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TIA是指突然发生的局灶性神经系统功能丧失,由于特定的动脉供血区内的脑血流(CBF)急剧减少,通常持续时间不超过24小时。以前认为,TIA不遗留神经功能缺损、脑组织不出现不可逆性的损害。但在近来的描述中,TIA病人在CT扫描时也可显示缺血性梗塞。推测,大多数TIA是源于栓塞,血液动力学所致的TIA少见,但确实存在。由于侧支循环的功能代偿,脑血管粥样硬化性损伤一般要有血液动力学因素改变,如原发性血压下降到危险点时才能变为严重。另一方面,一个或多个动脉狭窄,甚至完全阻塞,不说明TIA血液动力学改变。血液动力学性TIA的证据可依靠详细分析症状激发因素,也可通过脑循环的应激试验测定
TIA refers to a sudden loss of focal nervous system function that typically lasts no longer than 24 hours due to a sharp reduction in cerebral blood flow (CBF) within a given arterial blood supply area. In the past that, TIA does not leave neurological deficits, brain tissue does not appear irreversible damage. However, in the recent description, TIA patients also showed ischemic infarction on CT scans. Speculated that the majority of TIA is derived from embolism, hemodynamic TIA rare, but does exist. Due to the functional compensation of collateral circulation, cerebrovascular atherosclerotic lesions generally have hemodynamic changes, such as primary blood pressure drops to a dangerous point can become serious. On the other hand, one or more arteries stenosed, or even completely obstructed, do not account for TIA hemodynamic changes. Evidence of haemodynamic TIA may depend on a detailed analysis of the symptom-provoking factors, as well as on stress tests of the cerebral circulation