Magnetic resonance imaging (MRI) and angiography (MRA). (a) Diffusion-weighted image (DWI) on admission showed a high intensity lesion in the watershed area of the right anterior and middle cerebral arteries. (b) Fluid attenuated inversion recovery (FLAIR) on admission showed a high intensity lesion in the same area as the DWI. In addition, there were some other high intensity lesions in the deep white matter that reflected old lacunar infarctions. (c) MRA showed the stenosis of the distal portion of the right middle cerebral artery (arrowhead). (d) On the 51st day after onset, a DWI showed that the lesion was still high. (e) FLAIR on the 51st day after onset showed some of the new lesions became very low. (f) MRA on the 51st day after onset showed stenosis of the same portion of the right middle cerebral artery (arrowhead). ((a), (b), and (c)) On admission. ((d), (e), and (f)) 51 days after onset.