A, Statistical parametric maps of regional hypoperfusion in the AD group (relative to the CN group). All colored voxels are contained within clusters with a corrected cluster-level P value of .05. Yellow voxels are regions of greatest group differences. The most significant hypoperfusion is in the posterior cingulate gyri and parietal association cortices. B, Same analysis as in A, after accounting for global perfusion. C, Same analysis as in A, with data corrected for PVEs and after accounting for global perfusion. Although significance and spatial extent of hypoperfusion are reduced, the regional pattern remains very similar and suggests group effects cannot be fully explained by underlying cortical atrophy.