Concurrent Field Monitoring Removes Distortions from In-Vivo DWI Data

Bertram Jakob Wilm¹, Christoph Barmet², Nicola DeZanche², Peter Boesiger², Klaas Paul Pruessmann²

In diffusion-weighted MRI, eddy current effects notoriously result in geometrical image distortions. This problem is usually approached by fine-calibration of the scanner gradient system. We present a generic way of addressing this problem by deliberately tolerating a certain degree of field deviations in terms of eddy currents, gradient delays and field drifts and rather monitor the actual magnetic field during each scan. The field evolution thereby obtained is used for distortion correction of in-vivo DWI data that was acquired in the absence of hardware eddy current compensation.