Dataset Information

Dynamic PET Measures of Tau Accumulation in Cognitively Normal Older Adults and Alzheimer's Disease Patients Measured Using [18F] THK-5351.

ABSTRACT: [18F]THK5351, a recently-developed positron emission tomography (PET) tracer for measuring tau neurofibrillary tangle accumulation, may help researchers examine aging, disease, and tau pathology in living human brains. We examined THK5351 tracer pharmacokinetics to define an optimal acquisition time for static late images.Primary measurements were calculation of regional values of distribution volume ratios (DVR) and standardized uptake value ratios (SUVR) in 6 healthy older control and 10 Alzheimer's disease (AD) participants. We examined associations between DVR and SUVR, searching for a 20 min SUVR time window that was stable and comparable to DVR. We additionally examined diagnostic group differences in this 20 min SUVR.In healthy controls, [18F]THK5351 uptake was low, with increased temporal relative to frontal binding. In AD, regional uptake was substantially higher than in healthy controls, with temporal exceeding frontal binding. Retention in cerebellar gray matter, which was used as the reference region, was low compared to other regions. Both DVR and SUVR values showed minimal change over time after 40 min. SUVR 20-40, 30-50, and 40-60 min were most consistently correlated with DVR; SUVR 40-60 min, the most stable time window, was used in further analyses. Significant (AD > healthy control) group differences existed in temporoparietal regions, with marginal medial temporal differences. We found high basal ganglia SUVR 40-60 min signal, with no group differences.We examined THK5351, a new PET tracer for measuring tau accumulation, and compared multiple analysis methods for quantifying regional tracer uptake. SUVR 40-60 min performed optimally when examining 20 min SUVR windows, and appears to be a practical method for quantifying relative regional tracer retention. The results of this study offer clinical potential, given the usefulness of THK5351-PET as a biomarker of tau pathology in aging and disease.

SUBMITTER: Lockhart SN

PROVIDER: S-EPMC4927104 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

Dynamic PET Measures of Tau Accumulation in Cognitively Normal Older Adults and Alzheimer's Disease Patients Measured Using [18F] THK-5351.

Lockhart Samuel N SN Baker Suzanne L SL Okamura Nobuyuki N Furukawa Katsutoshi K Ishiki Aiko A Furumoto Shozo S Tashiro Manabu M Yanai Kazuhiko K Arai Hiroyuki H Kudo Yukitsuka Y Harada Ryuichi R Tomita Naoki N Hiraoka Kotaro K Watanuki Shoichi S Jagust William J WJ

PloS one 20160629 6

<h4>Background</h4>[18F]THK5351, a recently-developed positron emission tomography (PET) tracer for measuring tau neurofibrillary tangle accumulation, may help researchers examine aging, disease, and tau pathology in living human brains. We examined THK5351 tracer pharmacokinetics to define an optimal acquisition time for static late images.<h4>Methods</h4>Primary measurements were calculation of regional values of distribution volume ratios (DVR) and standardized uptake value ratios (SUVR) in 6 ...[more]

PMID: 27355840

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Project description:Background: Brain 18F-AV-45 amyloid positron emission tomography (PET) in Taiwanese patients with familial Alzheimer's disease with the amyloid precursor protein (APP) p.D678H mutation tends to involve occipital and cerebellar cortical areas. However, tau pathology in patients with this specific Taiwan mutation remains unknown. In this study, we aimed to study the Tau PET images in these patients. Methods: Clinical features, brain magnetic resonance imaging/computed tomography (MRI/CT), and brain 18F-THK-5351 PET were recorded in five patients with the APP p.D678H mutation and correlated with brain 18F-AV-45 PET images. We also compared the tau deposition patterns among five patients with familial mild cognitive impairment (fMCI), six patients with sporadic amnestic mild cognitive impairment (sMCI), nine patients with mild to moderate dementia due to Alzheimer's disease (AD), and 12 healthy controls (HCs). All of the subjects also received brain 18F-AV-45 PET. Results: The nine patients with sAD and six patients with sMCI had a positive brain AV-45 PET scans, while the 12 HCs had negative brain AV-45 PET scans. All five patients with fMCI received a tau PET scan with the age at onset ranging from 46 to 53 years, in whom increased standard uptake value ratio (SUVR) of 18F-THK-5351 was noted in all seven brain cortical areas compared with the HCs. In addition, the SUVRs of 18F-THK-5351 were increased in the frontal, medial parietal, lateral parietal, lateral temporal, and occipital areas (P < 0.001) in the patients with sAD compared with the HCs. The patients with fMCI had a significant higher SUVR of 18F-THK-5351 in the cerebellar cortex compared to the patients with sMCI. The correlations between regional SUVR and Mini-Mental State Examination score and between regional SUVR and clinical dementia rating (sum box) scores within volumes of interest of Braak stage were statistically significant. Conclusion: Tau deposition was increased in the patients with fMCI compared to the HCs. Increased regional SUVR in the cerebellar cortical area was a characteristic finding in the patients with fMCI. As compared between amyloid and tau PET, the amyloid deposition is diffuse, but tau deposition is limited to the temporal lobe in the patients with fMCI.

Project description:BackgroundSemantic variant primary progressive aphasia (svPPA) is a subtype of primary progressive aphasia characterized by two-way anomia and disturbance in word comprehension, with focal atrophy in the left temporal lobe. [18F]THK-5351 was originally developed to trace tau protein. However, it has recently been suggested that [18F]THK-5351 binds to monoamine oxidase B in astrocytes, which reflects gliosis. Herein, the authors present two cases involving patients with early-stage svPPA who underwent [18F]THK-5351 positron emission tomography (PET) imaging, and examined whether [18F]THK-5351 PET imaging is more sensitive to neurodegenerative lesions than conventional imaging modalities such as magnetic resonance imaging (MRI) and cerebral blood flow (CBF)-single photon emission computed tomography (SPECT).Case presentationTwo patients, 64- and 79-year-old men, without notable medical or family history, exhibited disturbances in word comprehension and mild anomia with fluent speech and spared repetition. In both cases, surface dyslexia was observed but prosopagnosia was absent. Although mild depression was detected in 1 of the 2 patients, no behavioral disorders were present in either case. In both cases, MRI revealed atrophy in the anterior and inferior portions of the left temporal lobe. Technetium-99-ethyl cysteinate dimer ([99mTc]ECD) SPECT revealed hypoperfusion in the left temporal lobe. Alzheimer's disease was ruled out by [11C]Pittsburgh Compound-B (PiB) PET scan. Both patients fulfilled the diagnostic criteria for svPPA. Because of mild language deficits and lack of right temporal atrophy, they were considered to be at an early stage of the disease. In both cases, [18F]THK-5351 retention was observed in bilateral temporal lobes, predominantly on the left side. Comparison of different imaging modalities suggested that [18F]THK-5351 was more sensitive in detecting neurodegenerative change in the right temporal lobe than MRI and [99mTc]ECD SPECT.Conclusions[18F]THK-5351 retention was clearly demonstrated at an early stage of svPPA. Results of the present study suggest that [18F]THK-5351 PET imaging may facilitate very early diagnosis of the disease.

Dataset Information

Dynamic PET Measures of Tau Accumulation in Cognitively Normal Older Adults and Alzheimer's Disease Patients Measured Using [18F] THK-5351.

Publications

Dynamic PET Measures of Tau Accumulation in Cognitively Normal Older Adults and Alzheimer's Disease Patients Measured Using [18F] THK-5351.

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