Free-breathing 3D cardiac extracellular volume (ECV) mapping using a linear tangent space alignment (LTSA) model.

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Quantitative MRI Techniques

Background:

• Accurate extracellular volume (ECV) mapping is crucial for assessing myocardial tissue characteristics.
• Existing ECV mapping methods often require breath-holding, limiting whole-heart coverage and patient comfort.

Purpose of the Study:

• To develop and validate a novel free-breathing, 3D cardiac ECV mapping method at 3 Tesla.
• To enable comprehensive, whole-heart ECV assessment without breath-holding constraints.

Main Methods:

• A free-breathing, 3D electrocardiogram-gated inversion recovery sequence with spoiled gradient echo readout was employed for T1 mapping.
• High-frame-rate dynamic images were reconstructed using a linear tangent space alignment model from sparsely sampled (k,t)-space data.
• Joint T1 and transmit B1 estimation, along with a time-varying T1 model, were utilized for accurate pre- and post-contrast T1 mapping.

Main Results:

• The developed method successfully generated 3D ECV maps of the whole heart at 3 Tesla in healthy volunteers.
• Achieved a spatial resolution of 1.9 × 1.9 × 4.5 mm³ with a total scan time of approximately 10-11 minutes.
• Qualitative and quantitative comparisons showed good agreement between the proposed 3D ECV maps and the conventional 2D MOLLI method.

Conclusions:

• The novel free-breathing 3D cardiac ECV mapping method is feasible and effective for whole-heart assessment at 3 Tesla.
• This technique offers a practical imaging time and provides ECV values comparable to established methods.
• The method holds promise for improved non-breath-holding cardiovascular magnetic resonance imaging.