Background: Alzheimer's disease (AD) is characterized by impaired inhibitory circuitry and GABAergic dysfunction, which is associated with reduced fast brain oscillations in the gamma band (γ, 30-90 Hz) in several animal models. Investigating such activity in human patients could lead to the identification of novel biomarkers of diagnostic and prognostic value. The current study aimed to test a multimodal "Perturbation-based" transcranial Alternating Current Stimulation-Electroencephalography (tACS)-EEG protocol to detect how responses to tACS in AD patients correlate with patients' clinical phenotype.
View Article and Find Full Text PDFRadiopharmaceutical therapy (RPT) is an emerging prostate cancer treatment that delivers radiation to specific molecules within the tumor microenvironment (TME), causing DNA damage and cell death. Given TME heterogeneity, it's crucial to explore RPT dosimetry and biological impacts at the cellular level. We integrated spatial transcriptomics (ST) with computational modeling to investigate the effects of RPT targeting prostate-specific membrane antigen (PSMA), fibroblast activation protein (FAP), and gastrin-releasing peptide receptor (GRPR) each labelled with beta-emitting lutetium-177 (Lu) and alpha-emitting actinium-225 (Ac).
View Article and Find Full Text PDFProc IEEE Int Symp Biomed Imaging
May 2024
Positron Emission Tomography (PET) is a valuable imaging method for studying molecular-level processes in the body, such as hyperphosphorylated tau (p-tau) protein aggregates, a hallmark of several neurodegenerative diseases including Alzheimer's disease. P-tau density and cerebral perfusion can be quantified from PET data using tracer kinetic modeling techniques. However, noise in PET images leads to uncertainty in the estimated kinetic parameters.
View Article and Find Full Text PDFIEEE Trans Radiat Plasma Med Sci
November 2024
Motion is unavoidable in dynamic [F]-MK6240 Positron Emission Tomography (PET) imaging, especially in Alzheimer's disease (AD) research requiring long scan duration. To understand how motion correction affects quantitative analysis, we investigated two approaches: II-MC, which corrects for both inter-frame and intra-frame motion, and IO-MC, which only corrects for inter-frame motion. These methods were applied to 83 scans from 34 subjects, and we calculated distribution volume ratios (DVR) using the multilinear reference tissue model with two parameters (MRTM2) in tau-rich brain regions.
View Article and Find Full Text PDFIEEE Trans Biomed Eng
October 2024
Unlabelled: Receptor occupancy (RO) studies using PET neuroimaging play a critical role in the development of drugs targeting the central nervous system (CNS). The conventional approach to estimate drug receptor occupancy consists in estimation of binding potential changes between two PET scans (baseline and post-drug injection). This estimation is typically performed separately for each scan by first reconstructing dynamic PET scan data before fitting a kinetic model to time activity curves.
View Article and Find Full Text PDFIEEE Nucl Sci Symp Conf Rec (1997)
September 2024
Diffusion models (DM) built from a hierarchy of denoising autoencoders have achieved remarkable progress in image generation, and are increasingly influential in the field of image restoration (IR) tasks. In the meantime, its backbone of autoencoders also evolved from UNet to vision transformer, e.g.
View Article and Find Full Text PDFIEEE Nucl Sci Symp Conf Rec (1997)
September 2024
Delineating lesions and anatomical structure is important for image-guided interventions. Point-supervised medical image segmentation (PSS) has great potential to alleviate costly expert delineation labeling. However, due to the lack of precise size and boundary guidance, the effectiveness of PSS often falls short of expectations.
View Article and Find Full Text PDFIEEE Nucl Sci Symp Conf Rec (1997)
September 2024
Recent advances in deep learning (DL) have greatly improved the performance of positron emission tomography (PET) denoising performance. However, DL model performance can vary a lot across subjects, due to the large variability of the count levels and spatial distributions. A generalizable DL model that mitigates the subject-wise variations is highly expected toward a reliable and trustworthy system for clinical application.
View Article and Find Full Text PDFProc SPIE Int Soc Opt Eng
February 2024
In this work, we aim to predict the survival time (ST) of glioblastoma (GBM) patients undergoing different treatments based on preoperative magnetic resonance (MR) scans. The personalized and precise treatment planning can be achieved by comparing the ST of different treatments. It is well established that both the current status of the patient (as represented by the MR scans) and the choice of treatment are the cause of ST.
View Article and Find Full Text PDFProc IEEE Int Symp Biomed Imaging
May 2024
The off-the-shelf model for unsupervised domain adaptation (OSUDA) has been introduced to protect patient data privacy and intellectual property of the source domain without access to the labeled source domain data. Yet, an off-the-shelf diagnosis model, deliberately compromised by backdoor attacks during the source domain training phase, can function as a parasite-host, disseminating the backdoor to the target domain model during the OSUDA stage. Because of limitations in accessing or controlling the source domain training data, OSUDA can make the target domain model highly vulnerable and susceptible to prominent attacks.
View Article and Find Full Text PDFPurpose: This review systematically investigates the role of radiomics in radiotherapy, with a particular emphasis on the use of quantitative imaging biomarkers for predicting clinical outcomes, assessing toxicity, and optimizing treatment planning. While the review encompasses various applications of radiomics in radiotherapy, it particularly highlights its potential for guiding reirradiation of recurrent cancers.
Methods: A systematic review was conducted based on a Medline search with the search engine PubMed using the keywords "radiomics or radiomic" and "radiotherapy or reirradiation".
Purpose: To develop a new method for free-breathing 3D extracellular volume (ECV) mapping of the whole heart at 3 T.
Methods: A free-breathing 3D cardiac ECV mapping method was developed at 3 T. T mapping was performed before and after contrast agent injection using a free-breathing electrocardiogram-gated inversion recovery sequence with spoiled gradient echo readout.
Parvalbumin-positive (PV+) basket neurons are fast-spiking, non-adapting inhibitory interneurons whose oscillatory activity is essential for regulating cortical excitation/inhibition balance. Their dysfunction results in cortical hyperexcitability and gamma rhythm disruption, which have recently gained substantial traction as contributing factors as well as potential therapeutic targets for the treatment of Alzheimer's Disease (AD). Recent evidence indicates that PV+ cells are also impaired in Frontotemporal Dementia (FTD) and Dementia with Lewy bodies (DLB).
View Article and Find Full Text PDFDiagnostics (Basel)
September 2024
In time-of-flight positron emission tomography (TOF-PET), a coincidence time resolution (CTR) below 100 ps reduces the angular coverage requirements and, thus, the geometric constraints of the scanner design. Among other possibilities, this opens the possibility of using flat-panel PET detectors. Such a design would be more cost-accessible and compact and allow for a higher degree of modularity than a conventional ring scanner.
View Article and Find Full Text PDF$\textbf{Purpose:}$ To develop a new method for free-breathing 3D extracellular volume (ECV) mapping of the whole heart at 3T. $\textbf{Methods:}$ A free-breathing 3D cardiac ECV mapping method was developed at 3T. T1 mapping was performed before and after contrast agent injection using a free-breathing ECG-gated inversion-recovery sequence with spoiled gradient echo readout.
View Article and Find Full Text PDFThe human tongue exhibits an orchestrated arrangement of internal muscles, working in sequential order to execute tongue movements. Understanding the muscle coordination patterns involved in tongue protrusive motion is crucial for advancing knowledge of tongue structure and function. To achieve this, this work focuses on five muscles known to contribute to protrusive motion.
View Article and Find Full Text PDFProc SPIE Int Soc Opt Eng
February 2024
Understanding the relationship between tongue motion patterns during speech and their resulting speech acoustic outcomes-i.e., articulatory-acoustic relation-is of great importance in assessing speech quality and developing innovative treatment and rehabilitative strategies.
View Article and Find Full Text PDFA National Institutes of Health (NIH) and U.S. Department of Energy (DOE) Office of Science virtual workshop on shared general topics was held in July of 2021 and reported on in this publication in January of 2023.
View Article and Find Full Text PDFDelineating lesions and anatomical structure is important for image-guided interventions. Point-supervised medical image segmentation (PSS) has great potential to alleviate costly expert delineation labeling. However, due to the lack of precise size and boundary guidance, the effectiveness of PSS often falls short of expectations.
View Article and Find Full Text PDFIntroduction: Understanding early neuropathological changes and their associations with cognition may aid dementia prevention. This study investigated associations of cerebral amyloid and tau positron emission tomography (PET) retention with cognition in a predominately middle-aged community-based cohort and examined factors that may modify these relationships.
Methods: C-Pittsburgh compound B amyloid and F-flortaucipir tau PET imaging were performed.
Background: Higher midlife physical activity engagement has been associated with lower dementia risk in late life. However, the underlying mechanisms contributing to the protective effect remain unclear.
Objective: The goal of the current study was to evaluate the associations of physical activity with cerebral amyloid-β (Aβ) and tau in a predominately middle-aged community-based cohort, as well as to explore whether the associations differ by sex or age.
Positron emission tomography (PET) imaging employs positron-emitting radioisotopes to visualize biological processes in living subjects with high sensitivity and quantitative accuracy. As the most translational molecular imaging modality, PET can detect and image a wide range of radiotracers with minimal or no modification to parent drugs or targeting molecules. This Perspective provides a comprehensive analysis of developing PET radioligands using allosteric modulators for the metabotropic glutamate receptor subtype 4 (mGluR4) as a therapeutic target for neurological disorders.
View Article and Find Full Text PDFMagn Reson Med
October 2024
Purpose: To develop a practical method to enable 3D T mapping of brain metabolites.
Theory And Methods: Due to the high dimensionality of the imaging problem underlying metabolite T mapping, measurement of metabolite T values has been currently limited to a single voxel or slice. This work achieved 3D metabolite T mapping by leveraging a recent ultrafast MRSI technique called SPICE (spectroscopic imaging by exploiting spatiospectral correlation).
People with human immunodeficiency virus (HIV, PWH) face an increased risk of cardiovascular disease (CVD) compared to the general population. We previously demonstrated that people with (versus without) HIV have higher macrophage-specific arterial infiltration in relation to systemic monocyte activation. We now show that select T lymphocyte subpopulations (naïve CD4 + , effector memory CD4 + , and central memory CD8 + ) are differentially associated with macrophage-specific arterial infiltration among participants with versus without HIV, with evidence of interaction by HIV status.
View Article and Find Full Text PDFBackground: Associations of plasma total tau levels with future risk of AD have been described.
Objective: To examine the extent to which plasma tau reflects underlying AD brain pathology in cognitively healthy individuals.
Methods: We examined cross-sectional associations of plasma total tau with 11C-Pittsburgh Compound-B (PiB)-PET and 18F-Flortaucipir (FTP)-PET in middle-aged participants at the community-based Framingham Heart Study.