Two-dimensional single-shot diffusion-weighted stimulated EPI with reduced FOV for ultrahigh-b radial diffusion-weighted imaging of spinal cord.
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.



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.



Ultrahigh-b radial diffusion-weighted ( bmax = 7300 s/mm2) 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.



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.
Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.|Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah, USA.
Nabraj
N
Sapkota
Department of Psychiatry, University of Utah, Salt Lake City, Utah, USA.
Xianfeng
X
Shi
Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA.
Lubdha M
LM
Shah
Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA.
Erica F
EF
Bisson
Department of Neurology, University of Utah, Salt Lake City, Utah, USA.
John W
JW
Rose
Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.|Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA.
Eun-Kee
EK
Jeong
D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*
diffusion-weighted imaging; reduced FOV; spinal cord; stimulated echo; ultrahigh-b