Keywords: Low-Field MRI, Low-Field MRI, eddy current measurement, field probe
Motivation: Eddy current results in resolution degradation and unwanted phase variations. However, there have been relatively few eddy-current related studies carried out in low field recently.
Goal(s): Our goal was to introduce and compare image-phase based and FID-phase based eddy current measurement techniques in a 64mT MRI system and reduced eddy-current effects.
Approach: We employed a large phantom or six field probes to measure eddy-current-induced gradients shift. And we modeled them as sums of exponentially decaying components to compensate the gradient unit.
Results: Eddy-current-induced field shift was initially about 350ppm, and reduced to 240ppm and 20ppm by these two methods.
Impact: This work develops two methods for measuring eddy current in low-field MRI, especially for portable scanner, which help reducing eddy-current-induced effects and improving the image quality of clinical sequence (e.g. DWI, DTI) in low field scanner.
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