P3‐379: BRAIN DIFFUSION TENSOR IMAGING METRICS IN ISCHEMIC LESIONS IN VASCULAR COGNITIVE IMPAIRMENT

related to SUVR (p < .001). Mean SUVR was 1.56 6 1.32 for APOEε4 genotype carriers (E4+) and 1.30 60.23 for non-carriers (E4-) (p< .001). There was no significant main effect for age, gender or ethnicity on SUVR. However, the following interactions were present: (1) SUVR for E4+White non-Hispanics (WNHs) was higher than E4+ Hispanics, but E4WNHs had lower SUVR than E4Hispanics; (2) E4+ males had higher SUVR than E4+ females. The optimal SUVR threshold for amyloid positivity among all subjects (n1⁄4152), using ROC analyses and Youden’s criteria, was 1.42 (sensitivity 1⁄494%; specificity 1⁄4 92.5 %). For E4subjects this threshold was 1.33 and 1.45 for E4+ subjects. Conclusions:Amyloid load was not significantly influenced by age, gender, ethnicity and cognitive status, other than the interactions between E4 status, ethnicity and gender, but was higher among E4+ than E4subjects, as was the optimal SUVR threshold for amyloid positivity. Research studies in which quantitative thresholds for amyloid positivity are used should consider the impact of E4+ and E4status, and the resulting clinical progression rates.