Abstract
Background : The clinical significance of cerebral microlesions of less than 3 mm in diameter observed on magnetic resonance imaging (MRI) remains unclear.
Patients : In total, 390 cases with localized lesions in the lacuna of less than 15 mm in diameter were studied.
Method : Microlesions with clear margins that were less than 3 mm in diameter were categorized as low, iso or high intensity separately on each T1-weighted image (T1WI), T2-weighted image (T2WI), protonweighted image or fluid attenuated inversion recovery (FLAIR) image. The correlation between microlesions and vascular risk factors was analyzed by logistic regression analysis and the influence of microlesions on brain infarction was investigated using Cox's proportional hazards model.
Results : Microlesions were frequently observed in the anterior perforated substance, basal ganglia, and subcortical white matter. Microlesions of the basal ganglia were correlated to age and hypertension, and those of the subcortical white matter were correlated to systolic blood pressure and fasting blood sugar. Microlesions of the basal ganglia or subcortical white matter displaying a low intensity on T1WI and a high intensity on T2WI were particulary associated with risk factors. Microlesions of the anterior perforated substance did not correlate strongly with any of the risk factors. Twenty-nine of the 390 cases suffered from brain infarction during the follow-up period. Patients with multiple microlesions of the upper basal ganglia showing a low intensity on T1WI, high intensity on T2WI, and low intensity on proton or FLAIR images, more frequently developed brain infarction.
Conclusion : The clinical significance of microlesions of the anterior perforated substance is low, but microlesions of the upper basal ganglia appear to be a predictive factor of brain infarction.
