Kazim Gumus1, Benedikt Poser1, Brian Keating1, Brian Armstrong2, Julian Maclaren3, Thomas Prieto4, Oliver Speck5, Maxim Zaitsev6, Thomas Ernst1
1John A. Burns School of Medicine, U. of Hawaii, Honolulu, HI, United States; 2Dept. of Electrical Engineering and Computer, U. of Wisconsin-Milwaukee, Milwaukee, WI, United States; 3Dept. of Radiology, University Medical Center Freiburg, Freiburg, Germany; 4Neurology, Medical College of Wisconsin, Wauwatosa, WI, United States; 5Dept. Biomedical Magnetic Resonance, Otto-von-Guericke-University, Magdeburg, Germany; 6Dept. of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany
Intra-scan head motion causes signal dropouts in DWI. A new method is presented to eliminate such artifacts. We used a Moir-Phase-Target based tracking system to measure head motion between excitation and acquisition. Knowing also the timing and amplitudes of gradients, we determined the motion-induced residual gradient moment (M) and restored the gradient balance prior to readout by applying a blip gradient of moment -M. The method was tested on two volunteers who performed intentional head movements. Gradient moment correction successfully eliminated signal dropouts compared to scans without correction. This method should be feasible on most modern scanner platforms.