SEX DIFFERENCES IN THE RELATIONSHIP BETWEEN CORTICAL NEURODEGENERATION AND FDG-PET HYPOMETABOLISM IN AD AND PROGRESSIVE-MCI

ICCs for GM volumes were 0.82 with FreeSurfer and 0.88 with SPM12. Median ICCs for regional cortical thickness were 0.70 with FreeSurfer and 0.77 with SPM12+DiReCt. Median ICCs were larger for SPM-based than FreeSurfer-based MRI measures. TIVs and GM volumes were mostly larger for Siemens scans using FreeSurfer but regional biases varied with SPM12. Conclusions: ICCs between measurements from the GE vs. Siemens scans were highly comparable for most regional PET measures, and relatively less comparable for most regional MRI (volume and thickness) measures. These values suggest it is reasonable to directly compare regional PET measurements across differing MRI scanners, but most MRI measurements would require regression-based corrections. Hippocampal volumes were a notable exception with relatively strong correlations (ICC>0.95 for both sides, both pipelines) and may be directly comparable across differing MRI scanners.