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Developing sensitive diagnostic methods for a longitudinal evaluation of the status of liver fibrosis is a priority. This study is aimed at assessing the significance of longitudinal positron emission tomography (PET) imaging with 18F-labeling tracers for assessing liver fibrosis in a rat model with bile duct ligation (BDL). Twenty-one 6-week-old Sprague-Dawley male rats were used in this study. Longitudinal PET images using [18F]N-2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]FEPPA) (n = 3), [18F]fluoroacetate ([18F]FAc) (n = 3), and 18F-fluoro-2-deoxy-D-glucose ([18F]FDG) (n = 3) were obtained at 0, 1, and 2 weeks after BDL. Biochemical assays, histological assays, immunohistochemical staining assays, and next generation sequencing analyses were also performed at 0 (n = 3), 1 (n = 3), 2 (n = 3), and 3 (n = 3) weeks after BDL, which demonstrated the severe damage in rat livers after BDL. Regarding [18F]FEPPA and [18F]FDG, there was a significantly higher uptake in the liver after BDL (both P < 0.05), which lasted until week 2. However, the uptake of [18F]FAc in the liver was not significantly different before and after BDL (P = 0.28). Collectively, both [18F]FEPPA and [18F]FDG can serve as sensitive probes for detecting the liver fibrosis. However, [18F]FAc is not recommended to diagnose liver fibrosis. [ABSTRACT FROM AUTHOR]

Background and Objectives : Neurodegeneration and vascular burden are the two most common causes of post-stroke cognitive impairment. However, the interrelationship between the plasma beta-amyloid (Aβ) and tau protein, cortical atrophy and brain amyloid accumulation on PET imaging in stroke patients is undetermined. We aimed to explore: (1) the relationships of cortical thickness and amyloid burden on PET with plasma Aβ40, Aβ42, tau protein and their composite scores in stroke patients; and (2) the associations of post-stroke cognitive presentations with these plasma and neuroimaging biomarkers. Methods : The prospective project recruited first-ever ischemic stroke patients around 3 months after stroke onset. The plasma Aβ40, Aβ42, and total tau protein were measured with the immunomagnetic reduction method. Cortical thickness was evaluated on MRI, and cortical amyloid plaque deposition was evaluated by 18F-florbetapir PET. Cognition was evaluated with Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS), Dementia Rating Scale-2 (DRS-2). Results : The study recruited 24 stroke patients and 13 normal controls. The plasma tau and tau*Aβ42 levels were correlated with mean cortical thickness after age adjustment. The Aβ42/Aβ40 ratio was correlated with global cortical 18F-florbetapir uptake value. The DRS-2 and GDS scores were associated with mean cortical thickness and plasma biomarkers, including Aβ42/Aβ40, tau, tau*Aβ42, tau/Aβ42, and tau/Aβ40 levels, in stroke patients. Conclusion : Plasma Aβ, tau, and their composite scores were associated with cognitive performance 3 months after stroke, and these plasma biomarkers were correlated with corresponding imaging biomarkers of neurodegeneration. Further longitudinal studies with a larger sample size are warranted to replicate the study results. [ABSTRACT FROM AUTHOR]

Developing sensitive diagnostic methods for a longitudinal evaluation of the status of liver fibrosis is a priority. This study is aimed at assessing the significance of longitudinal positron emission tomography (PET) imaging with 18F-labeling tracers for assessing liver fibrosis in a rat model with bile duct ligation (BDL). Twenty-one 6-week-old Sprague-Dawley male rats were used in this study. Longitudinal PET images using [18F]N-2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]FEPPA) (n = 3), [18F]fluoroacetate ([18F]FAc) (n = 3), and 18F-fluoro-2-deoxy-D-glucose ([18F]FDG) (n = 3) were obtained at 0, 1, and 2 weeks after BDL. Biochemical assays, histological assays, immunohistochemical staining assays, and next generation sequencing analyses were also performed at 0 (n = 3), 1 (n = 3), 2 (n = 3), and 3 (n = 3) weeks after BDL, which demonstrated the severe damage in rat livers after BDL. Regarding [18F]FEPPA and [18F]FDG, there was a significantly higher uptake in the liver after BDL (both P < 0.05), which lasted until week 2. However, the uptake of [18F]FAc in the liver was not significantly different before and after BDL (P = 0.28). Collectively, both [18F]FEPPA and [18F]FDG can serve as sensitive probes for detecting the liver fibrosis. However, [18F]FAc is not recommended to diagnose liver fibrosis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The amyloid AV-45 (florbetapir) positron emission tomography (PET) has been used in the study of the familial Alzheimer's disease (FAD) with the D678H amyloid precursor protein (APP) mutation. In addition, the progress of the disease remains unknown.Objective: We aim to investigate the progression rate of amyloid accumulation in FAD patients with this mutation by neuroimages analysis.Methods: The clinical course, changes in cognitive function, brain magnetic resonance imaging (MRI) and 18F-AV-45 PET scan were investigated in FAD patients and sporadic AD (sAD) patients. We compared the amyloid deposition pattern in serial brain 18F-AV-45 PET scan among the FAD, familial mild cognitive impairment (FMCI), and sMCI and sAD patients.Results: Seven familial patients received a follow-up survey. The follow up duration for brain AV-45 PET was from 1.54 to 3.61 years. In 4 FMCI patients, an increased regional SUVR was noted, and the annual change rates were increased from 1.03% to 18.82%. However, a decreased regional SUVR was noted in 3 FAD patients and the annual change rates were from -2.62% to -16.03%. As compared with the sAD and sMCI patients, the annual change rate is statistically significant in FAD and FMCI patients respectively.Conclusions: The data indicate a biphasic course with an initial increase and then a decrease of SUVR in brain amyloid PET scan in familial APP mutation patients. The data also reveal that the novel Taiwan APP (D678H) mutation has a more amyloid burden than the sAD patients, particularly in an MCI stage. [ABSTRACT FROM AUTHOR]

Boron neutron capture therapy (BNCT), an attractive strategy for cancer treatment, can kill tumor cells and avoid injury to surrounding healthy cells. 4-Borono-2-[18F]fluorophenylalanine ([18F]FBPA) positron emission tomography (PET) is a reliable tool for patient screening. Due to the relatively low radiochemical yield when employing the electrophilic route, this study was able to develop a new method to produce no-carrier-added (NCA) [18F]FBPA and compare the biological characteristics with carrier-added (CA) characteristics. By starting from 4-bromo-2-nitrobenzaldehyde, NCA [18F]FBPA was prepared using radiofluorination, alkylation, borylation, and hydrolysis. Cellular uptake analyses, microPET imaging, and biodistribution analyses were conducted to characterize the biological properties of NCA and CA [18F]FBPA. The radiochemical yield of NCA [18F]FBPA was 20 % ± 6 % (decay corrected) with a radiochemical purity of >98 % and molar activity of 56 ± 15 GBq/μmol in a 100-min synthesis. The in vitro accumulation was significantly higher for NCA [18F]FBPA than for CA [18F]FBPA in both SAS and CT-26 cells. However, no apparent differences in tumor uptake were observed between NCA and CA [18F]FBPA-injected tumor-bearing mice. We successfully prepared NCA [18F]FBPA through nucleophilic substitution and achieved improved radiochemical yield and purity. We also demonstrated the effects of the amount of nonradioactive FBPA on in vitro cellular uptake and in vivo imaging studies. [Display omitted] [ABSTRACT FROM AUTHOR]

Regarding the increased incidence and high mortality rate of malignant melanoma, practical early-detection methods are essential to improve patients' clinical outcomes. In this study, we successfully prepared novel picolinamide–benzamide (18F-FPABZA) and nicotinamide–benzamide (18F-FNABZA) conjugates and determined their biological characteristics. The radiochemical yields of 18F-FPABZA and 18F-FNABZA were 26 ± 5% and 1 ± 0.5%, respectively. 18F-FPABZA was more lipophilic (log P = 1.48) than 18F-FNABZA (log P = 0.68). The cellular uptake of 18F-FPABZA in melanotic B16F10 cells was relatively higher than that of 18F-FNABZA at 15 min post-incubation. However, both radiotracers did not retain in amelanotic A375 cells. The tumor-to-muscle ratios of 18F-FPABZA-injected B16F10 tumor-bearing mice increased from 7.6 ± 0.4 at 15 min post-injection (p.i.) to 27.5 ± 16.6 at 3 h p.i., while those administered with 18F-FNABZA did not show a similarly dramatic increase throughout the experimental period. The results obtained from biodistribution studies were consistent with those derived from microPET imaging. This study demonstrated that 18F-FPABZA is a promising melanin-targeting positron emission tomography (PET) probe for melanotic melanoma. [ABSTRACT FROM AUTHOR]

Background: The 18F-THK-5351 radiotracer has been used to detect the in vivo tau protein distribution in patients with tauopathy, such as Alzheimer’s disease and corticobasal syndrome. In addition, 18F-THK-5351 can also monitor neuroinflammatory process due to high affinity to astrogliosis. We aimed to explore 18F-THK-5351 distribution patterns and characteristics in patients with recent ischemic stroke.Results: Fifteen patients received 18F-THK-5351 positron emission tomography (PET) and diffusion tensor imaging (DTI) approximately 3 months after ischemic stroke. A region of interest (ROI) was placed in the peri-ischemic area and was mirrored on the contralateral side as the control, and a proportional value was derived from the ratio of the peri-ischemic ROI value over the mirrored ROI value. Increased 18F-THK-5351 retention was observed in the areas around and remote from the stroke location. The proportional 18F-THK-5351 values were negatively correlated with the proportional fractional anisotropy values (r = − 0.39, P = 0.04).Conclusion: 18F-THK-5351 PET imaging provides a potential tool for in vivo visualization of the widespread ischemia-related changes associated with a microstructural disruption in recent ischemic stroke patients. [ABSTRACT FROM AUTHOR]