FIG 1. 83-year-old woman with aphasia and right-sided weakness imaged initially at 6 hours from stroke onset.

A–G, Images are DW (A), ADC (B), FA (C), rCBF (D), MTT (E), rCBV (F), and 6-day follow-up T2-weighted. Three regions of interest are shown on the rCBF map in D. Region 1, "infarct core" covers the area that has hyperintensity on the DW image, abnormality on rCBF and MTT images, and hyperintensity on follow-up T2-weighted image. Region 2, "penumbra that infarcts" covers the area that has no abnormality on DW image, but that is abnormal on rCBF and MTT images and has hyperintensity on follow-up T2-weighted image. Region 3, "hypoperfused tissue that remains viable," covers the area that has abnormality on rCBF and MTT images but that is normal on DW image and is normal on follow-up T2-weighted image.