Dynamic PET-Tau Quantification for Progressive Supranuclear Palsy Diagnosis

Abstract

Tauopathies are neurodegenerative diseases caused by the abnormal accumulation of tau proteins in the brain. One uncommon tauopathy is progressive supranuclear palsy (PSP), whose symptoms often overlap with other brain disorders, and its detection is only possible postmortem since there is not an available ideal biomarker. PET-tau imaging has the potential to revolutionize the early detection of this disease. PET is a nuclear imaging test which allows seeing the functionality of organs and tissues in vivo using a radiotracer that emits radiation from inside the body. A new PET tracer called 18F-PI-2620 has shown promising results concerning the detection of PSP, with high affinity to tau aggregates and low off-target binding. This project consists of designing and testing a software for the quantification of PET images of the brain with a dynamic acquisition, which show the radiotracer distribution through time. The software performs a coregistration of the images to the standard space, where the different regions of the brain can be segmented using an atlas, and provides two physiologically meaningful parameters which are the Distribution Volume Ratio (DVR) and Standardized Uptake Value Ratio (SUVR). It gives out the DVR and SUVR values for any region of interest, as well as parametric images which help visualizing the radiotracer distribution in the brain. A set of brain PET images from 13 subjects acquired using 18F-PI-2620 has been used for the development and testing of the software, divided into healthy controls, subjects with Down syndrome, some of whom have developed Alzheimer’s disease (AD), which also implies a higher amount of abnormal deposited tau proteins. The results have shown higher DVR and SUVR values for several brain regions in those subjects who have developed AD, confirming that they have a higher radiotracer uptake and a greater amount of deposited tau proteins. This proves the correct functionality of the software and its potential as a future tool for detecting tauopathies such as PSP in combination with the radiotracer.