T₂ shuffling: Sharp, multicontrast, volumetric fast spin-echo imaging.

Area of Science:

• Magnetic Resonance Imaging
• Medical Imaging Physics

Background:

• Volumetric fast spin-echo (3D FSE) imaging is crucial for detailed anatomical visualization.
• Image blurring and limited T2 contrast variability can hinder diagnostic accuracy in 3D FSE.
• Current scan times may not always be clinically feasible for comprehensive multi-contrast imaging.

Purpose of the Study:

• To introduce T2 Shuffling, a novel acquisition and reconstruction method for 3D FSE imaging.
• To reduce blurring and acquire multiple T2 contrasts from a single 3D FSE scan.
• To achieve clinically feasible scan times (6-7 minutes) for enhanced imaging.

Main Methods:

• Modified parallel imaging forward model to incorporate temporal signal relaxation.
• Acquired data during transient signal decay and increased echo train lengths for improved scan efficiency.
• Employed random phase encode view ordering, low-dimensional subspace constraints, and locally low rank regularization to recover virtual echo time images.
• Utilized a convex formulation robust to partial voluming and RF inhomogeneity.

Main Results:

• T2 Shuffling demonstrated increased image sharpness in retrospective undersampling and in vivo scans.
• Multiple image contrasts were successfully recovered from a single acquisition.
• The method highlighted pathology in pediatric patients and was integrated into a clinical musculoskeletal imaging workflow.

Conclusions:

• T2 Shuffling significantly enhances the diagnostic utility of 3D FSE imaging.
• The method effectively reduces blurring and generates multiple contrasts in a single scan.
• This technique offers a more efficient and informative approach to volumetric MRI acquisition.