Kvistad Christopher Elnan, Logallo Nicola, Thomassen Lars, Moen Gunnar, Waje-Andreassen Ulrike, Naess Halvor
Department of Neurology, Haukeland University Hospital, University of Bergen, Bergen, Norway.
Cerebrovasc Dis. 2014;38(3):219-25. doi: 10.1159/000366264. Epub 2014 Oct 29.
MR diffusion-weighted imaging (DWI) has revolutionized neuroimaging and contributed to a tissue-based redefinition of transient ischemic attack (TIA). Stroke patients with DWI lesions may have neurological symptoms that resolve completely within 24 h, suggesting successful vessel recanalization. Prior studies of stroke patients with transient symptoms have not found any predilection for DWI lesions in any specific territory. Other studies have, however, reported an association between higher brain dysfunction and presence of DWI lesions in patients with transient ischemic symptoms, suggesting a high rate of cortical affection in these patients. We sought to see whether DWI location in stroke patients with transient symptoms <24 h differed from those with persistent symptoms ≥ 24 h. We hypothesized an association between transient symptoms <24 h and cortical DWI lesion localization due to a possible higher rate of vessel recanalization in patients with transient symptoms causing distal cortical infarctions.
Ischemic stroke patients examined with DWI and admitted within 24 h after symptom onset between February 2006 and November 2013 were prospectively registered in a database (The Bergen NORSTROKE Registry). Based on neurological examination 24 h after admission, patients were classified as having either transient symptoms <24 h (DWI <24) or persistent symptoms ≥ 24 h (DWI ≥ 24). DWI lesions were classified into different groups depending on lesion location: cortical lesions, confined to the supratentorial cortex; large subcortical lesions, located in the hemispheric white matter, basal ganglia, internal capsule, thalamus or corona radiate with a diameter ≥ 15 mm; lacunar lesions, located in the same territory as large subcortical lesions with a diameter <15 mm; mixed cortical-subcortical lesions, located in both supratentorial cortex and subcortex; cerebellar lesions, confined to the cerebellum; brain stem lesions, confined to the brain stem; multiple locations, located in more than one of the above defined areas.
A total of 142 ischemic stroke patients had DWI <24 and 830 DWI ≥ 24. Cortical DWI location was more frequent in patients with DWI <24 (54.2% vs. 29.5%, p < 0.001), while proportions of mixed cortical-subcortical lesions (13.4% vs. 26.5%, p = 0.001) and lesions with multiple locations (5.6% vs. 11.1%, p = 0.048) were less frequent as compared to DWI ≥ 24. Cortical DWI location was independently associated with DWI <24 when adjusted for confounders in multiple regression analyses (OR 1.89, 95% CI 1.28-2.81, p = 0.001).
Cortical DWI location was independently associated with transient stroke symptoms <24 h. This may be explained by vessel recanalization, resulting in upstream transportation of remaining particles and distal cortical lesions.
磁共振扩散加权成像（DWI）彻底改变了神经影像学，并有助于基于组织对短暂性脑缺血发作（TIA）进行重新定义。有DWI病变的卒中患者可能出现神经症状，且这些症状可在24小时内完全缓解，提示血管成功再通。既往针对有短暂症状的卒中患者的研究未发现DWI病变在任何特定区域有偏好性。然而，其他研究报告称，短暂性缺血症状患者中，较高的脑功能障碍与DWI病变的存在相关，这表明这些患者的皮质受累率较高。我们试图了解症状持续时间<24小时的短暂性症状卒中患者的DWI病变位置与症状持续时间≥24小时的持续性症状患者是否不同。我们推测，由于短暂性症状患者血管再通率可能较高，导致远端皮质梗死，因此症状持续时间<24小时与皮质DWI病变定位之间存在关联。
2006年2月至2013年11月期间，对症状发作后24小时内接受DWI检查并入院的缺血性卒中患者进行前瞻性登记入数据库（卑尔根NORSTROKE登记库）。根据入院后24小时的神经学检查，将患者分为症状持续时间<24小时（DWI<24）或症状持续时间≥24小时（DWI≥24）。根据病变位置，将DWI病变分为不同组：皮质病变，局限于幕上皮质；大的皮质下病变，位于半球白质、基底节、内囊、丘脑或放射冠，直径≥15毫米；腔隙性病变，位于与大的皮质下病变相同区域，直径<15毫米；皮质-皮质下混合病变，位于幕上皮质和皮质下；小脑病变，局限于小脑；脑干病变，局限于脑干；多部位病变，位于上述定义区域中的多个区域。
共有142例缺血性卒中患者DWI<24，830例DWI≥24。DWI<24的患者中皮质DWI定位更为常见（54.2%对29.5%，p<0.001），而与DWI≥24相比，皮质-皮质下混合病变（13.4%对26.5%，p=0.001）和多部位病变（5.6%对11.1%，p=0.048）的比例较低。在多元回归分析中对混杂因素进行校正后，皮质DWI定位与DWI<24独立相关（OR 1.89，95%CI 1.28-2.81，p=0.001）。
皮质DWI定位与症状持续时间<24小时的短暂性卒中症状独立相关。这可能是由于血管再通，导致剩余颗粒向上游输送并形成远端皮质病变。
