Marcus T. Alley1, Mark J. Murphy2, Kurt Keutzer2, Michael Lustig2, Shreyas S. Vasanawala1
1Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering & Computer Science, University of California, Berkeley, CA, United States
Time-resolved 3-dimensional phase-contrast MR imaging (4D-PC MRI) has become more clinically viable with the advent of parallel imaging. However, undersampling patterns suitable for GRAPPA-like reconstructions often result in coherent artifacts in the final images. Here we demonstrate the use of variable density Poisson-disc/ellipse pseudorandom sampling in conjunction with the L1-SPIRiT compressed sensing reconstruction implemented on general-purpose graphics processors (GPGPU). The combined approach provides improved image quality, better artifact reduction in clinically viable acquisition and reconstruction times. In addition, we have implemented a partial respiratory triggering approach to reduce breathing artifacts with a minimal increase in scan-time.