TY  - JOUR
AU  - Schmidt, Simon
AU  - Bruschewski, Martin
AU  - Flassbeck, Sebastian
AU  - John, Kristine
AU  - Grundmann, Sven
AU  - Ladd, Mark E
AU  - Schmitter, Sebastian
TI  - Phase-contrast acceleration mapping with synchronized encoding.
JO  - Magnetic resonance in medicine
VL  - 86
IS  - 6
SN  - 1522-2594
CY  - New York, NY [u.a.]
PB  - Wiley-Liss
M1  - DKFZ-2021-01704
SP  - 3201-3210
PY  - 2021
N1  - #EA:E020#LA:E020# /2021 Dec;86(6):3201-3210
AB  - To develop a phase-contrast (PC) -based method for direct and unbiased quantification of the acceleration vector field by synchronization of the spatial and acceleration encoding time points. The proposed method explicitly aims at in-vitro applications, requiring high measurement accuracy, as well as the validation of clinically relevant acceleration-encoded sequences.A velocity-encoded sequence with synchronized encoding (SYNC SPI) was modified to allow direct acceleration mapping by replacing the bipolar encoding gradients with tripolar gradient waveforms. The proposed method was validated in two in-vitro flow cases: a rotation and a stenosis phantom. The thereby obtained velocity and acceleration vector fields were quantitatively compared to those acquired with conventional PC methods, as well as to theoretical data.The rotation phantom study revealed a systematic bias of the conventional PC acceleration mapping method that resulted in an average pixel-wise relative angle between the measured and theoretical vector field of (7.8 ± 3.2)°, which was reduced to (-0.4 ± 2.7)° for the proposed SYNC SPI method. Furthermore, flow features in the stenosis phantom were displaced by up to 10 mm in the conventional PC data compared with the acceleration-encoded SYNC SPI data.This work successfully demonstrates a highly accurate method for direct acceleration mapping. It thus complements the existing velocity-encoded SYNC SPI method to enable the direct and unbiased quantification of both the velocity and acceleration vector field for in vitro studies. Hence, this method can be used for the validation of conventional acceleration-encoded PC methods applicable in-vivo.
KW  - acceleration mapping (Other)
KW  - displacement artifact (Other)
KW  - flow MRI (Other)
KW  - phase-contrast magnetic resonance imaging (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:34313340
DO  - DOI:10.1002/mrm.28948
UR  - https://inrepo02.dkfz.de/record/170010
ER  -