Spiral imaging is a fast MRI technique that is widely used in functional MRI. It is, however, vulnerable to spatial and temporal variations of the static magnetic field (B0) caused by susceptibility effects, subject motion, physiological noise, and system instabilities, resulting in blurring artifacts. To address these issues, we have developed a novel off-resonance correction method, based on k-space energy spectrum analysis (KESA), for inherent and dynamic B0 mapping and deblurring in spiral imaging. This method can generate a B0 map from the k-space data at each time point, without requiring any additional data acquisition or pulse sequence modification, and correct for the blurring caused by both spatial and temporal B0 variations, resulting in a high spatial and temporal fidelity.
Citation: Truong TK, Chen NK, Song AW. Application of k-space energy spectrum analysis for inherent and dynamic B0 mapping and deblurring in spiral imaging. Magn Reson Med. 2010 Oct;64(4):1121-7. doi: 10.1002/mrm.22485. PMID: 20564589; PMCID: PMC2945618.