3D Whole-Heart Joint T₁/T_1ρ Mapping and Water-Fat Imaging on a Clinical 0.55-T Low-Field Scanner

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Biomedical Engineering
• Medical Physics

Background:

• Conventional 2D breath-hold myocardial mapping is slow and offers limited heart coverage.
• Existing methods require contrast agents for comprehensive tissue characterization.
• There is a need for faster, free-breathing techniques with whole-heart coverage.

Purpose of the Study:

• To develop and evaluate a novel free-breathing 3D joint T1/T1ρ mapping sequence with Dixon encoding.
• To enable simultaneous, contrast-agent-free myocardial tissue characterization and whole-heart visualization.
• To achieve isotropic spatial resolution in a single scan on a clinical 0.55-T MR scanner.

Main Methods:

• A novel free-breathing 3D sequence with interleaved volumes for T1 and T1ρ encoding.
• Two-echo Dixon readout and 2D image navigators for 100% respiratory scan efficiency.
• Nonrigid respiratory motion-corrected iterative SENSE reconstruction with patch-based denoising.

Main Results:

• The proposed 3D sequence achieved good correlation with 2D spin-echo reference measurements in phantoms.
• In healthy subjects, T1 and T1ρ values were measured as 743±19 ms and 46.9±2.7 ms, respectively.
• Promising results were observed when compared to 2D late-gadolinium enhancement imaging in a patient.

Conclusions:

• The developed sequence enables simultaneous 3D whole-heart joint T1/T1ρ mapping and water-fat imaging in approximately 11 minutes.
• The technique demonstrates good agreement with conventional methods in phantoms and healthy subjects.
• This approach offers a promising, contrast-agent-free method for comprehensive myocardial tissue characterization.