Spiral HASTE using variable-flip-angle single-shot spiral-ring TSE for rapid T2-weighted abdominal imaging

Motivation: Conventional Cartesian HASTE may be susceptible to image blurring, resolution loss, and artifacts in abdominal imaging. Goal(s): To develop a 2D T2-weighted abdominal spiral HASTE technique to achieve better image sharpness, reduced scan time, and reduced power deposition compared to Cartesian HASTE. Approach: A variable-flip-angle refocusing RF series was designed and employed to maintain high signal-intensity at middle- and late-echoes with a smooth signal-evolution compared to a constant-flip-angle scheme. Variable-density spiral-ring trajectories combined with L1-ESPIRiT reconstruction were performed to accelerate the data acquisition. Results: Whole-abdomen spiral HASTE images were acquired with 1.5×1.5×6 mm3 spatial-resolution and 25 slices in a 7-second acquisition at 3T. Impact: This work highlights the utilization of spiral-ring TSE acquisition along with variable-flip-angle RF pulses and L1-ESPIRiT reconstruction for accelerated single-shot abdominal imaging, providing images with improved image sharpness, shorter scan time, and reduced power deposition over conventional Cartesian HASTE.