Tau PET imaging evidence in patients with cognitive impairment: preparing for clinical use
The development and validation of molecular imaging markers for the neuropathological hallmarks of neurodegenerative diseases associated with cognitive impairment is a reality since two decades. Amyloid PET tracers have been validated analytically and are currently tested for their clinical utility. More recently tracers targeting specifically tau deposits have been developed and are currently tested in large clinical studies. The availability of these markers opens the possibility for precision medicine in a field that was limited by a gold standard diagnosis occurring only postmortem. Aim of this review is to summarize the main findings obtained using tau-specific PET tracers in clinical cohorts of patients with cognitive impairment.
Methods and Results
We report the results of a systematic literature review. Various approaches for automated image assessment have been tested, while visual rating strategies have not been validated yet. In the AD spectrum an increase in cortical binding has been consistently observed, with a topography correlated with the profile of cognitive impairment and in agreement with the knowledge on tau pathology from neuropathological series. The evidence in non-AD diseases is more limited, with discordant findings in different cohorts and with different tracers.
Post-mortem validations of in vivo data in large cohorts and studies investigating the clinical added value of this biomarker in comparison with others will be required before routine clinical use of this new modality.
KeywordsTau Positron emission tomography (PET) Alzheimer’s disease (AD) Biomarker Tauopathy
This work was supported by the Swiss National Foundation with the grant SNF Grant 320030_169876, by the Velux Foundation (project no. 1123), by the Segre Foundation, and by the CoSTREAM project, funded from the European Union Horizon 2020 research and innovation programme under Grant agreement number 667375.
CN: literature search, image acquisition, and manuscript writing; IM: manuscript writing and editing, literature review, and preparation of figures; AM, HV, PA, PU, GF: manuscript writing and editing, and literature review; VG: content planning, literature review, and manuscript writing and editing.
Compliance with ethical standards
All procedures performed in studies involving human participants were in accordance with the 1964 Helsinki Declaration and its later amendments and with the ethical standards of institutional and national research authorities.
Informed consent was obtained from all individual participants included in the study.
Conflict of interest
All authors report no potential conflicts of interest.
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