Utility of real-time field control in T<sub>2</sub>
*-Weighted head MRI at 7T

Duerst, Yolanda; Wilm, Bertram J.; Wyss, Michael; Dietrich, Benjamin E.; Gross, Simon; Schmid, Thomas; Brunner, David O.; Pruessmann, Klaas P.

doi:10.1002/mrm.25838

Cited by 33 publications

(58 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The navigator echo‐based approach used in this study can increase the total scan time, perturb signal steady‐states, or not capture field dynamics . There are various ways of removing respiratory motion effects . A correction method utilizing retrospective gating is widely used for both respiratory and cardiac motion correction in fMRI studies using an EPI sequence .…”

Section: Discussionmentioning

confidence: 99%

Improvement of reproducibility in quantitative susceptibility mapping (QSM) and transverse relaxation rates () after physiological noise correction

Choi

Lee

Nam

et al. 2018

Magnetic Resonance Imaging

View full text Add to dashboard Cite

Background Numerous studies have suggested that quantitative susceptibility mapping (QSM) and transverse relaxation rates (normalR2*) are useful to monitor neurological diseases. For clinical use of QSM and normalR2*, reproducibility is an important feature. However, respiration‐induced local magnetic field variation makes artifacts in gradient echo‐based images and reduces the reproducibility of QSM and normalR2*. Purpose To investigate the improvement of reproducibility of QSM and normalR2* after the correction of respiration‐induced field variation, and to assess the effect of varying types of the region of interest (ROI) analysis on reproducibility. Study Type Reproducibility study. Population Ten controls. Field Strength/Sequence 3T/multiecho gradient echo sequence. Assessment Intrascan reproducibility of QSM and normalR2* was investigated in ROIs before and after the respiration correction. Statistical Tests Reproducibility was obtained by the square of voxel‐wise correlation coefficients between scans. A paired t‐test was performed for comparison between before and after the respiration correction and between QSM and normalR2*. Results Based on the ROI analysis, reproducibility increased after the respiration correction. Reproducibility in the white matter (11.89% increased in QSM and 23.38% in normalR2*, P = 0.009 and 0.024, respectively) and deep gray matter (5.50% increased in QSM and 13.96% in normalR2*, P = 0.024 and 0.019, respectively) increased significantly after the respiration correction. Reproducibility of normalR2* was higher than that of QSM in the whole brain and cortical gray matter, while QSM maps showed higher reproducibility than normalR2* in the white matter and deep gray matter. Data Conclusion Respiration‐induced error correction significantly improved reproducibility in QSM and normalR2* mapping. QSM and normalR2* mapping showed a different level of reproducibility depending on the types of ROI analysis. Level of Evidence: 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.

show abstract

Section: Discussionmentioning

confidence: 99%

Improvement of reproducibility in quantitative susceptibility mapping (QSM) and transverse relaxation rates () after physiological noise correction

Choi

Lee

Nam

et al. 2018

Magnetic Resonance Imaging

View full text Add to dashboard Cite

show abstract

“…One potential use of a FC system could be research/clinical studies with elderly people, as these patients commonly suffer from dyspnea (i.e., breathing disorders due to breathlessness, chest tightness, or increased effort of breathing) . In a previous study, FC also eliminated the field fluctuations in

{normalT}_{2}^{*}

‐weighted images of healthy subjects with higher BMI, as a result of movement of more tissue during the breathing cycle . However, in our current study, we included young healthy volunteers without breathing problems, and the differences between reference and “no FP, with FC” QSM images were too small for a direct visual detection (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The field‐probe concept has recently been extended to a feedback implementation for real‐time field compensation up to third order in space . In previous studies, it has been shown to reduce breathing artifacts in

{normalT}_{2}^{*}

‐weighted brain images and

{normalT}_{2}^{*}

maps acquired at 7 T . The purpose of this study was to assess the potential of real‐time field control to enhance gradient echo–based QSM images acquired at 7 T based on phantom and volunteer experiments.…”

Section: Introductionmentioning

confidence: 99%

Enhanced quantitative susceptibility mapping (QSM) using real‐time field control

Özbay

Duerst

Wilm

et al. 2017

Magnetic Resonance in Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…Navigator echoes have been used to directly track the fluctuating signal phase by measuring non‐phase‐encoded echoes interleaved with the actual data acquisition 5,7,8 which increases scan time. Examples for the use of external sensors are the signals generated by respiratory bellows 9 or NMR field probes, which have been used for real‐time compensation of the fluctuating

B_{0}

field 10,11 . The former approach increases the complexity of the examination workflow and is limited by the imperfect correlation of the breathing signal and the actual changes in

B_{0}

.…”

Section: Introductionmentioning

confidence: 99%

Data consistency‐driven determination of ‐fluctuations in gradient‐echo MRI

Meineke

Nielsen

2018

Magnetic Resonance in Med

View full text Add to dashboard Cite

Purpose Introduce a method to estimate B0‐fluctuations based on the analysis of raw k‐space data, without sequence modifications or external hardware, and correct for their detrimental effects in gradient‐echo MRI. Theory Inconsistencies in multi‐channel raw k‐space data can be used to estimate B0‐fluctuations by exploiting coil‐sensitivity information. Methods The proposed method, dubbed consistency navigation, is used to extract B0‐fluctuations from T2*‐weighted 3D gradient‐echo data. These results are compared with the results from an MR phase navigator and respiratory bellows. The spatial variation of the B0‐fluctuation amplitude is derived using the sensitivity maps of the coil array and compared with direct measurements based on dynamic 2D gradient‐echo data. Results B0‐fluctuations derived from the consistency navigator and MR phase navigator are highly correlated. Images corrected for these fluctuations show marked improvements in homogeneity and tissue delineation. The spatial variation of the B0‐fluctuation amplitude follows closely the variation directly measured from time‐resolved 2D scans. Conclusions Based on the consistency navigator, an accurate estimation of the spatiotemporal characteristics of B0‐fluctuations and correction of T2*‐weighted images has been demonstrated.

show abstract

Utility of real-time field control in T₂ *-Weighted head MRI at 7T

Cited by 33 publications

References 35 publications

Improvement of reproducibility in quantitative susceptibility mapping (QSM) and transverse relaxation rates () after physiological noise correction

Improvement of reproducibility in quantitative susceptibility mapping (QSM) and transverse relaxation rates () after physiological noise correction

Enhanced quantitative susceptibility mapping (QSM) using real‐time field control

Data consistency‐driven determination of ‐fluctuations in gradient‐echo MRI

Contact Info

Product

Resources

About

Utility of real-time field control in T2 *-Weighted head MRI at 7T

Cited by 33 publications

References 35 publications

Improvement of reproducibility in quantitative susceptibility mapping (QSM) and transverse relaxation rates () after physiological noise correction

Improvement of reproducibility in quantitative susceptibility mapping (QSM) and transverse relaxation rates () after physiological noise correction

Enhanced quantitative susceptibility mapping (QSM) using real‐time field control

Data consistency‐driven determination of ‐fluctuations in gradient‐echo MRI

Contact Info

Product

Resources

About

Utility of real-time field control in T₂ *-Weighted head MRI at 7T