Dataset Information
Real-time motion and retrospective coil sensitivity correction for CEST using volumetric navigators (vNavs) at 7T.
Ontology highlight
ABSTRACT: Purpose
To explore the impact of temporal motion-induced coil sensitivity changes on CEST-MRI at 7T and its correction using interleaved volumetric EPI navigators, which are applied for real-time motion correction.Methods
Five healthy volunteers were scanned via CEST. A 4-fold correction pipeline allowed the mitigation of (1) motion, (2) motion-induced coil sensitivity variations, ?B1- , (3) motion-induced static magnetic field inhomogeneities, ?B0 , and (4) spatially varying transmit RF field fluctuations, ?B1+ . Four CEST measurements were performed per session. For the first 2, motion correction was turned OFF and then ON in absence of voluntary motion, whereas in the other 2 controlled head rotations were performed. During post-processing ?B1- was removed additionally for the motion-corrected cases, resulting in a total of 6 scenarios to be compared. In all cases, retrospective ?B0 and - ?B1+ corrections were performed to compute artifact-free magnetization transfer ratio maps with asymmetric analysis (MTRasym ).Results
Dynamic ?B1- correction successfully mitigated signal deviations caused by head motion. In 2 frontal lobe regions of volunteer 4, induced relative signal errors of 10.9% and 3.9% were reduced to 1.1% and 1.0% after correction. In the right frontal lobe, the motion-corrected MTRasym contrast deviated 0.92%, 1.21%, and 2.97% relative to the static case for ?? = 1, 2, 3 ± 0.25 ppm. The additional application of ?B1- correction reduced these deviations to 0.10%, 0.14%, and 0.42%. The fully corrected MTRasym values were highly consistent between measurements with and without intended head rotations.Conclusion
Temporal ?B1- cause significant CEST quantification bias. The presented correction pipeline including the proposed retrospective ?B1- correction significantly reduced motion-related artifacts on CEST-MRI.
SUBMITTER: Poblador Rodriguez E
PROVIDER: S-EPMC7839562 | biostudies-literature | 2021 Apr
REPOSITORIES: biostudies-literature
Publications
Real-time motion and retrospective coil sensitivity correction for CEST using volumetric navigators (vNavs) at 7T.
Magnetic resonance in medicine 20201109 4
<h4>Purpose</h4>To explore the impact of temporal motion-induced coil sensitivity changes on CEST-MRI at 7T and its correction using interleaved volumetric EPI navigators, which are applied for real-time motion correction.<h4>Methods</h4>Five healthy volunteers were scanned via CEST. A 4-fold correction pipeline allowed the mitigation of (1) motion, (2) motion-induced coil sensitivity variations, ΔB1- , (3) motion-induced static magnetic field inhomogeneities, ΔB<sub>0</sub> , and (4) spatially ...[more]