Eddy current compensation for delta relaxation enhanced MR by dynamic reference phase modulation.
OBJECTIVE
Eddy current compensation by dynamic reference phase modulation (eDREAM) is a compensation method for eddy current fields induced by B 0 field-cycling which occur in delta relaxation enhanced MR (dreMR) imaging. The presented method is based on a dynamic frequency adjustment and prevents eddy current related artifacts. It is easy to implement and can be completely realized in software for any imaging sequence.


METHODS
In this paper, the theory of eDREAM is derived and two applications are demonstrated. The theory describes how to model the behavior of the eddy currents and how to implement the compensation. Phantom and in vivo measurements are carried out and demonstrate the benefits of eDREAM.


RESULTS
A comparison of images acquired with and without eDREAM shows a significant improvement in dreMR image quality. Images without eDREAM suffer from severe artifacts and do not allow proper interpretation while images with eDREAM are artifact free. In vivo experiments demonstrate that dreMR imaging without eDREAM is not feasible as artifacts completely change the image contrast.


CONCLUSIONS
eDREAM is a flexible eddy current compensation for dreMR. It is capable of completely removing the influence of eddy currents such that the dreMR images do not suffer from artifacts.
Research Center for Magnetic Resonance Bavaria (MRB), Würzburg, Germany. hoelscher@mr-bavaria.de
Uvo Christoph
UC
Hoelscher
Peter M
PM
Jakob
D000818:Animals; D016477:Artifacts; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D060328:Magnetic Phenomena; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data; D051379:Mice; D008819:Mice, Nude; D008962:Models, Theoretical; D009374:Neoplasms, Experimental / Q000473:pathology; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio