Edlow Brian L, Hurwitz Shelley, Edlow Jonathan A
From the Department of Neurology (B.L.E.) and Athinoula A. Martinos Center for Biomedical Imaging (B.L.E.), Massachusetts General Hospital, Department of Medicine (S.H.), Brigham and Women's Hospital, and Department of Emergency Medicine (J.A.E.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
Neurology. 2017 Jul 18;89(3):256-262. doi: 10.1212/WNL.0000000000004120. Epub 2017 Jun 14.
To determine the prevalence of diffusion-weighted imaging (DWI)-negative acute ischemic stroke (AIS) and to identify clinical characteristics of patients with DWI-negative AIS.
We systematically searched PubMed and Ovid/MEDLINE for relevant studies between 1992, the year that the DWI sequence entered clinical practice, and 2016. Studies were included based upon enrollment of consecutive patients presenting with a clinical diagnosis of AIS prior to imaging. Meta-analysis was performed to synthesize study-level data, estimate DWI-negative stroke prevalence, and estimate the odds ratios (ORs) for clinical characteristics associated with DWI-negative stroke.
Twelve articles including 3,236 AIS patients were included. The meta-analytic synthesis yielded a pooled prevalence of DWI-negative AIS of 6.8%, 95% confidence interval (CI) 4.9-9.3. In the 5 studies that reported proportion data for DWI-negative and DWI-positive AIS based on the ischemic vascular territory (n = 1,023 AIS patients), DWI-negative stroke was strongly associated with posterior circulation ischemia, as determined by clinical diagnosis at hospital discharge or repeat imaging (OR 5.1, 95% CI 2.3-11.6, < 0.001).
A small but significant percentage of patients with AIS have a negative DWI scan. Patients with neurologic deficits consistent with posterior circulation ischemia have 5 times the odds of having a negative DWI scan compared to patients with anterior circulation ischemia. AIS remains a clinical diagnosis and urgent reperfusion therapy should be considered even when an initial DWI scan is negative.
确定扩散加权成像（DWI）阴性的急性缺血性卒中（AIS）的患病率，并识别DWI阴性AIS患者的临床特征。
我们系统检索了PubMed和Ovid/MEDLINE，以查找1992年（DWI序列进入临床应用的年份）至2016年期间的相关研究。纳入的研究基于连续纳入的在成像检查前临床诊断为AIS的患者。进行荟萃分析以综合研究水平的数据，估计DWI阴性卒中的患病率，并估计与DWI阴性卒中相关的临床特征的优势比（OR）。
纳入了12篇文章，共3236例AIS患者。荟萃分析得出DWI阴性AIS的合并患病率为6.8%，95%置信区间（CI）为4.9 - 9.3。在5项根据缺血血管区域报告DWI阴性和DWI阳性AIS比例数据的研究中（n = 1023例AIS患者），根据出院时的临床诊断或重复成像确定，DWI阴性卒中与后循环缺血密切相关（OR 5.1，95% CI 2.3 - 11.6，P < 0.001）。
一小部分但比例显著的AIS患者DWI扫描呈阴性。与前循环缺血患者相比，具有与后循环缺血一致的神经功能缺损的患者DWI扫描呈阴性的几率是前者的5倍。AIS仍然是一种临床诊断，即使初始DWI扫描为阴性，也应考虑紧急再灌注治疗。
