The number, type, side, site, and size of focal lesions were recorded. Lesions equivalent to the signal characteristics of cerebrospinal fluid on T1-weighted images and measuring more than 3 mm in diameter, as well as wedge-shaped corticosubcortical lesions, were regarded as brain infarcts. We did not use computer-based volumetric analysis. For estimation of lesion volumes, we grouped the infarcts into 4 categories based on their largest diameter (3-9, 10-29, 30-59, and ≥60 mm), and the radii used for calculations were 3, 10, 20, and 30 mm, respectively. The volume of the lesion was then estimated using the formula for calculating the volume of a ball. The number and volumes of infarcts affecting different anatomic sites were evaluated on both sides and on the right and left sides separately. The sites included (1) brain lobes (corticosubcortical lesions in the frontal, temporal, parietal, and occipital lobes); (2) vascular territories (deep and superficial anterior cerebral arteries, middle cerebral artery, posterior cerebral artery, internal cerebral artery, and border-zone areas); and (3) specific locations, ie, the medulla, pons, cerebellum, optic radiation, thalamus, caudate, putamen, pallidum, genu of internal capsule, anterior and posterior capsules, anterior and posterior corona radiata, anterior and posterior centrum semiovale, genu, body and splenium of corpus callosum, angular gyrus, hypothalamus, hippocampus, and amygdala. Prefrontosubcortical circuits14 include connections among the frontal cortex, caudate, pallidum, thalamus, and thalamocortical circuit. The thalamocortical circuit includes the genu of internal capsule, anterior capsule, anterior corona radiata, and anterior centrum semiovale.