18F-flortaucipir PET imaging: Biodistribution in the Japanese population and diagnostic accuracy by Japanese readers.

Regional differences in 18F-flutemetamol accumulation between amyloid-positive and -negative brains using high-resolution dedicated head PET scanner.

High-resolution dhPET revealed significantly higher SUVRs in Aβ⁺ compared with Aβ⁻ subjects in supratentorial structures, including cerebral white matter, and in cerebellar gray matter.

[18F]-florzolotau PET imaging in Alzheimer's disease: Current evidence and future directions

Tau positron emission tomography (PET) has become a central imaging modality for in vivo detection and quantification of tau pathology across the Alzheimer's disease (AD) clinical and biological continuum. [18F]-Florzolotau is a second-generation tau PET tracer developed to improve target-to-background contrast and mitigate off-target binding relative to first-generation ligands, thereby improving interpretability for translational research and clinical use. In this narrative review, we provide a critical appraisal of the available literature on [18F]-Florzolotau PET imaging in AD, with emphasis on diagnostic and differential-diagnostic performance, the spatiotemporal topography of tau deposition in relation to Braak staging and disease progression, and the clinical significance of tracer uptake with respect to cognitive measures, disease severity, and prognosis. Eligible studies were clinical investigations published between 2020 and 2025 that applied [18F]-Florzolotau PET in cohorts spanning cognitively unimpaired individuals through symptomatic AD stages. Across reports, [18F]-Florzolotau PET differentiated AD dementia from cognitively unimpaired comparators with high accuracy, with sensitivities ≥ 90% and specificities of 87–96%. Regional uptake patterns were broadly consistent with Braak-like propagation, progressing from medial temporal regions toward associative neocortex in parallel with increasing clinical severity. Quantitative tracer uptake also correlated with global cognition and key domains, including episodic memory and executive function. We conclude that [18F]-Florzolotau PET provides a robust in vivo measure of AD tau burden, motivating further evaluation for diagnostic and prognostic applications. Larger multicenter studies with harmonized acquisition/quantification and head-to-head comparisons versus other second-generation tracers remain priorities.

Concordance Between [18F]Flortaucipir PET Visual Reads and CenTauR-Based Quantification.

Tau PET imaging with [18F]flortaucipir allows for the visualization and mapping of aggregated tau deposits, a key neuropathologic feature of Alzheimer disease (AD). A visual interpretation method for [18F]flortaucipir was approved by the Food and Drug Administration and European Medicines Agency and has been implemented for a standardized, clinically usable definition of tau PET positivity. The CenTauRz method, on the other hand, offers the possibility to harmonize the definition of tau PET positivity across different radiotracers using quantitative metrics, but its concordance with clinically relevant [18F]flortaucipir visual reads remains unclear. Methods: A convenience sample of 3991 participants, including cognitively unimpaired (CU) and cognitively impaired (CI) individuals (i.e., those with mild cognitive impairment or AD dementia), underwent [18F]flortaucipir PET imaging. Each [18F]flortaucipir scan was assessed by 3 trained readers using the approved visual interpretation method and quantified using the CenTauRz quantification pipeline in different regions of interest (ROIs). Concordance between positive visual reads and CenTauRz-defined positivity (i.e., >2 on the CenTauRz scale) was assessed using Cohen κ. Receiver-operating-characteristic (ROC) analysis evaluated the discriminative power of continuous CenTauRz values in distinguishing between negative and positive visual reads. Generalized additive models examined clinical progression on the basis of visual and CenTauRz-based assessments of tau PET positivity. Results: Concordance between visual reads and CenTauRz-based assessments of tau PET positivity was moderate, particularly in CU individuals (κ = 0.23-0.55 for CU participants, κ = 0.57-0.82 for CI participants, depending on the ROI). ROC analysis revealed that the agreement remained moderate, independent of the CenTauRz cut point used (area under the ROC curve, 0.72-0.87 vs. 0.87-0.97 for CU and CI individuals, respectively). Among discordant cases, participants with visually positive/CenTauRz-negative tau PET scans were more frequently amyloid-positive and exhibited faster clinical progression compared with visually negative/CenTauRz-positive individuals. Conclusion: Our findings highlight the relatively limited agreement between the visual assessment of [18F]flortaucipir PET images and CenTauRz-based quantification, particularly in CU individuals. Participants with visually positive/CenTauRz-negative tau PET scans showed a high frequency of amyloid positivity and faster clinical progression, suggesting that visual reads are more sensitive to heterogeneous, clinically relevant tau accumulation patterns not captured by ROI-based methods. These findings underscore the need for new quantification approaches to better capture the complex patterns of tau deposition, important for early AD detection and monitoring.

Integrated 18F-NOTA-FAPI-04 PET/MRI for quantitative assessment of disease activity in thyroid-associated ophthalmopathy.

Amyloid-β PET Radioligands in Alzheimer's Disease: From Plaque Detection to Biomarker-Guided Patient Stratification and Therapeutic Monitoring.

[18F]FDG PET outperforms MRI for detecting early tau-related neurodegeneration.