Scattered brain infarct pattern on diffusion-weighted magnetic resonance imaging in patients with acute ischemic stroke

Background and Purpose: Infarct patterns on brain imaging contribute to the etiologic classification of ischemic stroke. However, the association of s pecific subtypes of infarcts and etiologic mechanisms is often weak, and ac ute lesions are frequently missed on initial computed tomography (CT). Diff usion-weighted imaging (DWI) is superior in visualizing acute ischemic lesi ons as compared to CT and conventional magnetic resonance imaging (MRI). In our prospective study, we addressed the question whether a distinct patter n of infarction on DWI is associated with infarct etiology and clinical out come. Methods: Sixty-two patients with clinical signs of acute ischemic str oke and negative acute CT upon admission underwent DWI within 10 days after the ictus. Neurological status was documented using the NIH stroke scale. A scattered lesion pattern was defined by at least 2 separate hyperintense DWI lesions within the territory of one of the major cerebral arteries. Isc hemic lesions were defined as acute if the region was demarcated strongly h yperintense in all DW images, and if the apparent diffusion coefficient was below normal. Results: In 32 patients, DWI revealed a scattered lesion pat tern, while in 30 patients a single acute lesion was detected. In patients with scattered lesions, potential arterial or cardiac embolic sources were detected in 26 patients (81.3%), as compared to 5 patients 116.6%) in the g roup with single lesions (chi (2) test, p < 0.0001). The neurological statu s of patients with scattered lesions improved significantly more than among patients with single lesions (Mann-Whitney test, p < 0.0003). Conclusion: A scattered lesion pattern on DWI in patients with acute brain infarction a nd negative initial CT scan is associated with an embolic etiology and may indicate a favorable clinical outcome. Copyright (C) 2001 S.Karger AG, Base l.