Two‐dimensional single‐shot diffusion‐weighted stimulated EPI with reduced FOV for ultrahigh‐b radial diffusion‐weighted imaging of spinal cord. Issue 6 (14th June 2016)

• Record Type: Journal Article
• Authors: Sapkota, Nabraj; Shi, Xianfeng; Shah, Lubdha M.; Bisson, Erica F.; Rose, John W.; Jeong, Eun‐Kee
• Is Part Of: Magnetic resonance in medicine. Volume 77:Issue 6(2017)
• Page Start: 2167
• Page End: 2173
• Publication Date: 2016-06-14
• Subjects: ultrahigh‐b -- spinal cord -- diffusion‐weighted imaging -- stimulated echo -- reduced FOV; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.26302
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: High‐resolution diffusion‐weighted imaging (DWI) of the spinal cord (SC) is problematic because of the small cross‐section of the SC and the large field inhomogeneity. Obtaining the ultrahigh‐b DWI poses a further challenge. The purpose of the study was to design and validate two‐dimensional (2D) single‐shot diffusion‐weighted stimulated echo planar imaging with reduced field of view (2D ss‐DWSTEPI‐rFOV) for ultrahigh‐b radial DWI (UHB‐rDWI) of the SC. Methods: A novel time‐efficient 2D ss‐DWSTEPI‐rFOV sequence was developed based on the stimulated echo sequence. Reduced‐phase field of view was obtained by using two slice‐selective 90 ° radiofrequency pulses in the presence of the orthogonal slice selection gradients. The sequence was validated on a cylindrical phantom and demonstrated on SC imaging. Results: Ultrahigh‐b radial diffusion‐weighted ( b m a x = 7300 s / m m 2 ) images of the SC with greatly reduced distortion were obtained. The exponential plus constant fitting of the diffusion‐decay curve estimated the constant fraction (restricted water fraction) as 0.36 ± 0.05 in the SC white matter. Conclusion: A novel 2D ss‐DWSTEPI‐rFOV sequence has been designed and demonstrated for high‐resolution UHB‐rDWI of localized anatomic structures with significantly reduced distortion induced by nonlinear static field inhomogeneity. Magn Reson Med 77:2167–2173, 2017. © 2016 International Society for Magnetic Resonance in Medicine