Evaluation of the hyperintense acute reperfusion marker for the detection of ischemia in anterior and posterior circulation in patients with transient ischemic /neurological attack

在本研究项目中，我们旨在评估高强度急性再灌注标志物（HARM）在短暂性脑缺血发作（TIA）或短暂性神经发作（TNA）患者中的发生率。最初，HARM是在急性缺血性卒中后描述的，是由急性血管闭塞再通和连续再灌注后血脑屏障受损引起的。血脑屏障的破坏导致对比剂在蛛网膜下腔的积聚，这可以在液体衰减反转恢复（FLAIR）图像上得到很好的证明。短暂性脑缺血发作被定义为一种短暂的局灶性神经功能缺损，可能由脑血管引起。与此相反，短暂性神经系统发作被定义为具有各种病因的短暂性非局灶性神经功能缺损，但也包括脑血管原因。TIA的临床诊断通常是不正确的，并且TIA和TNA的区分也很困难。MRI是诊断或排除TIA/TNA患者急性脑缺血最重要的诊断手段。在大约三分之二的TIA病例中可以检测到急性缺血性病变，而在大约五分之一的TNA病例中可以通过弥散加权成像（DWI）检测到急性缺血性病变。额外的灌注加权成像（PWI）只能略微增加这一比例。高强度急性再灌注标志物可作为DWI、PWI的补充，缩小现有诊断差距。特别是，在TNA的情况下，这可能具有重要的临床相关性，以避免不当治疗，甚至在MRI表现不佳后未经进一步诊断测试而被解雇。因此，本研究的目的是评估具有统计学意义的TIA和TNA患者中HARM的发生率，并探讨其与症状持续时间和解剖定位的关系。此外，还将详细分析HARM情况下对比剂在蛛网膜下腔的蓄积动态。

In the present research project we aim to evaluate the incidence of the hyperintense acute reperfusion marker (HARM) in patients with transient ischemic attack (TIA) or transient neurological attack (TNA). Initially, HARM was described after acute ischemic stroke and is caused by impairment of the blood-brain barrier after recanalization of an acute vessel occlusion and consecutive reperfusion. Disruption of the blood-brain barrier results in the accumulation of contrast agent in the subarachnoid space, which can be demonstrated superbly on fluid attenuated inversion recovery (FLAIR) images.Transient ischemic attacks are defined as a transient focal neurological deficit with a likely cerebrovascular cause. In contrast to this, transient neurological attacks are defined as a transient non-focal neurological deficit with various etiologies, which however also include cerebrovascular causes. The clinical diagnosis of a TIA is often incorrect and the differentiation of TIA and TNA can also be difficult. The MRI is the most important diagnostic procedure for the detection or exclusion of acute cerebral ischemia in patients with TIA/TNA. Acute ischemic lesions can be detected in approximately two thirds of all TIA cases and only in about one-fifth of TNA cases on diffusion-weighted imaging (DWI). Additional perfusion-weighted imaging (PWI) can only slightly increase this proportion. The hyperintense acute reperfusion marker could be complementary to DWI and PWI and could reduce the existing diagnostic gap. In particular, in the case of a TNA this could be of major clinical relevance, in order to avoid mistreatment or even dismissal without further diagnostic testing after unremarkable MRI.Therefore, the aim of this study is to evaluate the incidence of HARM in a statistically relevant number of patients with TIA and TNA and to investigate associations with symptom duration and anatomical localization. In addition, the dynamics of contrast agent accumulation in the subarachnoid space in the case of HARM will be analyzed in detail.