Before revision:  Longitudinal positron emission tomography (PET) is used to measure the extent of tau inclusions; and PET-based image biomarkers are a promising technology for AD diagnosis and prognosis.
After revision:  Longitudinal positron emission tomography (PET) scans can be used quantify the extend of abnormal tau spread. Such PET-based image biomarkers are a promising technology for AD diagnosis and prognosis.