中文摘要：

目的 探讨小脑后下动脉（posterior inferior cerebellar artery,PICA）解剖变异致双侧小脑梗死的临床特征及发病机制.方法 对2例经颅脑MRI确诊的双侧小脑梗死患者采用CT血管造影（CTA）、磁共振血管成像（MRA）或数字减影血管造影（DSA）显示其头颈部血管,从而了解后循环血管的形态特征并复习相关文献.结果 病例1经DSA证实左侧椎动脉较细,远端管腔闭塞,通过右椎动脉代偿供血原左侧PICA供血区但欠充分,双侧PICA共同起源于右侧椎动脉.病例2经CTA证实右侧椎动脉较左侧明显细且远端显示欠清,MRA示双侧PICA共同起源于左侧椎动脉.结论 2例双侧小脑梗死患者均存在一侧椎动脉优势供血,且双侧PICA共同起源于该侧椎动脉.在该解剖变异基础上一侧椎动脉发生病变时可出现双侧小脑梗死.因此,在临床中出现双侧小脑梗死时临床医师不能忽略这一解剖变异基础.

英文摘要：

Objective To investigate the clinical features and pathogenesis of bilateral cerebellar infarction caused by anatomic variations of the posterior inferior cerebellar artery（PICA）.Methods Two patients diagnosed accurately with bilateral cerebellar infarction through cranial MRI were examined with 3-dimensional CT angiography（CTA）,magnetic resonance angiography（MRA） or digital subtraction angiography（DSA）,which clearly manifested their head and neck vascular distribution and made researchers know about the morphological features of posterior circulation blood vessel,and reviewed related literature.Results The DSA findings of the first patient demonstrated that the left vertebral artery was narrower than the right and the distal end of his left vertebral artery was occlusion.The right vertebral artery vicariously and inadequately supplied blood to the territory of the left vertebral artery.In addition,it was detected that his bilateral PICAs originated from the right vertebral artery.The CTA from the second patient showed that the right vertebral artery was narrower than the left and the distal end was not clearly displayed.Analogous to the case 1,the MRA also manifested that bilateral PICAs originated from the left vertebral artery.Conclusion Lateral vertebral artery dominance was detected in two patients with bilateral cerebellar infarction and bilateral PICAs originated from the superior vertebral artery.On the basis of anatomic variation of PICA,occlusion or stenosis in lateral vertebral artery could be the reason which brought about bilateral cerebellar infarction.Consequently,it should not be neglected that the anatomic variation happened in patients with bilateral cerebellar infarction in clinical practice.