Figure 1.

Representative cases of CCD.

(a) 76 year-old AD (A+T+) patient with posterior cortical atrophy syndrome. CCD is noted on ¹⁸F-FDG PET (top row), with left cerebellar hypometabolism (arrowhead). Cortical hypometabolism is asymmetric, with predominant involvement of the hemisphere contralateral to cerebellar hypometabolism (arrow). Significant asymmetry is also noted on ¹⁸F-Flortaucipir PET (dotted arrow, middle row), with greater binding in the right cerebral cortex mirroring hypometabolism, which is not the case for ¹¹C-PIB (bottom row). The right panel shows selected ¹⁸F-FDG axial slices of patients with CCD and clinical diagnoses of corticobasal syndrome (b), semantic variant primary progressive aphasia (c), and progressive supra-nuclear palsy (D, very mild CCD). Cortical and cerebellar indices of asymmetry (IA) are indicated for ¹⁸F-FDG.