Development and Clinical Validation of CT-Based Regional Centiloid Method for Amyloid PET

Background: We developed and validated CT-based regional Centiloid. A CT-based regional Centiloid was developed and validated in the present study. Methods: : For development ofMRI-based or CT-based regional CLs,the cohort consist of 63 subjects (20 young controls (YC) and18 old controls (OC), and 25 Alzheimer’s disease dementia (ADD)).We used direct comparison of FMM-FBB CL (dcCL) method using MRI and CT images to define a common target region and six regional VOIs including the frontal, temporal, parietal, posterior cingulate, occipital and striatal regions. Global and regional dcCL scales were compared between MRI-based and CT-based methods. For clinical validation, cohortconsisted of 2,245subjects (627 in CN, 933 in MCI, and 685 in ADD). Results: : Both MRI-based and CT-based dcCL scales showed that FMM and FBB were highly correlated with each other, globally and regionally (R 2 = 0.96~0.99). Both FMM and FBB showed that CT-based regional dcCL scales were highly correlated with MRI-based regional dcCL scales (R 2 = 0.97~0.99). Absolute differences in regional CL scales between CT-based and MRI-based methods seemed to be relatively insignificant ( p >0.05). In our clinical validation study, the G(-)R(+) and G(+)Str(+) groups predict worse neuropsychological performance than the G(-)R(-) and the G(+)Str(-) groups ( p < 0.05) respectively. Conclusions: : Our findings suggested that it is feasible to convert FMM or FBB dcSUVR values into the dcCL scales regionally without additional MRI scans, which might in turn become a more easily accessible method for researchers and be applicable to a variety of different conditions.