Microembolic signals at 48 hours of stroke onset contribute to new ischemia within a week

Abstract

Backgrounds and Purpose: We investigated whether new ischemic lesions (NIL) on follow-up diffusion-weighted magnetic resonance imaging (DWI) are associated with microembolic signals (MES) within 24 h or at 48 h after stroke onset.

Methods: Subjects were acute ischemic stroke patients within 24 h of onset. TCD was prospectively examined twice, within 24 h and at 48 h after onset. DWI were conducted twice, on admission and at day 7. NIL was defined as the presence of hyper-intense lesions undetected on initial DWI.

Results: Subjects comprised 125 patients consecutively enrolled from November 2004 to March 2006. TCD detected MES in 49% within 24 h and 29 % at 48 h after onset. In 27 patients with small vessel disease, MES were found in 8 (30%) patients within 24 h and 5 (19%) at 48 h of stroke onset. On the other hand, in 20 patients with large vessel disease, 11 (55%) patients within 24 h and 7 (35%) at 48 h had MES. Follow-up DWI detected NIL in 28 of 125 patients (22%) and NIL was significantly more frequent in MES-positive patients (42%) than in MES-negative patients at 48 h (15%; p=0.002). MES at 48 h (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.5-10; p=0.005), atrial fibrillation (OR, 3.6; 95%CI, 1.3-11; p=0.013), and arterial lesion (OR, 4.3; 95%CI, 1.5-12; p=0.007) represented independent factors of NIL.

Conclusion: Presence of MES at 48 h, atrial fibrillation and arterial lesions are associated with recurrence of cerebral ischemia on DWI.