Cerebral microbleeds on T2*-weighted images and hemorrhagic transformation after antithrombotic therapies for ischemic stroke.

To assess the predictive value of cerebral microbleeds (CMBs) on gradient-echo T2*-weighted magnetic resonance imaging for hemorrhagic transformation (HT) after antithrombotic therapy for an acute ischemic stroke, we prospectively examined the relationship between CMBs on T2*-weighted images before the start of therapy and the appearance of HT in a series of patients treated with antithrombotic therapies. The subjects were consecutive acute ischemic stroke patients admitted to Tokai University Hospital (187 subjects, mean age±SD: 74±11 years). The prevalence of CMBs was not significantly different between the subjects with and without HT on computed tomography (CT) (19% versus 36%, P=.081). In both the subgroup of patients treated with anticoagulants and the subgroup treated with antiplatelets, the prevalence of HT was not significantly different between the subjects with and without CMBs (anticoagulants, 9% versus 21%, P=.161; antiplatelets, 0% versus 9%, P=.542). The odds ratios (ORs) of increasing the National Institutes of Health Stroke Scale score (1.14, 95% confidence interval [CI]: 1.04-1.26, P=.005) and decreasing the Alberta Stroke Program Early CT Score on diffusion-weighted images (ASPECTS-DWI) (1.32, 95% CI: 1.10-1.59, P=.003) were significantly increased for the appearance of HT, but the OR of CMBs (.35, 95% CI: .09-1.41, P=.140) was not significantly increased for the appearance of HT. In conclusion, the severity of neurological deficits and the ASPECTS-DWI are closely correlated to the development of HT related to anticoagulants/antiplatelets but not to CMBs on T2*-weighted images.