世界卒中组织主席，澳大利亚国立卒中研究协会主任，墨尔本大学神经病学教授，本届欧洲卒中大会卒中新旧定义专题讨论会主席Geoffrey A. Donnan在会上作了题为“临床定义：旧的观念”的发言，本报记者在专题会后对G.A. Donnan教授做了专访，精彩内容如下：  

《INTERNATIONAL CIRCULATION》: In 2002， the new definition of TIA was proposed as a “brief episode of neurological dysfunction caused by a focal disturbance of brain or retinal ischemia， with clinical symptoms typically lasting less than 1 hour， and without evidence of infarction.” What is the progress in the definition of TIA since 2002? Why do we stress the importance of the new definition， how is this going to influence clinical practice?
2002年曾更新了TIA的定义，即TIA为“局部脑组织或视网膜缺血，引起短暂的神经功能异常发作。典型的临床症状持续时间不超过1小时，没有临床急性脑梗死的证据”。近年来TIA的定义有哪些新的进展？我们为什么强调TIA的新定义，对临床实践的意义是什么？

Dr. G.Donnan: The new definition incorporates the idea of tissue damage in imaging， particularly MRI or CT， and it appears that the presence of damage in MRI predicts even more precisely the subsequent risk of stroke. That is over the clinical scores， such as the ABCD2 score. So ABCD2 score plus MRI might give you a better indication of what the risk actually is.This new definition might make it easier for cognition of stratified risk and predict consequences in clinical practice. High risk patients should be treated very quickly. Low risk patients will still be treated， but the urgency is less than the high risk patients.
新定义涉及在头颅影像如CT或MRI上提示有病灶。影像学上显示病灶对卒中复发具有更强的预测能力，优于临床评分，如ABCD2评分。所以，结合ABCD2评分和头颅影像学表现，能够更好地预测脑卒中复发的风险。新定义有助于我们在临床工作中对卒中进行风险分层，预测卒中结局。风险高的患者需要尽快给予治疗，风险低的患者治疗紧迫性相对较低。

《INTERNATIONAL CIRCULATION》: The long-standing definition has been based on the assumption that TIAs are associated with complete resolution of brain ischemia occurring rapidly enough to cause only transient symptoms and no permanent brain injury. In contrast， ischemic stroke was thought to cause permanent injury to brain parenchyma. The similarity of these acute clinical syndromes made it difficult to differentiate them; they were distinguished on the basis of an arbitrary criterion for the duration of symptoms. In  addition to the time criteria， what information could help clinicians make a sound diagnosis of TIA in routine clinical practice?
传统的TIA定义是基于如下假设，即TIA是能够完全缓解的脑组织短时缺血，症状仅一过性的出现，不会造成永久性脑损伤。相比之下，缺血性卒中则导致脑实质的永久性损伤。由于TIA和卒中具有诸多共性，很难将二者鉴别开来。大多数情况下是根据人为设定的症状持续时间来鉴别TIA和卒中。除了这一标准以外，您认为还有哪些信息有助于临床医生在医疗实践中正确诊断TIA？

Dr. G.Donnan: It is a very important question. I think the imaging is the additional criteria which helps stratifying the risk. We have the ABCD2 score which enables us to stratify the risk very well. But Dr. Coutts from Canada demonstrates that if you have the information from MRI， you are allowed to stratify the risk even further. The additional information about the clinical aspects such as the duration of symptoms or presence of neurological signs is implicated in ABCD2 score. The imaging appears to be very important.
这是一个非常重要的问题。我认为除了上述标准以外，影像学表现同样有助于风险分层及鉴别TIA和脑卒中。在临床上，ABCD2评分有助于风险分层。但是来自加拿大的Coutts医生指出，影像学表现有助于我们更好地进行风险分层。ABCD2评分主要包括的是一些临床信息，如症状持续时间、神经系统体征的出现等。所以，影像学表现在风险分层中显得非常重要。

《INTERNATIONAL CIRCULATION》: The introduction of new MRI techniques has greatly improved the sensitivity for detecting brain ischemia and infarction. What are your comments on the value of imaging techniques such as diffusion-weighted MRI in the diagnosis of TIA? To what extent does the diffusion-weighted MRI correlate with the brain parenchyma ischemic lesions?
新型MRI技术的出现极大提高了脑缺血和脑梗死病灶检出的敏感性。您认为，弥散加权MRI（DWI）等成像技术对TIA诊断的价值是什么？弥散加权MRI与脑实质缺血性病灶的相关性如何？

Dr. G.Donnan: DWI is incredibly important because it not only gives you information about whether there is parenchyma damage or not， but also gives you indication about what the mechanism for the ischemic stroke actually is. For example， if you have an acute TIA， and the DWI shows acute lesions in both hemispheres， it might be considered as an embolism from the heart. In broad terms， if the DWI is positive， then the parenchyma is ultimately damaged. And also the perfusion adds even more information about whether the tissue is under threat and may identify the penumbra.
DWI对于缺血性脑血管病的诊断非常重要。通过DWI，不仅可以了解脑实质是否存在病灶，还对缺血性脑血管病的发生机制有一定提示作用。例如对于TIA患者，如果DWI上显示双侧大脑半球急性缺血性病灶，则提示心源性脑栓塞。DWI与脑实质缺血性病灶之间存在相关性。从广义上来讲，如果DWI上出现病灶，则提示脑实质受损。DWI能提供更多信息，提示脑实质缺血是否有挽救机会，便于确认缺血半暗带。