NEFL and Alzheimer disease: In ROI analyses, plasma NfL changes were associated with atrophy progression in AD-vulnerable ROIs for both Aβ groups, but associations with hypometabolism progression were only significant for Aβ+ participants (gray matter volume change: Aβ− CImp, r = −0.29, P < .001; Aβ+ CU, r = −0.25, P = .01; Aβ+ CImp, r = −0.17, P = .002; FDG PET SUVR change: Aβ+ CU, r = −0.42, P = .002; and Aβ+ CImp, r = −0.30, P < .001) (eFigures 20 and 21 in Supplement 1).