Enhanced quantitative susceptibility mapping (QSM) using real‐time field control. Issue 2 (28th May 2017)

• Record Type: Journal Article
• Authors: Özbay, Pinar Senay; Duerst, Yolanda; Wilm, Bertram Jakob; Pruessmann, Klaas Paul; Nanz, Daniel
• Is Part Of: Magnetic resonance in medicine. Volume 79:Issue 2(2018)
• Page Start: 770
• Page End: 778
• Publication Date: 2017-05-28
• Subjects: quantitative susceptibility mapping (QSM) -- phase -- gradient echo -- NMR field probes -- field control -- 7 T; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.26735
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To assess the potential of a real‐time field‐control (FC) system for mitigating effects of spatiotemporal field fluctuations in quantitative susceptibility mapping (QSM) at 7 T. Methods: Magnitude, phase, and QSM images of phantoms and healthy volunteers were acquired under standard conditions and under induced field perturbation (FP) (phantoms: periodic water‐bottle displacement; volunteers: deep breathing and forearm movement) with and without FC, which continuously detects and minimizes magnetic‐field variations. Results: Field control successfully eliminated FP‐induced impairment of phantom image quality and deviations from a linear susceptibility increase for increasing gadolinium concentration in a Gd dilution series (y = 320x – 0.60, R 2 = 0.93 for the scan with FP and FC versus y = 259x – 0.54, R 2 = 0.78 for the scan with FP and no FC (slope literature value: 326 ppm L/mol)). Similarly, in volunteers, FC allowed a recovery of a FP‐induced loss of identifiable brain structures and reduced the relative change of mean susceptibilities and standard deviations (93 ± 53% to 34 ± 46%) in all regions of interests with respect to the reference scan. Conclusions: Real‐time FC improved the delineation of brain structures and the match of susceptibility values with reference values obtained without FP. Magn Reson Med 79:770–778, 2018. © 2017 International Society for Magnetic Resonance in Medicine.