Purpose: This phantom study aimed to determine the optimal acquisition window size for phase-based respiratory gating in silicon photomultiplier (SiPM)-based fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and its acquisition time in respiratory-gated imaging with the optimal window size.
Methods: Images of a moving NEMA IEC Body Phantom Set with hot spheres were acquired. First, the tumor volume and the maximum standardized uptake value (SUV) of images reconstructed using a different window size were evaluated to define the optimal window size. Second, the quality of the images reconstructed using the optimal window size and different acquisition times was evaluated using the detectability score of the 10-mm hot sphere and physical indices.
Results: The volume and the SUV of the 10-mm hot sphere were improved when the window size was narrow, and there were no significant differences among images reconstructed using a window size narrower than 20%. To reconstruct an image using the 20% window size, an acquisition time of 5 min was required to visualize the 10-mm hot sphere.
Conclusions: The optimal window size for phase-based respiratory gating is 20%. Further, an acquisition time of 5 min should be taken for respiratory-gated imaging with the 20% window size on SiPM-based FDG-PET/CT.
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http://dx.doi.org/10.6009/jjrt.2020_JSRT_76.8.795 | DOI Listing |
J Clin Neurophysiol
December 2024
Human Brain Mapping Program, University of Pittsburgh Medical Centre, Pittsburgh, Pennsylvania, U.S.A.; and.
Objectives: Our study aimed to compare signal characteristics of subdural electrodes (SDE) and depth stereo EEG placed within a 5-mm vicinity in patients with drug-resistant epilepsy. We report how electrode design and placement collectively affect signal content from a shared source between these electrode types.
Methods: In subjects undergoing invasive intracranial EEG evaluation at a surgical epilepsy center from 2012 to 2018, stereo EEG and SDE electrode contacts placed within a 5-mm vicinity were identified.
Background: Current models of AD posit neurodegeneration and cognitive decline occur downstream in a pathophsyiological cascade initiated by amyloid (Aβ), yet lifespan research suggests the brain regions and cognitive functions impacted most by AD exhibit the steepest, steady decline rates across life. We hypothesised adult lifespan neurodegeneration in AD-vulnerable brain regions would predict memory decline rates detectable in healthy adults as they age, independent of Aβ.
Method: We combined MRI scans across three large longitudinal cohorts of cognitively healthy adults (age 30-96 years) to estimate brain change relative to the change expected given a person's age (2-14 timepoints; 4125 scans of 1027 individuals; cohorts: LCBC, the Berkeley Aging Cohort Study [BACS]; ADNI [stable cognitively healthy]).
Background: Renal atrophy may reflect an end organ consequence of chronic vascular disease. Renal volume loss may therefore provide a window into brain aging and Alzheimer disease risk.
Method: We obtained whole-body 1.
Background: Preclinical Alzheimer's disease research has gained traction as a potential point of intervention, though it is relatively unknown how early stages of the disease impact cortical health. The following study utilizes optical imaging methods (Figure 1) to characterize changes in neuronal, glutamate, and hemodynamic activities in a preclinical amyloidosis mouse model of the disease.
Method: Five (n = 5; 2 females & 3 males) APPswe/PS1dE9 x Thy1-jRGECO1a double transgenic mice were breed for whole-brain fluorescent imaging of neuronal activity.
Background: We showed that plasma GFAP (a proxy of astrocyte reactivity) abnormality is key to unleashing Aβ effects on tau phosphorylation in preclinical AD. This suggests that selecting cognitively unimpaired(CU) individuals with both high Aβ and plasma GFAP could offer an early time window in the disease, but with an increased risk of developing tau pathology. Here, we tested the utility of plasma GFAP for population enrichment in clinical trials focusing on CU individuals.
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