Figure 5. Time course of an ischemic infarction. Images demonstrate the evolution of an ischemic infarction involving the left cerebellar hemisphere and left middle cerebellar peduncle. Both transverse DW images (DWI; b = 1,000 sec/mm2; effective gradient, 14 mT/m; repetition time msec/echo time msec, 6,000/108; matrix, 256 x 128; field of view, 400 x 200 mm; section thickness, 6 mm with 1-mm gap) and transverse ADC maps are displayed. The patient underwent MR imaging 6 hours after the onset of acute neurologic symptoms. At 6 hours, the lesion (arrows) is hyperintense on the DW images and hypointense on the corresponding ADC map. The lesion becomes progressively more hyperintense on DW images, reaching its maximum hyperintensity at the 58-hour time point, when it also reaches its maximum hypointensity on ADC maps. At 7 days, there is ongoing resolution of the lesion on both DW images and ADC maps. By 134 days, there is subtle hypointensity on the DW image and hyperintensity on the ADC images.