Clausenthuesen3659
Mean MRFDG ranged from 23.1696μmol/100g/min in the parietal cortex to 0.5945μmol/100g/min in the lung. Four groups of organs with similar kinetic characteristics were identified (1) the cerebral white matter, lung, liver, muscle, bone, and bone marrow; (2) cerebral and cerebellar cortex; (3) LV myocardium and thyroid; and (4) pancreas, spleen, and kidney.
The kinetic rates and MRFDG significantly differed among organs. The kinetic metrics of FDG parameters in normal organs can serve as a reference for future dynamic PET imaging and research.
The kinetic rates and MRFDG significantly differed among organs. The kinetic metrics of FDG parameters in normal organs can serve as a reference for future dynamic PET imaging and research.
Despite growing evidence of a superior diagnostic performance of
Ga-PSMA-11 over
F-fluorocholine (FCH) PET/CT, the number of PET/CT centres able to label on site with gallium-68 is still currently limited. Therefore, patients with biochemical recurrence (BCR) of prostate cancer frequently undergo FCH as the 1st-line PET/CT. Actually, the positivity rate (PR) of a second-line PSMA-11 PET/CT in case of negative FCH PET/CT has only been reported in few short series, in a total of 185 patients. Our aims were to check (1) whether the excellent PR reported with PSMA-11 is also obtained in BCR patients whose recent FCH PET/CT was negative or equivocal; (2) in which biochemical and clinical context a high PSMA-11 PET/CT PR may be expected in those patients, in particular revealing an oligometastatic pattern; (3) whether among the various imaging protocols for PSMA-11 PET/CT used in France, one yields a significantly highest PR; (4) the tolerance of PSMA-11.
Six centres performed
Ga-PSMA-11 PET/CTs during thfor sPSA less then 1 ng/mL but in a slightly lower PR for sPSA ≥ 1 ng/mL, probably because FCH performs rather well at this sPSA and very occult BCR was over-represented in our cohort. An oligometastatic pattern paving the way to targeted therapy was observed in one fourth to one third of the cases, according to the clinico-biochemical context of the BCR. Systematic dual or triple acquisition time points or administration of a contrast agent and/or furosemide did not bring a significant added value for PSMA-11 PET/CT positivity and should be decided on individual bases.
Total thyroidectomy and risk-adapted 131-radioiodine therapy (RaIT) are the treatments of choice in differentiated thyroid cancer (DTC) patients. The response to treatments is assessed 6-12months after RaIT. However, thyroglobulin (Tg) values obtained just before RaIT also provide reliable informations on patients'outcome. As available data were mostly obtained in hypothyroid status, we evaluated the predictive role of preablation-Tg in patients underwent RaIT after rhTSH stimulation.
We enrolled 299 low-to-intermediate risk DTC patients underwent rhTSH-stimulated RaIT (standard protocol). S63845 Serum Tg levels were measured before rhTSH administration (basal Tg), before RaIT (early-stimulated Tg), and 2days after RaIT (late-stimulated Tg). The early response assessment was done 12months after RaIT according to 2015 American Thyroid Association (2015 ATA) criteria.
Most patients (277/299, 92.6%) had an excellent response (ER) to RaIT, while 15/299 (5.1%) and 7/299 (2.3%) patients showed biochemical incompleteresponse to primary treatment of DTC.
Cardiac resynchronization therapy (CRT) is effective in selective heart failure (HF) patients, but non-response rate remains high. Positron emission tomography (PET) may provide a better insight into the pathophysiology of left ventricular (LV) remodeling; however, its role for evaluating and selecting patients for CRT remains uncertain.
We investigated if regional LV glucose metabolism in combination with myocardial scar could predict response to CRT.
Consecutive CRT-eligible HF patients underwent echocardiography, cardiac magnetic resonance (CMR), and
F-fluorodeoxyglucose (FDG) PET within 1week before CRT implantation. Echocardiography was additionally performed 12months after CRT and end-systolic volume reduction ≥ 15% was defined as CRT response. Septal-to-lateral wall (SLR) FDG uptake ratio was calculated from static FDG images. Late gadolinium enhancement (LGE) CMR was analyzed semi-quantitatively to define scar extent.
We evaluated 88 patients (67 ± 10 years, 72% males).
F-FDG SLR showed a tively be used to optimize patient selection.
FDG SLR can be used as a predictor of CRT response and combined with septal scar extent, CRT responders can be distinguished from non-responders with high diagnostic accuracy. Further studies are needed to verify whether this imaging approach can prospectively be used to optimize patient selection.
While sampled or short-frame realizations have shown the potential power of deep learning to reduce radiation dose for PET images, evidence in true injected ultra-low-dose cases is lacking. Therefore, we evaluated deep learning enhancement using a significantly reduced injected radiotracer protocol for amyloid PET/MRI.
Eighteen participants underwent two separate
F-florbetaben PET/MRI studies in which an ultra-low-dose (6.64 ± 3.57 MBq, 2.2 ± 1.3% of standard) or a standard-dose (300 ± 14 MBq) was injected. The PET counts from the standard-dose list-mode data were also undersampled to approximate an ultra-low-dose session. A pre-trained convolutional neural network was fine-tuned using MR images and either the injected or sampled ultra-low-dose PET as inputs. Image quality of the enhanced images was evaluated using three metrics (peak signal-to-noise ratio, structural similarity, and root mean square error), as well as the coefficient of variation (CV) for regional standard uptake value ratios (SUVRs). potential to reduce dose significantly for amyloid imaging.
Deep learning methods can synthesize diagnostic-quality PET images from ultra-low injected dose simultaneous PET/MRI data, demonstrating the general validity of sampled realizations and the potential to reduce dose significantly for amyloid imaging.
Synaptic abnormalities are associated with many brain disorders. Recently, we developed a novel synaptic vesicle glycoprotein 2A (SV2A) radiotracer [
F]SynVesT-1 and demonstrated its excellent imaging and binding properties in nonhuman primates. The aim of this study was to perform dosimetry calculations in nonhuman primates and to evaluate this tracer in humans and assess its test-retest reliability in comparison with [
C]UCB-J.
Three rhesus monkeys underwent whole body dynamic PET scanning to estimate the absorbed dose. PET scans in six healthy human subjects were acquired. Time-activity curves (TACs) were generated with defined regions of interest (ROI). Reproducibility of distribution volume (V
) values and its sensitivity to scan duration were assessed with the one-tissue compartment (1TC) model. Non-displaceable binding potential (BP
) was calculated using centrum semiovale as the reference region.
The dosimetry study showed high uptake in the urinary bladder and brain. In humans, [
F]SynVesT-1 displayed high uptake with maximum SUV of ~10 and appropriate kinetics with a quick rise in tracer uptake followed by a gradual clearance.
