Block regional off-resonance correction (BRORC): a fast and effective deblurring method for spiral imaging.

One primary disadvantage of spiral imaging is blurring artifact due to off-resonance effects. The conventional frequency segmented off-resonance correction method that is performed over the entire image is computationally intense due to the large number of fast Fourier transforms (FFTs) required. Here, a new fast off-resonance correction method, block regional off-resonance correction (BRORC), is presented. In this method, off-resonance correction proceeds block-by-block through the reconstructed image with FFTs performed on matrices that are smaller than the full image matrix. The BRORC algorithm is typically several times more computationally efficient than the conventional off-resonance correction algorithm. Additional computational reductions can be expected for the BRORC if only specific image regions require deblurring. The newly proposed off-resonance correction method offers significant speed advantages and equivalent image quality when compared to conventional off-resonance correction methods.