title: On the Simultaneous Quantification of Flow Velocities and Relaxation Constants Through Magnetic Resonance Fingerprinting
creator: Flassbeck, Sebastian
subject: 500
subject: 500 Natural sciences and mathematics
subject: 530
subject: 530 Physics
subject: 600
subject: 600 Technology (Applied sciences)
description: In this thesis, the development of a novel magnetic resonance imaging (MRI) pulse sequence  based on magnetic resonance fingerprinting (MRF) is presented. The proposed technique,  termed “Flow-MRF”, allows time-resolved velocities and relaxation constants to be quantified  simultaneously, in shorter acquisition times than conventional MR-based velocimetry.  The simultaneous quantification of both sets of parameters was achieved by formulating the  combined problem in the MRF framework. An MRF pattern was designed to create minimal  coupling between the relaxometric and velocimetric parameter encoding.  Flow-MRF was validated and tested in simulations, phantom experiments, and an in vivo  study targeting the popliteal artery and the gastrocnemius muscle. In each investigation,  Flow-MRF quantified relaxation constants and flow velocities in strong agreement with literature  and reference measurements. Furthermore, the use of high velocity encoding moments  (Δm1 = 60 mT/m·ms^2) was demonstrated while maintaining a range of correctly quantifiable  velocities beyond 800 cm/s. In the volunteer study, Flow-MRF determined an average  longitudinal relaxation time of (1384±75) ms and a transverse relaxation time of (26±4) ms  in the gastrocnemius muscle. The average velocity deviation over all three volunteers between  Flow-MRF and the reference was (-2.6±5.2) cm/s. Lastly, the potential to quantify the complete  Reynolds stress tensor with Flow-MRF was investigated and shown in a stenotic flow  phantom experiment.  Flow‐MRF presents a novel method of quantifying velocities in up to fourfold shorter measurement  times than conventional velocity mapping techniques, while simultaneously providing  relaxometric maps of static tissue. These improvements can potentially be helpful in the  assessment of pathologies such as arteriosclerosis.
date: 2019
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/26414/1/dkfz%20-%20Diss%20--%20Flassbeck%2C%20S%20-%202019%20-%20On%20the%20Simultaneous%20Quantification%20of%20Flow%20Velocities%20and%20Relaxation%20Constants%20Through%20Magnetic%20Resonance%20Fingerprinting.pdf
identifier: DOI:10.11588/heidok.00026414
identifier: urn:nbn:de:bsz:16-heidok-264143
identifier:   Flassbeck, Sebastian  (2019) On the Simultaneous Quantification of Flow Velocities and Relaxation Constants Through Magnetic Resonance Fingerprinting.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/26414/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng