This study describes a new approach for material decomposition in x-ray imaging, utilizing phase contrast both to increase sensitivity to weakly attenuating samples and to act as a complementary measurement to attenuation, therefore allowing two overlaid materials to be separated. The measurements are captured using the single-exposure, single-grid x-ray phase contrast imaging technique, with a novel correction that aims to remove propagation-based phase effects seen at sharp edges in the attenuation image. The use of a single-exposure technique means that images can be collected in a high-speed sequence. Results are shown for both a known two-material sample and for a biological specimen.
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http://dx.doi.org/10.1364/OL.389770 | DOI Listing |
Eur Radiol
January 2025
Department of Diagnostic and Interventional Radiology, University Hospital Augsburg, Augsburg, Germany.
Objectives: The purpose of this study was to evaluate whether the iodine contrast in blood and solid organs differs between men and women and to evaluate the effect of BMI, height, weight, and blood volume (BV) on sex-specific contrast in staging CT.
Materials And Methods: Patients receiving a venous-phase thoracoabdominal Photon-Counting Detector CT (PCD-CT) scan with 100- or 120-mL CM between 08/2021 and 01/2022 were retrospectively included in this single-center study. Image analysis was performed by measuring iodine contrast in the liver, portal vein, spleen, left atrium, left ventricle, pulmonary trunk, ascending and descending aorta on spectral PCD-CT datasets.
Cancer Res
December 2024
Lunenfeld-Tanenbaum Research Institute, Toronto, Canada.
IDH-mutant low-grade gliomas (LGGs) are slow-growing brain tumors that frequently progress to aggressive high-grade gliomas that have dismal outcomes. In a recent study, Wu and colleagues provide critical insights into the mechanisms underlying malignant progression by analyzing single-cell gene expression and chromatin accessibility across different tumor grades. Their findings support a two-phase model: in early stages, tumors are primarily driven by oligodendrocyte precursor-like cells and epigenetic alterations that silence tumor suppressors like CDKN2A and activate oncogenes such as PDGFRA.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Grossman School of Medicine, New York, NY, USA.
Background: Amyloid related imaging abnormalities (ARIA), a group of neuropathological features seen in anti-amyloid immunotherapy patients, arises partly from CAA (Aβ buildup in blood vessels). Squirrel monkeys (SQMs), developing prominent age-related CAA exceeding brain Aβ, offer a unique NHP model for ARIA study. Evaluating edema-related neurobiological defects (ARIA-E) involves preferential use of T-weighted (T-w) and flow-attenuated inversion recovery (FLAIR) MRI while T*-weighted (T*-w) MRI is better suited for investigating iron-related pathology like microbleeds, hemorrhaging, and iron-homing in plaques.
View Article and Find Full Text PDFBackground: Post-COVID cognitive dysfunctions, impacting attention, memory, and learning, might be linked to inflammation-induced blood-brain barrier (BBB) impairment. This study explores post-COVID BBB permeability changes using a non-contrast water-exchange based MRI and their associations with blood Alzheimer's biomarkers.
Method: Sixty-seven participants were classified based on COVID (COV) and cognitive (COG) statuses into three groups: COV+/COG- (n=34), COV+/COG+ (n=23), and COV- (n=10) for comparisons (COV+: Laboratory-verified SARS-CoV-2 infection; COV-: No history of SARS-CoV-2 infection and negative SARS-CoV-2 nucleocapsid antibody test.
J Neuroimaging
January 2025
Department of Radiology, Division of Neuroradiology, Johns Hopkins Medical Center, Baltimore, Maryland, USA.
Introduction: The venous outflow profile (VOP) is a crucial yet often overlooked aspect affecting stroke outcomes. It plays a major role in the physiopathology of acute cerebral ischemia, as it accounts for both the upstream arterial collaterals and cerebral microperfusion. This enables it to circumvent the limitations of various arterial collateral evaluation systems, which often fail to consider impaired autoregulation and its impact on cerebral blood flow at the microcirculatory levels.
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