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Numerical modeling of susceptibility‐related MR signal dephasing with vessel size measurement: Phantom validation at 3T
Author(s) -
Pannetier Nicolas A.,
Sohlin Maja,
Christen Thomas,
Schad Lothar,
Schuff Norbert
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24968
Subject(s) - dephasing , imaging phantom , signal (programming language) , nuclear magnetic resonance , biomedical engineering , physics , nuclear medicine , computer science , medicine , condensed matter physics , programming language
Purpose MRI is used to obtain quantitative oxygenation and blood volume information from the susceptibility‐related MR signal dephasing induced by blood vessels. However, analytical models that fit the MR signal are usually not accurate over the range of small blood vessels. Moreover, recent studies have demonstrated limitations in the simultaneous assessment of oxygenation and blood volume. In this study, a multiparametric MRI framework that aims to measure vessel radii in addition to magnetic susceptibility and volume fraction was introduced. Methods The protocol consisted of gradient‐echo sampling of the spin‐echo, diffusion, T2, and B0 acquisitions. After correction steps, the data were postprocessed with a versatile numerical model of the MR signal. An important analytical model was implemented for comparison. The approach was validated in phantoms with coiling strings as proxy for blood vessels. Results The feasibility of the vessel radius measurement is demonstrated. The numerical model shows an improved accuracy compared with the analytical approach. However, both methods overestimate the radius. The simultaneous measurement of the magnetic susceptibility and the volume fraction remains challenging. Conclusion The results suggest that this approach could be interesting in vivo to better characterize the microvasculature without contrast agent. Magn Reson Med 72:646–658, 2014. © 2013 Wiley Periodicals, Inc.