We report qualitative and quantitative evaluation and verification studies of the bipolar phase gradient modulation method for true MR imaging of internal flow and motion velocities. Velocity encoding modulations provide speed-of-motion and direction-sensitive images using special phase-sensitive reconstructions. True motion MR imaging does not depend upon subject parameters, T1 or T2, nor upon selective active-volume time-of-flight calculations, nor is it limited strictly to fluid-flow velocities. Conventional MR sequences often induce strong accidental phase gradient modulations that can cause severe artifacts in conventional MR scans and limit the useful sensitivities of true motion MR. Multiple steps of velocity encoding allow resolution of separate elements of the velocity spectrum, and enable suppression of all such phase-artifact difficulties. Some view-to-view phase inconsistencies are intrinsic to the subject being scanned, e.g., strong motion variations during the heart cycle; limitations due to such effects require external modifications in the scanning, such as cardiac gating. Since conventional density information remains in the data, independent of velocity encoding modulations, we suggest a multiple encoding sequence and saving the MR raw data. These evaluations and verifications demonstrate exciting potential in clinical application for the phase gradient modulation method of true flow and motion MR imaging.
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http://dx.doi.org/10.1148/radiology.154.2.3966130 | DOI Listing |
PLoS One
January 2025
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan.
Background: Chronic respiratory failure (CRF) is a critical complication in patients with chronic obstructive pulmonary disease (COPD) and is characterized by an increase in the arterial-alveolar oxygen gradient (A-aDO2). The long-term trajectory and prognostic significance remain unclear. This study aimed to assess the prognostic impact of A-aDO2 and elucidate its trajectory over ten years.
View Article and Find Full Text PDFJ Clin Gastroenterol
January 2025
The Third Central Hospital of Tianjin, Hedong District.
Goals: To explore dynamic contrast-enhanced ultrasound (CEUS) parameters in predicting hepatic vein pressure gradient (HVPG) for patients with liver cirrhosis (LC).
Background: Noninvasive diagnosis of HVPG remains a challenge.
Study: This prospective study included patients with LC undergoing hepatic vein catheterization and pressure measurement at the hospital from May 2021 to January 2023.
J Sep Sci
January 2025
Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Toruń, Poland.
Oligonucleotides (ONs) are an increasingly popular category of molecules in the pharmaceutical landscape, particularly attractive for the treatment of genetic and rare diseases. However, analyzing these molecules presents significant challenges, due to their highly hydrophilic nature, multiple negative charges, and the presence of closely related impurities resulting from the complex solid-phase synthesis process. Ion pairing reverse-phase liquid chromatography (IP-RPLC) is the preferred technique for ONs analysis but is not ideal for mass spectrometry (MS) coupling.
View Article and Find Full Text PDFTerahertz reconfigurable intelligent surfaces (RIS) stand out from conventional phased arrays thanks to their unique electromagnetic properties and intelligent interconnect paradigms. They are a vital technology for terahertz wireless communication and radar detection systems. Compared with 1-bit coding metasurfaces, 2-bit coding metasurfaces offer significant advantages such as single beam steering and reduced quantization errors.
View Article and Find Full Text PDFThe traditional phase shift measurement technique necessitates two orthogonally oriented fringe patterns to complete the phase measurement, which is time-consuming, and the phase modulation of the traditional fringe image exhibits only a gradient change in a single direction of the horizontal-vertical fringes, or a smooth gradient change in the tangential direction of the circular fringes. To enhance the measurement speed and improve the adaptability to large curvature measured specular surfaces, this paper proposes a phase measurement deflectometry (PMD) technique based on composite circular fringes. The composite circular fringes demonstrate a steeper slope in the phase change, enabling the acquisition of finer surface features under identical measurement conditions, effectively improving the detection sensitivity to small shape changes and enhancing the ability to discern fine details.
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