Acute brain MRI-DWI patterns and stroke recurrence after mild-moderate stroke

Brain ischemic lesions identified by diffusion-weighted imaging (DWI) have been shown to predict high risk of early future ischemic events in patients with transient ischemic attacks and minor stroke. The aim of this study is to analyze different brain MRI-DWI patterns in patients with mild-moderate stroke to define acute patterns related with a higher risk of stroke recurrence in long-term follow-up (from 6 to 36 months). Retrospective review of case series from a prospective stroke record including 253 patients with mild-moderate stroke (NIHSS from 1 to 7) and acute MRI-DWI lesions. MRI-DWI lesions were analyzed to determine clinically relevant lesions, based on the number, location, age and affected arterial territories. We defined three patterns: (1) multiple versus single lesions; (2) single deep versus single cortical lesions; and (3) single lesions versus multiple lesions affecting different arterial territories and/or of different age. The impact of these patterns on recurrence was analyzed by Cox regression analysis. 38 patients (15.0%) suffered a recurrence. Univariate analysis showed the risk of recurrence for each pattern. Pattern 1: patients with multiple lesions had greater risk of recurrence than those with single lesions (28.2 vs. 9.9%; OR: 3.75 (95% CI: 1.76-7.27), p < 0.0001). Pattern 2: patients with single cortical lesions had higher risk than those with deep lesions (14.3 vs. 6.7% OR: 2.33 (95% CI: 0.86-6.33), p < 0.089). Pattern 3: patients with multiple DWI in different territories or different age had the highest recurrence rate (30.6%), OR: 4.01 (95% CI: 1.70-9.47), p < 0.001, compared to patients with single lesions. Cox regression analysis adjusted by possible confounders, showed that for pattern 1 the OR for recurrence was 2.49 (95% CI: 1.27-4.89), p = 0.008; for pattern 2, OR:1.99 (95% CI: 0.74-5.37), p = 0.17; for pattern 3, OR: 2.85 (95% CI: 1.31-6.15), p = 0.008. Brain MRI-DWI patterns assessed in the acute phase of mild-moderate stroke are useful to identify those patients at high risk of recurrence.