Purpose: Echo planar imaging (EPI) is the primary sequence for functional and diffusion MRI. In fetal applications, the large field of view needed to encode the maternal abdomen leads to prolonged EPI readouts, which may be further extended due to safety considerations that limit gradient performance. The resulting images become very sensitive to water-fat shift and susceptibility artefacts. The purpose of this study was to reduce artefacts and increase stability of EPI in fetal brain imaging, balancing local field homogeneity across the fetal brain with longer range variations to ensure compatibility with fat suppression of the maternal abdomen.
Methods: Spectral Pre-saturation with Inversion-Recovery (SPIR) fat suppression was optimized by investigating SPIR pulse frequency offsets. Subsequently, fetal brain EPI data were acquired using image-based (IB) shimming on 6 pregnant women by (1) minimizing B field variations within the fetal brain (localized IB shimming) and (2) with added constraint to limit B variation in maternal fat (fat constrained IB shimming).
Results: The optimal offset for the SPIR pulse at 3 Tesla was 550 Hz. Both shimming approaches had similar performances in terms of B homogeneity within the brain, but constrained IB shimming enabled higher fat suppression efficiency.
Conclusion: Optimized SPIR in combination with constrained IB shimming can improve maternal fat suppression while minimizing EPI distortions in the fetal brain.
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http://dx.doi.org/10.1002/mrm.27375 | DOI Listing |
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Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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College of Veterinary Medicine, South China Agricultural University, Guangzhou, China; Guangdong Research Center for Veterinary Traditional Chinese Medicine and Natural Medicine Engineering Technology, Guangzhou, China. Electronic address:
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Nutritional Sciences and Toxicology Department, University of California Berkeley, Berkeley, CA 94720, US.
Adipocyte hypertrophy significantly contributes to insulin resistance and metabolic dysfunction. Our previous research established JMJD8 as a mediator of insulin resistance, noting its role in promoting adipocyte hypertrophy within an autonomous adipocyte context. Nevertheless, the precise mechanisms underlying this phenomenon remained elusive.
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Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
Osteoarthritis (OA) is characterized by articular cartilage degeneration, leading to pain and loss of joint function. Recent studies have demonstrated that omega-3 (ω3) polyunsaturated fatty acid (PUFA) supplementation can decrease injury-induced OA progression in mice fed a high-fat diet. Furthermore, PUFAs have been shown to influence the mechanical properties of chondrocyte membranes, suggesting that alterations in mechanosensitive ion channel signaling could contribute to the mechanism by which ω3 PUFAs decreased OA pathogenesis.
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