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Multi-Directional Phase-Contrast Flow MRI in Real Time

dc.contributor.advisorFrahm, Jens Prof. Dr.
dc.contributor.authorKollmeier, Jost M.
dc.date.accessioned2021-01-28T08:24:12Z
dc.date.available2021-01-28T08:24:12Z
dc.date.issued2021-01-28
dc.identifier.urihttp://hdl.handle.net/21.11130/00-1735-0000-0005-155C-D
dc.identifier.urihttp://dx.doi.org/10.53846/goediss-8413
dc.language.isoengde
dc.relation.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc571.4de
dc.titleMulti-Directional Phase-Contrast Flow MRI in Real Timede
dc.typedoctoralThesisde
dc.contributor.refereeFrahm, Jens Prof. Dr.
dc.date.examination2020-08-31
dc.description.abstractengThis work describes the development of a phase-contrast MRI technique that achieves multi-directional velocity quantification in real time, i.e. at high spatio-temporal resolution and without any physiological gating or data sorting. The technique exploits highly undersampled radial acquisitions with time-efficient flow encoding, a correction strategy for concomitant fields applicable to radial imaging, and an iterative solution for the non-linear image reconstruction problem. MRI is a potent and versatile imaging technique that allows to measure flow velocities, e.g. of blood flow. Unfortunately, MRI is intrinsically slow. Recent advances in real-time MRI based on radial FLASH and non-linear inversion offer high spatio-temporal resolutions and the realization of cross-sectional MRI movies. This real-time approach had been combined with uni-directional phase-contrast flow MRI that quantifies velocities only perpendicular to the imaging plane. In this work, the imaging technique is extended to more velocity dimensions. Opening with a brief overview on the basic principles of phase-contrast and real-time MRI (Chapter 2), this thesis presents the uni-directional flow technique in Chapter 3 followed by proposals for further improvements. Chapter 4 describes the development of a multi-directional extension and its optimization towards high spatio-temporal resolutions, while Chapter 5 proposes further methodological refinements. Chapter 6 addresses the technical accuracy and presents a correction strategy to eliminate background phase errors by concomitant magnetic fields applicable to radial imaging. Preliminary in vivo results demonstrated in Chapter 7 include cardiac flow imaging with velocity quantification in all three directions at less than 2 x 2 mm² pixel-size and more than 60 frames per second. The novel MRI technique developed in this thesis increases the potential of MRI based cross-sectional velocimetry.de
dc.contributor.coRefereeEnderlein, Jörg Prof. Dr.
dc.contributor.thirdRefereeScheffler, Klaus Prof. Dr.
dc.subject.engreal-time MRIde
dc.subject.engphase-contrast MRIde
dc.subject.engradial MRIde
dc.subject.engmodel-based reconstructionde
dc.subject.engradial Maxwell correctionde
dc.subject.engmulti-directional flowde
dc.subject.eng4D flowde
dc.subject.engvelocimetryde
dc.subject.engKarman vortex sheddingde
dc.subject.engblood flowde
dc.subject.engCSF flowde
dc.subject.eng3D flowde
dc.identifier.urnurn:nbn:de:gbv:7-21.11130/00-1735-0000-0005-155C-D-7
dc.affiliation.instituteGöttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB)de
dc.subject.gokfullBiologie (PPN619462639)de
dc.identifier.ppn1745980636


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