VPAL: A novel method to reduce reconstruction time for 5D free-running imaging

Area of Science:

• Medical Imaging
• Cardiovascular MRI
• Image Reconstruction

Background:

• Ferumoxytal-enhanced 5D free-running whole heart CMR offers image quality comparable to CTA.
• Current reconstruction times are hours-long, hindering clinical application.

Purpose of the Study:

• Develop a Variable Projection Augmented Lagrangian (VPAL) method for accelerated 5D motion-resolved image reconstruction.
• Compare VPAL with the Alternating Direction Method of Multipliers (ADMM) for speed and image quality.

Main Methods:

• Evaluated VPAL and ADMM using five numerical simulations and 15 pediatric in-vivo datasets.
• Assessed relative error against ground truth in simulations.
• Compared reconstruction time, blood-myocardium sharpness, LVEF, and radiologist ratings in vivo.

Main Results:

• VPAL and ADMM showed comparable relative errors (p=0.07).
• VPAL drastically reduced reconstruction time (4.7 ± 1.1 hours) compared to ADMM (16.3 ± 3.6 hours, p=1e-10).
• VPAL maintained excellent blood-myocardium sharpness (R²=0.97) and similar LVEF measurements (p=0.55) with good to excellent diagnostic ratings.

Conclusions:

• VPAL significantly accelerates 5D cardiac MRI reconstruction.
• The method preserves diagnostic image quality for functional assessments.
• VPAL shows strong potential for clinical translation of accelerated cardiac MRI.