Clinical Study Reveals Tau PET Scans' Potential in Alzheimer's Detection

A recent study conducted by a team of researchers from the University of Gothenburg, Sweden, has unveiled significant insights regarding the efficacy of tau PET brain scans in identifying the risk of clinical progression of Alzheimer’s disease (AD). Published on June 16, 2025, in the Journal of the American Medical Association (JAMA), the study highlights the potential of tau PET scans as a biomarker for both preclinical and symptomatic stages of AD.

The research involved a comprehensive analysis of imaging data from 6,514 participants across 13 countries, aiming to assess the frequency of tau PET positivity and its correlation with clinical progression. According to lead author Dr. Alexis Moscoso, a researcher in the Department of Psychiatry and Neurochemistry at the University of Gothenburg, the findings suggest a notable rate of positive tau PET scans among cognitively unimpaired individuals. "A positive tau PET scan occurred at a nonnegligible rate among cognitively unimpaired individuals, and the combination of amyloid PET positivity and tau PET positivity was associated with a high risk of clinical progression in both preclinical and symptomatic stages of AD," Dr. Moscoso stated.

Tau protein neurofibrillary tangles and beta-amyloid plaque deposits are two pathological hallmarks of Alzheimer’s disease. While amyloid PET scans have previously been utilized to assess these pathologies, the implications of positive amyloid PET scans during the early stages of the disease remain ambiguous. The authors pointed out that amyloid positivity can appear in older individuals who do not exhibit symptoms of dementia.

In this study, the researchers utilized flortaucipir (Tauvid), the only FDA and EMA-approved biomarker for neurofibrillary tangles. The analysis revealed that out of 3,487 cognitively unimpaired participants, 349 (9.8%) were found to be tau PET positive. The frequency of tau PET positivity increased from less than 1% in individuals younger than 50 to 19% in those aged 90 and above. Furthermore, the study indicated that most tau PET-positive individuals (92%) were also amyloid PET-positive.

The study's findings are particularly striking for cognitively unimpaired participants who tested positive for both tau and amyloid PET scans, as they exhibited a 57% risk of progressing to mild cognitive impairment (MCI) or dementia within five years. In contrast, participants who were positive for only one of the PET scans or negative for both demonstrated significantly lower risks of progression (17% and 6%, respectively). Among participants with MCI at the time of the tau PET scan, those with a positive tau and amyloid profile showed a 70% absolute risk of progressing to dementia within five years.

The implications of this research extend beyond clinical diagnostics. According to Dr. Moscoso, the study contributes to a deeper understanding of tau PET’s potential utility in clinical settings, marking a significant advancement in Alzheimer’s research. The findings suggest that tau PET positivity is not only detectable in a small proportion of individuals during preclinical stages of AD but also increases in frequency as the disease progresses.

In a broader context, the study underscores the importance of early detection and intervention in Alzheimer's disease management. As the global population ages, the incidence of AD is expected to rise, necessitating advancements in diagnostic technologies and treatment strategies. This study represents a critical step towards enhancing the understanding of Alzheimer's disease pathology and the development of targeted therapeutic approaches.

As the field of Alzheimer's research continues to evolve, the integration of tau PET scans into clinical practice may offer new avenues for monitoring disease progression and developing personalized treatment plans. Future research is likely to focus on validating these findings in diverse populations and exploring the potential of tau PET as a routine diagnostic tool in the fight against Alzheimer's disease.