guest ::
TY - THES AU - Chen, Qingping TI - Development and implementation of accelerated multiple-quantum-filtered sodium magnetic resonance imaging using compressed sensing at ultra-high field PB - Rheinisch-Westfälische Technische Hochschule Aachen VL - Dissertation CY - Aachen M1 - RWTH-2025-03519 SP - 1 Online-Ressource : Illustrationen PY - 2025 N1 - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University N1 - Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2025 AB - Sodium (23Na) plays a critical role in cellular metabolic processes via the regulation of the sodium-potassium pump, which maintains a large gradient between intracellular and extracellular sodium concentrations at the expense of energy. Cellular dysfunction can lead to an elevated intracellular sodium concentration, whereas the extracellular sodium concentration remains primarily unchanged due to tissue perfusion. Therefore, intracellular sodium, as a direct link to cell integrity and tissue viability, promises means for an insight into pathological processes.Conventional sodium Magnetic Resonance Imaging (MRI) with a single radiofrequency pulse can only detect total sodium. Based on the quadrupolar nature of the sodium nucleus, an advanced technique, Multiple-Quantum-Filtered (MQF) sodium MRI, is proposed to monitor restricted (mainly intracellular) sodium. However, the clinical application of MQF sodium MRI is hampered by the relatively low image quality and associated long acquisition times. This thesis aims to mitigate the limitations of MQF sodium MRI by exploiting two aspects: data acquisition and image reconstruction. Regarding data acquisition, this thesis optimised the enhanced Simultaneous Single-quantum and Triple-quantum-filtered imaging of 23NA (SISTINA) sequence using a highly efficient non-Cartesian sampling scheme. Qualitative validation of this sequence optimisation was conducted by comparing the optimised sequence with a conventional enhanced SISTINA sequence in phantom measurements at 7T. The optimisation greatly improved the visual performance of ultra-short-echo-time images, while maintaining the visual quality of MQF images and introducing incoherence in raw data for the application of Compressed Sensing (CS) acceleration. Regarding image reconstruction, this thesis applied CS to accelerate enhanced SISTINA acquisitions by exploiting image sparsity to compensate for incoherent under sampling artefacts. Quantitative validation of the CS acceleration was performed by comparing the under sampled CS-based reconstructions with fully sampled and under sampled standard Non-Uniform Fast Fourier Transform (NUFFT) reconstructions in both phantom and in vivo measurements at 7T. Compared to NUFFT, CS accelerated enhanced SISTINA by up to twofold at 7T in this study with reduced noise levels, while maintaining primary structural information, reasonable weightings towards total and compartmental sodium and relatively accurate in vivo quantification. LB - PUB:(DE-HGF)11 DO - DOI:10.18154/RWTH-2025-03519 UR - https://publications.rwth-aachen.de/record/1009543 ER -