Computer-aided diagnostic reporting of FDG PET for the diagnosis of Alzheimer's disease

Temporoparietal hypometabolism on 18F-FDG PET is one of the core biomarkers for the biomarker-based diagnosis of Alzheimer's disease. The traditional readout of 18F-FDG PET for diagnostic reports is a subjective visual rating. However, this is loaded with substantial inter-rater variability. Standardization of readouts is a key factor for the use of markers in the clinic. Automated tools have been developed aimed at aiding diagnostic reporting and making it more reliable. Some involve the statistical voxel-by-voxel comparison of 18F-FDG uptake compared to a normative dataset, which provides a statistical map of difference of metabolism and requires expert judgement. Others provide a summary metric of temporoparietal hypometabolism, where a cutoff defines normality/abnormality. Strengths, weaknesses, and cautionary warnings of visual rating and both classes of tools are reviewed and discussed. © 2013 Italian Association of Nuclear Medicine and Molecular Imaging.