Application of k-space energy spectrum analysis for inherent and dynamic B0 mapping and deblurring in spiral imaging

✍ Scribed by Trong-Kha Truong; Nan-kuei Chen; Allen W. Song

• Book ID: 102955503
• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 941 KB
• Volume: 64
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.22485

✦ Synopsis

Abstract

Spiral imaging is vulnerable to spatial and temporal variations of the amplitude of the static magnetic field (B~0~) caused by susceptibility effects, eddy currents, chemical shifts, subject motion, physiological noise, and system instabilities, resulting in image blurring. Here, a novel off‐resonance correction method is proposed to address these issues. A k‐space energy spectrum analysis algorithm is first applied to inherently and dynamically generate a B~0~ map from the k‐space data at each time point, without requiring any additional data acquisition, pulse sequence modification, or phase unwrapping. A simulated phase evolution rewinding algorithm and an automatic residual deblurring algorithm are then used to correct for the blurring caused by both spatial and temporal B~0~ variations, resulting in a high spatial and temporal fidelity. This method is validated against conventional B~0~ mapping and deblurring methods, and its advantages for dynamic MRI applications are demonstrated in functional MRI studies. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.