前循环急性分水岭区脑梗死的病理学与影像学特点

Pathophysiologic and Imaging Characteristics of Acute Anterior Circulation Border-zone Infarction

急性分水岭区脑梗死（Border-zone infarcts， BZI）是指发生于相邻的、较大的2条或2条以上脑动脉供血区交界处的局限性脑梗死。急性BZI约占全部急性脑梗死的10％。根据动脉分布区特点BZI可分为内侧分水岭区脑梗死（ In-teral border-zone infarcts， IBZI）与皮层分水岭区脑梗死（ Cortical border -zone infarcts， CBZI）。 BZI的发病机制目前尚不明确。现有的理论认为大脑动脉支配区远端发生低灌注易发生梗死病灶。 IBZI主要是血液动力学障碍导致，而CBZI 由栓塞及低灌注引发。明确脑梗死的发病机制对有效制定防治措施十分重要。

Border -zone infarcts （ BZI） are ischemic lesions that occur in characteristic locations at the junction between two main arterial territories .These lesions constitute approximately 10%of all brain infarcts and are well described in the literature .Their pathophysiology has not yet been fully elucidated , but a commonly accepted hypothesis holds that decreased perfusion in the distal re -gions of the vascular territories leaves them vulnerable to infarction .Two types of BZI are recognized as external （cortical） and inter-nal （subcortical）.Internal border zone infarcts （IBZI） are caused mainly by hemodynamic compromise, whereas external border zone infarcts （ EBZI） are believed to result from embolism but not always associated with hypoperfusion .It is important to understand the underlying causal mechanisms in selecting most appropriate methods for managing these infarcts .