ApoJ levels between apolipoprotein ε4 allele status. (A) Complete PiB-PET imaging subgroup, (B) HC from the PiB-PET imaging subgroup only, (C) MCI from the PiB-PET imaging subgroup only, and (D) AD from the PiB-PET imaging subgroup only. Abbreviations: APoJ, apolipoprotein J; APOE ε4, apolipoprotein ε4; SUVR, standardized uptake value ratio; AD, Alzheimer's disease; MCI, mild cognitive impairment; HC, healthy control; PiB-PET, Pittsburgh compound B-positron emission tomography.