PURPOSE: Diffusion MRI is compromised by unknown field perturbation during image encoding. The purpose of this study was to address this problem using the recently described approach of concurrent magnetic field monitoring. METHODS: Magnetic field dynamics were monitored during the echo planar imaging readout of a common diffusion-weighted MRI sequence using an integrated magnetic field camera setup. The image encoding including encoding changes over the duration of entire scans were quantified and analyzed. Field perturbations were corrected by accounting for them in generalized image reconstruction. The impact on image quality along with geometrical congruence among different diffusion-weighted images was assessed both qualitatively and quantitatively. RESULTS: The most significant field perturbations were found to be related to higher-order eddy currents from diffusion-weighting gradients and B0 field drift as well as gradual changes of short-term eddy current behavior and mechanical oscillations during the scan. All artifacts relating to dynamic field perturbations were eliminated by incorporating the measured encoding in image reconstruction. CONCLUSION: Concurrent field monitoring combined with generalized reconstruction enhances depiction fidelity in diffusion imaging. In addition to artifact reduction, it improves geometric congruence and thus facilitates image combination for quantitative diffusion analysis.
PURPOSE: Diffusion MRI is compromised by unknown field perturbation during image encoding. The purpose of this study was to address this problem using the recently described approach of concurrent magnetic field monitoring. METHODS: Magnetic field dynamics were monitored during the echo planar imaging readout of a common diffusion-weighted MRI sequence using an integrated magnetic field camera setup. The image encoding including encoding changes over the duration of entire scans were quantified and analyzed. Field perturbations were corrected by accounting for them in generalized image reconstruction. The impact on image quality along with geometrical congruence among different diffusion-weighted images was assessed both qualitatively and quantitatively. RESULTS: The most significant field perturbations were found to be related to higher-order eddy currents from diffusion-weighting gradients and B0 field drift as well as gradual changes of short-term eddy current behavior and mechanical oscillations during the scan. All artifacts relating to dynamic field perturbations were eliminated by incorporating the measured encoding in image reconstruction. CONCLUSION: Concurrent field monitoring combined with generalized reconstruction enhances depiction fidelity in diffusion imaging. In addition to artifact reduction, it improves geometric congruence and thus facilitates image combination for quantitative diffusion analysis.
Authors: Susie Y Huang; Thomas Witzel; Boris Keil; Alina Scholz; Mathias Davids; Peter Dietz; Elmar Rummert; Rebecca Ramb; John E Kirsch; Anastasia Yendiki; Qiuyun Fan; Qiyuan Tian; Gabriel Ramos-Llordén; Hong-Hsi Lee; Aapo Nummenmaa; Berkin Bilgic; Kawin Setsompop; Fuyixue Wang; Alexandru V Avram; Michal Komlosh; Dan Benjamini; Kulam Najmudeen Magdoom; Sudhir Pathak; Walter Schneider; Dmitry S Novikov; Els Fieremans; Slimane Tounekti; Choukri Mekkaoui; Jean Augustinack; Daniel Berger; Alexander Shapson-Coe; Jeff Lichtman; Peter J Basser; Lawrence L Wald; Bruce R Rosen Journal: Neuroimage Date: 2021-08-28 Impact factor: 7.400
Authors: Qiuyun Fan; Cornelius Eichner; Maryam Afzali; Lars Mueller; Chantal M W Tax; Mathias Davids; Mirsad Mahmutovic; Boris Keil; Berkin Bilgic; Kawin Setsompop; Hong-Hsi Lee; Qiyuan Tian; Chiara Maffei; Gabriel Ramos-Llordén; Aapo Nummenmaa; Thomas Witzel; Anastasia Yendiki; Yi-Qiao Song; Chu-Chung Huang; Ching-Po Lin; Nikolaus Weiskopf; Alfred Anwander; Derek K Jones; Bruce R Rosen; Lawrence L Wald; Susie Y Huang Journal: Neuroimage Date: 2022-02-23 Impact factor: 7.400
Authors: Yoojin Lee; Adam O Kettinger; Bertram Jakob Wilm; Ralf Deichmann; Nikolaus Weiskopf; Christian Lambert; Klaas Paul Pruessmann; Zoltan Nagy Journal: Magn Reson Med Date: 2019-12-16 Impact factor: 4.668