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Published on: September 25, 2019
Diagnosis of DWI-negative acute ischemic stroke: A meta-analysis
Brian L Edlow1, Shelley Hurwitz2, Jonathan A Edlow2
1From 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. bedlow@mgh.harvard.edu.
Objective:
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.
Methods:
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.
Results:
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, p < 0.001).
Conclusions:
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.
