M1-optimized Liver DWI using Tetrahedral Diffusion Gradients on Conventional Gradient Systems

M1-optimized diffusion gradient waveforms allow for motion-robust liver DWI and ADC estimation. However, existing implementations have been limited to 3.0T scanners with high-performance gradient systems. This work introduces M1-optimized waveforms using a tetrahedral diffusion encoding to allow for high quality, motion-robust DWI on a 1.5T system with conventional gradient performance. Additionally, it addresses complications of this approach, namely increased concomitant gradients and eddy currents. Phantom experiments demonstrate a reduction in geometric distortion and bias of ADC maps generated with this approach compared to Stejskal–Tanner (monopolar) and non-tetrahedral gradient designs. Human subject imaging demonstrates increased motion-robustness.