APOE4 not a predictor for smaller right hippocampal radial distance in PD-MCI groupAPOE4 not a predictor for smaller right hippocampal radial distance in PD-CN when comparing to NCOnly trend-level association between APOE4 and larger bilateral temporal, occipital, and left frontal horn radial distance of the lateral ventricles in the PD-MCI group relative to PD-CN. This evidence concerns the gene APOE and Parkinson disease.