大脑后动脉梗塞的影像学表现及发病机制探讨

Imaging of posterior cerebral artery territory infarction and study of pathogenesy

【目的】分析PCA区梗塞可能的发病机制,为临床的病因筛查提供依据。【方法】收集急性PCA供血区梗塞患者的临床和影像学资料,并进行回顾性研究。【结果】共纳入82例患者[男性57.3%,平均年龄(64±13.7)岁]。其中表浅、深部和表浅加上深部梗塞分别占25.6%、50%和24.4%。有50例梗塞仅限于PCA区,另外32例伴有其他动脉供血区梗塞。大动脉粥样硬化(LAA,43.9%)是最常见的病因,其次是心源性栓塞(CE,19.5%),小血管闭塞(18.3%),不明原因(17.1%)及其他原因(1.2%)。在LAA的36例中,15例仅有PCA本身的病变而梗塞灶近心端的其它大动脉无粥样硬化表现,在这些患者中,梗塞机制包括大动脉粥样硬化致分支阻塞(AB,8例),原位血栓形成性血管闭塞(4例)和动脉-动脉栓塞(AA,3例)。虽然一般情况下枕叶最常受累,但在PCA本身病变时丘脑腹外侧梗塞更常见。【结论】根据不同的潜在病因,PCA区梗塞的方式各不相同,PCA本身的动脉粥样硬化通过各种机制导致卒中是PCA区梗塞相对重要的原因。

【Objective】To assess the etiologies and stroke pattern of PCA territory infarction in a Chinese population.【Methods】Consecutive patients with acute PCA territory infarction who underwent magnetic resonance imaging（MRI） and magnetic resonance angiography（MRA） within 7 days after onset.【Results】A total of 82 patients（male 57.3%,mean age 64.0±13.7 years） were recruited.Superficial,deep and superficial plus deep infarcts accounted for 25.6%,50% and 24.4% of infarcts,respectively.There were 50 patients who had infarcts limited to the PCA territory,whereas 32 patients had concomitant infarcts in other territories.Large artery atherosclerosis（LAA,43.9%） was the most frequent etiology,followed by cardiogenic embolism（19.5%）,small-vessel occlusion（18.3%）,undetermined（17.1%） and other determined（1.2%）etiology.Among the 36 patients with LAA,15 had intrinsic PCA disease without atherosclerosis in the proximal vessels.In these patients,stroke mechanisms included atheromatous branch occlusion（n=8）,in situ thrombotic occlusion（n=4） and artery-to-artery embolism（n=3）.While the occipital area was the most frequently involved in general,the ventrolateral thalamic area was more frequently involved than the occipital area in patients with intrinsic PCA atherosclerotic disease.【Conclusion】The patterns of PCA territory infarction are different according to underlying etiologies.In our population,intrinsic atherosclerotic disease is a relatively important cause of PCA territory infarction that produces strokes through a variety of mechanisms.