The first 5 minutes of F18-Florbetapir scans as an estimate of regional cerebral blood flow and comparison to F18-FDG

247 Objectives Neuroimaging assessment of amyloid plaque and of non-specific neurodegeneration (e.g., FDG) may be complementary in the evaluation of neurodegenerative disorders. We explored whether scanning in the first 5 min after Florbetapir injection could be used as a surrogate marker of regional cerebral blood flow (rCBF) and assessed the degree to which these images concurred with FDG images of cerebral glucose metabolism (rCGM). Methods Florbetapir and FDG images from ADNI2 were analyzed for 70 subjects (6 Alzheimer’s Disease, 15 Mild Cognitive Impairment, 31 subjective memory complaints and 18 cognitively normal). Subjects had a dynamic florbetapir PET acquisition from 0-20 min after injection and on a separate day underwent an FDG scan starting 30 min after injection. Integrated images of the first 5 min of scanning were created for Florbetapir using a trapezoidal method. After normalization to MNI space, whole-brain normalized rCBF values were calculated for Florbetapir area under the curve (AUC) and rCGM FDG images. Correlation analysis was performed between FDG and florbetapir data from neocortical ROIs and on a voxel-wise basis. Also, Neurostat was employed to compare rCBF Florbetapir images and FDG images to a normal FDG database. Results For ROI analyses, the average correlation r value was 0.91 with an average slope of 0.81. For voxel-wise correlations, the average r value was 0.84 and the average slope was 0.78. Visual inspection of the “rCBF”/rCGM image pairs revealed substantial concordance among areas of both normal and reduced neuronal metabolism. Neurostat database comparisons also revealed substantial agreement between rCBF and rCGM image pairs. Conclusions ROI, voxel-wise and Neurostat database comparisons between 0-5 min florbetapir data and 30 min FDG images showed high mean correlations. Early florbetapir scans may be a reasonable surrogate for the functional information seen in an FDG scan. Research Support Research Supported by Avid Radiopharmacueticals, Inc.