Figure 1b. Left-sided hemiparesis in a 45-year-old man. (a) Axial CT scan of the head obtained 6 hours after onset of symptoms. Curved arrow denotes medial demarcation of the posterior limb of the right internal capsule. Note that the lateral margin of the right internal capsule is poorly defined due to decreased attenuation in the structure that makes up the lateral border—the lentiform nucleus. Compare this to the normal left internal capsule and left lentiform nucleus (straight arrow). (b) Axial CT scan of the head obtained superior to a. There is global decrease in gray matter-white matter differentiation in the right cerebral hemisphere that corresponds to the MCA distribution. (c) Axial CT scan of the head was obtained on hospital day 3 and demonstrates an area of increased attenuation (straight arrows) that corresponds to hemorrhage into a region of infarction. The nonhemorrhagic areas of infarction are seen as hypoattenuating (curved arrow).