Tau PET in neurodegenerative diseases manifesting dementia

Noninvasive imaging of tau pathology can contribute to the early and differential diagnosis of neurodegenerative diseases and evaluating the efficacy of disease-specific therapies. For in vivo imaging of tau protein deposits in the human brain, PET tracers should exhibit high binding affinity to the ß-pleated sheet structure of PHF-tau, high binding selectivity to tau over amyloid-ß, and high blood-brain barrier permeability. Several tau PET tracers have been developed and tested in humans. Recent tau PET studies have demonstrated a high amount of tracer retention in sites that have a predilection for the cortical deposition of tau protein aggregates in patients with Alzheimer's disease (AD). The amount of tracer retention is closely associated with dementia severity and neurodegeneration. Therefore, tau PET is expected to be useful for tracking disease progression, assessing disease severity, and accurately predicting dementia prognosis. In this chapter, we will discuss recent progress in the development of tau-selective PET tracers and clinical PET studies using these tracers.