Mlynash M, Olivot J-M, Tong D C, Lansberg M G, Eyngorn I, Kemp S, Moseley M E, Albers G W
Department of Neurology and Neurological Sciences, Stanford Stroke Center, 701 Welch Road, Suite B325, Palo Alto, CA 94304, USA.
Neurology. 2009 Mar 31;72(13):1127-33. doi: 10.1212/01.wnl.0000340983.00152.69. Epub 2008 Dec 17.
Transient ischemic attacks (TIA) predict future stroke. However, there are no sensitive and specific diagnostic criteria for TIA and interobserver agreement regarding the diagnosis is poor. Diffusion-weighted MRI (DWI) demonstrates acute ischemic lesions in approximately 30% of TIA patients; the yield of perfusion-weighted MRI (PWI) is unclear.
We prospectively performed both DWI and PWI within 48 hours of symptom onset in consecutive patients admitted with suspected hemispheric TIAs of <24 hours symptom duration. Two independent raters, blinded to clinical features, assessed the presence and location of acute DWI and PWI lesions. Lesions were correlated with suspected clinical localization and baseline characteristics. Clinical features predictive of a PWI lesion were assessed.
Forty-three patients met the inclusion criteria. Thirty-three percent had a PWI lesion and 35% had a DWI lesion. Seven patients (16%) had both PWI and DWI lesions and 7 (16%) had only PWI lesions. The combined yield for identification of either a PWI or a DWI was 51%. DWI lesions occurred in the clinically suspected hemisphere in 93% of patients; PWI lesions in 86%. PWI lesions occurred more frequently when the MRI was performed within 12 hours of symptom resolution, in patients with symptoms of speech impairment, and among individuals younger than 60 years.
The combination of early diffusion-weighted MRI and perfusion-weighted MRI can document the presence of a cerebral ischemic lesion in approximately half of all patients who present with a suspected hemispheric transient ischemic attack (TIA). MRI has the potential to improve the accuracy of TIA diagnosis. ACA = anterior cerebral artery; CI = confidence interval; DWI = diffusion-weighted MRI; ICA = internal carotid artery; MCA = middle cerebral artery; MRA = magnetic resonance angiography; MTT = mean transit time; OR = odds ratios; PCA = posterior cerebral artery; PWI = perfusion-weighted MRI; RR = risk ratios; TIA = transient ischemic attacks; TOAST = Trial of Org 10172 in Acute Stroke Treatment.
短暂性脑缺血发作（TIA）可预测未来发生中风。然而，目前尚无针对TIA的敏感且特异的诊断标准，观察者间关于TIA诊断的一致性较差。弥散加权磁共振成像（DWI）在约30%的TIA患者中可显示急性缺血性病变；灌注加权磁共振成像（PWI）的检出率尚不清楚。
我们对连续收治的疑似半球性TIA且症状持续时间<24小时的患者，在症状发作后48小时内前瞻性地进行了DWI和PWI检查。两名独立的评估者在对临床特征不知情的情况下，评估急性DWI和PWI病变的存在及位置。将病变与疑似临床定位及基线特征进行关联分析。评估预测PWI病变的临床特征。
43例患者符合纳入标准。33%的患者有PWI病变，35%的患者有DWI病变。7例患者（16%）同时有PWI和DWI病变，7例（16%）仅有PWI病变。PWI或DWI病变的联合检出率为51%。93%的患者DWI病变出现在临床怀疑的半球；86%的患者PWI病变出现在该半球。当在症状缓解后12小时内进行磁共振成像检查时、有言语障碍症状的患者以及60岁以下个体中，PWI病变更常见。
早期弥散加权磁共振成像和灌注加权磁共振成像相结合，可在约一半疑似半球性短暂性脑缺血发作（TIA）的患者中证实存在脑缺血病变。磁共振成像有提高TIA诊断准确性的潜力。ACA = 大脑前动脉；CI = 置信区间；DWI = 弥散加权磁共振成像；ICA = 颈内动脉；MCA = 大脑中动脉；MRA = 磁共振血管造影；MTT = 平均通过时间；OR = 比值比；PCA = 大脑后动脉；PWI = 灌注加权磁共振成像；RR = 风险比；TIA = 短暂性脑缺血发作；TOAST = 急性卒中治疗中Org 10172的试验
