,6例呈部分重复形。 4例有孔型血管异常合并其他血管异常 ,2例有孔型基底动脉合并脑动静脉畸形 ;2例有孔型椎动脉合并对侧永存三叉动脉 ,其中 1例还合并同侧远端椎动脉瘤 ,另 1例有孔型椎动脉同时伴有颈、基底动脉粥样硬化。RT3D能显示血管立体空间和毗邻关系 。

Objective To describe the magnetic resonance angiography (MRA) features of vertebrobasilar artery fenestration and to evaluate the utility of MRA in the diagnosis of this anomaly.Methods Between April 2002 and April 2003,178 head and carotid three dimensional contrast enhanced MR angiographies were performed in our institution,most of the patients examined had or were suspected of having cerebrovascular disease.A 1.5-T scanner was used in all studies,after determination of the individual circulation time,CE MRA was performed during power injection of 20～30 ml of Gd-DTPA.Source images were processed using a workstation SGI-02,and image post-processing software was 3D Virtuoso,31VA.The reconstructed images were then processed into volume rending and maximal intensity projection (MIP) including region of interesting and thin slice multiplane reconstruction.These 178 angiograms were retrospectively reviewed.Results 10 fenestrations of vertebrobasilar artery were detected by CE MRA.Fenestration’s limb,length,anastomosis,and relationship between the anomaly and surrounding structures were clearly and surely displayed.The fenestrations were in the proximal portion of basilar artery trunk in 4 cases,3 fenestrations were present at vertebrobasilar junction,the other 3 fenestrations located in the vertebral artery,2 in left V4 and 1 in right V3.3 anomalies of basilar artery and all cases of vertebral artery showed true duplication type of fenestration,and the other 4 basilar fenestrations were minor,with their limb length less than 3 mm.In 4 patients there were additional cerebrovascular anomalies.Two of them were associated with cerebral true AVMs,the other 2 coexisted with persistent trigeminal artery,and a saccular aneurysm at the distal end of right vertebral artery was also found.Conclusion CE MRA can provide high quality angiograms of cerebral arterial system and is suitable for the detection of vertebrobasilar artery fenestration.