Related Experiment Video
Updated: Jul 13, 2026
05:17
Hybrid PET/MRI Imaging of Alzheimer's Disease Based on 18F-AV-1451
Published on: April 18, 2025
A probabilistic framework for clinicopathological Alzheimer's disease using tau-PET
Bastiaan G J van Tol1,2, Colin Groot3,4, Marie R Vermeiren3,4,5
1Alzheimer Center Amsterdam, Department of Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC location VUmc, Amsterdam, The Netherlands. b.g.j.vantol@amsterdamumc.nl.
Alzheimer'S Research & Therapy
|July 11, 2026
Summary
[18F]flortaucipir tau-PET scans show high accuracy for diagnosing Alzheimer's disease (AD). Combining tau-PET with amyloid-PET further improves diagnostic probability, especially in older adults.
Area of Science:
- Neurology
- Radiology
- Nuclear Medicine
Background:
- 18F]flortaucipir tau-PET imaging detects neurofibrillary tangle (NFT) pathology, a key hallmark of Alzheimer's disease (AD).
- Current clinical interpretation of tau-PET is qualitative, lacking quantitative estimates of diagnostic probability.
- This study quantifies the diagnostic probability of AD based on tau-PET scan results, considering age and amyloid-PET status.
Purpose of the Study:
- To evaluate the positive and negative predictive values (PPV/NPV) of tau-PET for clinicopathological AD.
- To examine how patient age and amyloid-PET status influence the diagnostic probability of AD after tau-PET scans.
- To assess the utility of sequential amyloid-PET and tau-PET imaging in improving AD diagnosis.
Main Methods:
- Calculated PPV and NPV of tau-PET for clinicopathological AD (MCI or dementia with AD etiology).
- Modeled PPV/NPV using literature-derived sensitivity/specificity of [18F]flortaucipir PET for Braak V/VI NFT pathology.
- Incorporated age-dependent tau-PET positivity rates in cognitively unimpaired individuals and hypothetical pre-PET AD probabilities.
Main Results:
- Tau-PET demonstrated high PPV for clinicopathological AD, with minor age-related declines (e.g., 84% at 50-55 vs. 75% at 85-90 years, at 50% pre-PET probability).
- Tau-PET NPV was consistently high and showed negligible age-related decline (e.g., 92% at 50-55 vs. 90% at 85-90 years, at 50% pre-PET probability).
- Sequential amyloid-PET and tau-PET significantly increased PPV, particularly in older adults (e.g., 30% pre-PET probability increased from 56% to 83% in 75-80 year olds).
Conclusions:
- 18F]flortaucipir tau-PET offers high PPV and NPV for diagnosing clinicopathological AD.
- Sequential amyloid-PET and tau-PET imaging enhances the probability of AD diagnosis, especially in elderly individuals.
- The study highlights tau-PET's clinical value, emphasizing the impact of age and pre-scan diagnostic certainty on post-scan AD probabilities.
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