The Correlation Between Diffusion-weighted Mri And Clinical Factors In Patients With Transient Ischemic Attack: A Meta-analysis

Objective: The purpose of this study was to evaluate the correlation between appearances on diffusion-weighted MRI (DWI) and clinical factors in patients with transient ischemic attack (TIA), and to study the utility value of DWI in evaluating the early stroke risk after TIA.Method: We searched PubMed, Ovid and CNKI database etc. using index terms. Studies which reported the correlation between appearances on DWI and clinical factors in patients with TIA were systematically reviewed. Clinical and DWI data were recorded on clinical symptoms, risk factors, likely etiology, number of patients with positive DWI, delay between TIA and DWI and etc. in all the studies which met our inclusion criteria. We then performed a meta-analysis using Stata, version 10.0.Results: 1 One hundred and thirty-one potentially relevant articles were identified, of which 32 met our inclusion criteria finally. Among the 32 studies including 2791 patients, the median mean age was 67 and the median mean delay to DWI scan was 37.8 hours. The aggregate rate of DWI positivity was 34%, with frequency by site ranging from 13% to 60%.2 Odds ratios(OR) were calculated for positive versus negative DWI for each clinical feature under investigation. Because of their heterogeneity, estimates from studies of previous TIA or stroke (P = 0.003), intracranial or extracranial arteries stenosis(P = 0.009), dysphasia(P = 0.000) and symptom duration≥60 minutes(P = 0.000) were combined using the DerSimonian-Laird method. Estimates from the other studies were combined using the Mantel– Haenszel method.3 For the poor symmetry of the funnel plots and P value of Egger's Test (0.099, 0.034, 0.083, 0.039 and 0.022, respctively) , there might be publication bias in the studies of diabetes, dyslipidemia, motor deficits, dysphasia and symptom duration≥60 minutes. The fail-safe number of the studies of motor deficits (390.0), dysphasia (256.4) and symptom duration≥60 minutes (730.9) indicated that the result of this analysis was stable.4 As the result of our meta-analysis, several clinical factors were associated with positive DWI including symptom duration≥60 minutes (22 studies; OR, 2.37; 95% confidence interval (CI), 1.59 to 3.53; P=0.000), motor deficits (17studies; OR, 2.34; 95% CI, 1.88 to 2.90; P=0.000), dysphasia (15 studies; OR, 2.06; 95% CI, 1.17 to 3.63; P=0.013), dysarthria (10 studies; OR, 1.85; 95% CI, 1.28 to 2.68; P=0.001), atrial fibrillation (16 studies; OR, 2.24; 95% CI, 1.64 to 3.06; P=0.000) and large-artery atherosclerosis (LAA) (16 studies; OR, 1.92; 95%CI, 1.30 to 2.81; P=0.001). However age≥60, hypertension, diabetes, previous stroke or TIA, ischemic heart disease and dyslipidemia were not associated with positive DWI. A sensitivity analysis was also performed which confirmed the previous result.Conclusions: Presence of acute ischemic lesions on DWI correlates with symptom duration≥60 minutes,distinctive symptoms such as motor deficits, dysphasia and dysarthria as well as the presence of atrial fibrillation and LAA.