Diffusion-weighted imaging identifies a subset of lacunar infarction associated with embolic source

Background and Purpose-Small infarcts in the territory of penetrator arteri es were described as causing a number of distinct clinical syndromes. The v ascular pathophysiology underlying such infarcts is difficult to ascertain without careful pathological study. However, the occurrence of multiple, sm all infarcts, linked closely in time but dispersed widely in the brain, rai ses the possibility of an embolic mechanism. The current study determines t he frequency and clinical characteristics of patients with well-defined lac unar syndromes and the diffusion-weighted imaging (DWI) evidence of multipl e acute lesions. Methods-Sixty-two consecutive patients who presented to the emergency room with a clinically well-defined lacunar syndrome were studied by DWI within the first 3 days of admission. Results-DWI showed multiple regions of increased signal intensity in 10 pat ients (16%). A hemispheric or brain stem Index lesion") was found in all. l esion in a penetrator territory that accounted for the clinical syndrome (" DWI-hyperintense lesions other than the index lesion ("subsidiary infarcti ons") were punctate and lay within leptomeningeal artery territories in the majority. As opposed to patients with a single lacunar infarction, patient s with a subsidiary infarction more frequently (P<0.05) harbored an identif iable cause of stroke. Conclusions-Almost 1 of every 6 patients presenting with a classic lacunar syndrome has multiple infarctions demonstrated on DWI, This DWT finding usu ally indicates an identifiable cause of stroke and therefore may influence clinical decisions regarding the extent of etiologic investigations and tre atment for secondary prevention.