Purpose: The main objective of this study is to develop a 2D single-shot radial-DWI (2D ss-rDWI) technique to reduce motion artifacts and geometric distortion in DW images.
Method: A diffusion-preparation module is developed and applied prior to the data acquisition. Because the diffusion-prepared longitudinal magnetization is measured over multiple RF excitations in each shot, 2D ss-rDWI is subject to low signal-to-noise ratio (SNR). We used variable-flip angle (VFA), random view ordering (RVO), and sliding spokes, and compared the performances to constant flip angle (CFA), smooth view ordering (SVO), and identical spoke averaging, respectively. For each technique, we performed numerical simulation and MRI experiments on a fluid phantom as well as in-vivo human brain studies with a 3 T MRI system.
Results: Using VFA, optimal SNR was acquired for 2D ss-rDWI. Using SVO, the high signal is clustered at specific quadrant in 2D k-space: the first quadrant using high initial flip angle or the last quadrant using the low flip angle. This clustered signal in k-space led to geometric distortion in image space. 2D ss-rDWI using RVO spreads the high signaled spokes over all angular directions and removes the view-order-related distortion. The in-vivo images using 2D ss-rDWI with VFA and RVO show no geometric distortion at the skull base brain, but greatly reduced SNR compared with those using 2D ss-DWEPI.
Conclusion: 2D ss-rDWI is optimized by using VFA with RVO. The resultant DWI using 2D ss-rDWI is insensitive to motion-induced artifacts and geometric distortion. Even with low SNR, it may be useful for DWI of organs limited by severe susceptibility-induced geometric distortion.
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http://dx.doi.org/10.1016/j.mri.2019.04.008 | DOI Listing |
Transl Vis Sci Technol
January 2025
Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA.
Purpose: Although the lens undoubtedly plays a major role in presbyopia, altered lens function could be in part secondary to age-related changes of the ciliary muscle. Ciliary muscle changes with accommodation have been quantified using optical coherence tomography, but so far these studies have been limited to quantifying changes in ciliary muscle thickness, mostly at static accommodative states. Quantifying ciliary muscle thickness changes does not effectively capture the dynamic anterior-centripetal movement of the ciliary muscle during accommodation.
View Article and Find Full Text PDFWater Res
January 2025
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; College of Environment and Resources, Xiangtan University, Xiangtan, Hunan 411105, PR China. Electronic address:
A sustainable supply of lithium from salt-lake brines is necessary due to the surge in demand of the lithium-battery market. However, the presence of coexisting ions, particularly Na, poses a significant challenge due to the similarities in charge, electronic structure, and hydrated size. The electrochemical system with manganese (Mn)-based lithium-ion (Li) sieves electrodes is a promising method for Li recovery, but often suffers from geometric configuration distortion, which reduces their selectivity and capacity.
View Article and Find Full Text PDFCureus
December 2024
Neurological Surgery, Jersey Shore Medical Center, Neptune, USA.
Introduction The Synaptive magnetic resonance imaging (MRI) system (Synaptive Medical, Toronto, Canada) is a midfield 0.5 T head-only scanner for imaging the head and neck in adults and pediatrics. The system received US FDA and Health Canada clearance for clinical use in 2020.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Background: Diffusion-weighted (DW) turbo-spin-echo (TSE) imaging offers improved geometric fidelity compared to single-shot echo-planar-imaging (EPI). However, it suffers from low signal-to-noise ratio (SNR) and prolonged acquisition times, thereby restricting its applications in diagnosis and MRI-guided radiotherapy (MRgRT).
Purpose: To develop a joint k-b space reconstruction algorithm for concurrent reconstruction of DW-TSE images and the apparent diffusion coefficient (ADC) map with enhanced image quality and more accurate quantitative measurements.
Nat Commun
January 2025
Department of Chemistry, Michigan State University, East Lansing, Michigan, USA.
The formation of following the double ionization of small organic compounds via a roaming mechanism, which involves the generation of H and subsequent proton abstraction, has recently garnered significant attention. Nonetheless, a cohesive model explaining trends in the yield of characterizing these unimolecular reactions is yet to be established. We report yield and femtosecond time-resolved measurements following the strong-field double ionization of CHX molecules, where X = OD, Cl, NCS, CN, SCN, and I.
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