Sensitivity-encoded spectroscopic imaging (SENSE-SI) reduces scanning time by using multiple coils for parallel signal acquisition. Significant artifacts could be induced by SENSE-SI, mainly due to the low-resolution nature of spectroscopic imaging. The present study introduces a novel method to reduce the artifacts. High-resolution sensitivity maps are used in low-resolution SENSE reconstruction. An intermediate unaliased image is obtained after SENSE reconstruction. Based on the intermediate image, the sensitivity maps are optimized and then the SENSE reconstruction is performed again. The final unaliased image has significantly reduced artifacts.
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http://dx.doi.org/10.1002/mrm.20325 | DOI Listing |
MAGMA
December 2024
Department of Radiology and Medical Informatics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Objectives: Phosphorus-31 magnetic resonance spectroscopic imaging (P-MRSI) is a non-invasive tool for assessing cellular high-energy metabolism in-vivo. However, its acquisition suffers from a low sensitivity, which necessitates large voxel sizes or multiple averages to achieve an acceptable signal-to-noise ratio (SNR), resulting in long scan times.
Materials And Methods: To overcome these limitations, we propose an acquisition and reconstruction scheme for FID-MRSI sequences.
Nat Prod Res
December 2024
Department of General, Organic and Biomedical Chemistry, Faculty of Medicine and Pharmacy, University of Mons, NMR and Molecular Imaging Laboratory, Mons, Belgium.
Propolis is a resinous material collected by different bee species from various plant exudates and used to seal holes in honeycombs, smoothen the internal walls, embalm intruders, improve health and prevent diseases. From its -hexane extract, eight compounds were isolated and characterised as: mangiferonic acid (); 1-hydroxymangiferonic acid (), new natural product; mangiferolic acid(); 27-hydroxymangiferolic acid (), reported here for the first time as propolis constituent; 27-hydroxymangiferonic acid (); -amyrin (); -amyrin () and lupeol (). The chemical structures of the isolated compounds were elucidated using spectroscopic methods, such as 1D and 2D-NMR, mass spectrometry and comparison with previous published reports.
View Article and Find Full Text PDFLaser Photon Rev
October 2024
Harvard Medical School, Boston, MA 02114, USA; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Cardiology, Erasmus Medical Center, Rotterdam GD3015, The Netherlands; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Photoacoustic microscopy (PAM) is a high-resolution and non-invasive imaging modality that provides optical absorption contrast. By employing dual- or multiple-wavelength excitation, PAM extends its capabilities to offer valuable spectroscopic information. To achieve efficient multispectral PAM imaging, an essential requirement is a light source characterized by a high repetition rate and switching rate, a ≈microjoule pulse energy, and a ≈nanosecond pulse duration.
View Article and Find Full Text PDFSensitive detection of incident acoustic waves over a broad frequency band offers a faithful representation of photoacoustic pressure transients of biological microstructures. Here, we propose a plasmon waveguide resonance sensor for responding to the photoacoustic impulses. By sequentially depositing Au, MgF, and SiO films on a coverslip, a composite waveguide layer produces a tightly confined optical evanescent field at the SiO-water interface with extremely strong electric field intensity, enabling the retrieval of photoacoustic signals with an estimated noise-equivalent-pressure (NEP) sensitivity of ∼92 Pa and a -6-dB bandwidth of ∼208 MHz.
View Article and Find Full Text PDFRadiology
December 2024
From the Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK (L.E.M.F., M.P.C., M.J., A.S., Z.A., S.N., D.J.T., B.R., L.V.); Oncology and Haematology Centre, Churchill Hospital, Oxford, UK (A.S.); Axcella Therapeutics, Cambridge, Mass (K.A.); and Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia (L.V.).
Background Emerging evidence suggests mitochondrial dysfunction may play a role in the fatigue experienced by individuals with post-COVID-19 condition (PCC), commonly called long COVID, which can be assessed using MR spectroscopy. Purpose To compare mitochondrial function between participants with fatigue-predominant PCC and healthy control participants using MR spectroscopy, and to investigate the relationship between MR spectroscopic parameters and fatigue using the 11-item Chalder fatigue questionnaire. Materials and Methods This prospective, observational, single-center study (June 2021 to January 2024) included participants with PCC who reported moderate to severe fatigue, with normal blood test and echocardiographic results, alongside control participants without fatigue symptoms.
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