Figure 5.

Pictorial diagram provides the definitions of different categories of brain tissue under ischemic insults and the lower (irreversible injury) and upper (reversible injury) MR derived oxygen metabolic index threshold values to separate core (infarct probability (IP) = 100%) from penumbra and penumbra from oligemia (IP = 0%), respectively. In addition, penumbra is further separated into non-reperfused (IP = 100%) and reperfused penumbra (IP = 0%), respectively. (Reprinted with permission from An et al.¹⁰⁵).