ACHE and Alzheimer disease: Furthermore, we hypothesized (2) that the inferior temporal gyrus to medial temporal (ITM) ratio of cerebral perfusion, which contrasts perfusion in areas of AD- and non-AD-degeneration,13,21 and perfusion of temporo-parietal cortices, serving as markers of AD-specific degeneration, would also be correlated with cortical AChE activity.