Pathologic findings of silent, small hyperintense foci in the basal ganglia and thalamus on MRI

We analyzed the pathologic features of silent, small hyperintense foci in the basal ganglia and thalamus on MRI T2-weighted images (T2WI). Eight foci were histologically lacunar infarcts (LI), and 21 were dilated perivascular spaces (DPS). The foci with smooth margins were mostly DPS, whereas those with irregular margins were mostly LI (p = 0.018). Most putaminal foci were DPS, whereas most thalamic foci were LI (p = 0.001). The mean areas of LI and DPS overlapped below 19.6 mm2. The shape and site of hyperintense foci on T2WI are important for differentiating LI from DPS.