Mechanism in progressive lacunar infarction: a case report with magnetic resonance imaging.

BACKGROUND The mechanism of a progressive lacunar infarction is not well understood, and changes in ischemic tissue after onset have not yet been clarified clinically. OBJECTIVE To investigate the pathophysiological characteristics of a case of progressive lacunar infarction using diffusion-weighted and conventional magnetic resonance imaging (MRI) scans. PATIENT A 73-year-old woman was hospitalized 18 hours after stroke onset and was diagnosed as having a lacunar infarction in the perforating territory of the left middle cerebral artery. Despite treatment, the hemiparesis worsened, with the peak on the fourth day after onset. Diffusion-weighted and conventional MRI scans provided clues to the pathogenesis. FINDINGS AND CONCLUSIONS In the acute stage, gradual enlargement of the hyperintense lesion, reflecting fresh ischemic tissue, and neurological deterioration were observed by serial examination of diffusion-weighted MRI scans. A conventional coronal MRI scan revealed a 2-layered ischemic lesion, suggesting the involvement of perforating arteries. These findings indicated that hemodynamic impairment of the microcirculation in the perforators was the major cause of the lacunar infarction.