Fast, variable system delay correction for spiral MRI

Purpose Time-varying system delays and eddy currents can substantially reduce the image quality of spiral images. A new method is proposed to estimate variable system delays for spiral-based trajectories. Methods This approach requires a minor modification of a conventional stack-of-spirals sequence and analyzes data collected on three overlapping orthogonal cylinders. Results Initial results are presented for acquired and synthesized phantom data and in vivo data. Conclusion The proposed method includes gradient coupling effects, requires no phantom measurements or specialized hardware, is robust to off-resonance effects, and estimates independent continuous delays for each gradient channel over the data-sampling period. Magn Reson Med 71:773–782, 2014. © 2013 Wiley Periodicals, Inc.