Show simple item record

Multi-Directional Phase-Contrast Flow MRI in Real Time

dc.contributor.advisorFrahm, Jens Prof. Dr.
dc.contributor.authorKollmeier, Jost M.
dc.titleMulti-Directional Phase-Contrast Flow MRI in Real Timede
dc.contributor.refereeFrahm, Jens Prof. Dr.
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
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.engKarman vortex sheddingde
dc.subject.engblood flowde
dc.subject.engCSF flowde
dc.subject.eng3D flowde
dc.affiliation.instituteGöttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB)de
dc.subject.gokfullBiologie (PPN619462639)de

Files in this item


This item appears in the following Collection(s)

Show simple item record