T2-weighted Spine Imaging using a Single-Shot Turbo Spin Echo Pulse Sequence

T2 weighted imaging of the spine is commonly performed using fast spin echo (FSE/TSE) based sequences, resulting in long scan times and vulnerability to motion artifacts. While single shot fast spin echo sequences have been attempted, their adoption has been limited by poor spatial resolution and specific absorption rate (SAR) limitations. We investigate the use of a half-Fourier acquisition single-shot turbo spin-echo variable flip angle (HASTE-VFA) sequence for T2 weighted spine imaging. A variable refocusing flip angle echo train was first optimized for the spine to improve the point spread function (PSF) and minimize SAR, yielding images with improved spatial resolution and signal-to-noise ratio compared to the constant flip angle sequence. Data was acquired from 29 patients (20 lumbar and thoracolumbar, 9 whole-spine) using conventional fast spin echo and the proposed variable flip angle single-shot sequences. All images were graded by two experienced neuroradiologists in a blinded fashion and scores were assigned based on blurring, motion, artifacts, and noise as well as appearance of disks, facet joints, end plates, nerve roots and the spinal cord.
Comment: 13 pages, 7 figures, 4 tables, Previously submitted to "Investigative Radiology"