ABSTRACTBACKGROUND AND PURPOSEThe combination of phase demodulation and field mapping is a practical method to correct echo planar imaging (EPI) geometric distortion. However, since phase dispersion accumulates in each phase‐encoding step, the calculation complexity of phase modulation is Ny‐fold higher than conventional image reconstructions. Thus, correcting EPI images via phase demodulation is generally a time‐consuming task.METHODSParallel computing by employing general‐purpose calculations on graphics processing units (GPU) can accelerate scientific computing if the algorithm is parallelized. This study proposes a method that incorporates the GPU‐based technique into phase demodulation calculations to reduce computation time. The proposed parallel algorithm was applied to a PROPELLER‐EPI diffusion tensor data set.RESULTSThe GPU‐based phase demodulation method reduced the EPI distortion correctly, and accelerated the computation. The total reconstruction time of the 16‐slice PROPELLER‐EPI diffusion tensor images with matrix size of 128 × 128 was reduced from 1,754 seconds to 101 seconds by utilizing the parallelized 4‐GPU program.CONCLUSIONSGPU computing is a promising method to accelerate EPI geometric correction. The resulting reduction in computation time of phase demodulation should accelerate postprocessing for studies performed with EPI, and should effectuate the PROPELLER‐EPI technique for clinical practice.