We herein report the time-related dynamic changes according to the diffusion-weighted image (DWI) findings after a cerebral ischemic attack in a 63-year-old woman. At 2 weeks after undergoing a lower limb amputation due to diabetic atherosclerosis, she experienced a sudden loss of consciousness and right hemiparesis. Magnetic resonance image revealed left frontal and parietal areas with an increased signal on the DWI, and magnetic resonance angiography (MRA) showed the left middle cerebral artery to be occluded at the superior M2 branch. However, on the next day the lesion on DWI, except for the gray matter, was observed to have almost completely resolved, and MRA showed complete recanalization of the left superior M2 branch with diminished clinical symptoms. Although a few cases of reversible DWI-identified lesions have been described in the literature, the occurrence of large, reversed DWI lesions in the middle cerebral artery territory with severe apparent diffusion coefficient decreases, as seen in our case, are exceedingly rare.