Free-Running Three-Dimensional Cardiac Extracellular Volume Mapping in a Single Scan With Mid-Scan Contrast Injection

Area of Science:

• Cardiovascular imaging
• Magnetic Resonance Imaging (MRI)
• Medical diagnostics

Background:

• Accurate extracellular volume (ECV) mapping is crucial for diagnosing and monitoring various cardiac conditions.
• Traditional ECV mapping methods often require multiple scans or breath-holds, limiting their clinical applicability.
• Developing a single-scan, free-running 3D ECV mapping technique can significantly improve patient comfort and workflow efficiency.

Purpose of the Study:

• To develop and validate a novel free-running, three-dimensional (3D) cardiac magnetic resonance imaging (MR) method for extracellular volume (ECV) mapping.
• To achieve ECV mapping within a single, continuous scan with contrast agent administration partway through the acquisition.
• To enable comprehensive 3D cardiac assessment in a single imaging session.

Main Methods:

• Utilized a single, free-running 3D cardiac MR scan with an inversion recovery (IR) sequence and spoiled gradient-echo readout.
• Administered contrast agent mid-scan and reconstructed dynamic images using a linear tangent space alignment (LTSA) model.
• Estimated pre- and post-contrast T1* values, synthesized cardiac cine images, and calculated 3D ECV maps using measured hematocrit levels.

Main Results:

• Demonstrated feasibility in three healthy subjects using a 3T MR scanner.
• ECV maps showed good agreement with the established MOLLI method, with average myocardial ECV of 29.82% ± 2.45%.
• Synthesized cine images accurately captured cardiac motion, yielding an ejection fraction of 63.3% ± 8%, consistent with literature values.

Conclusions:

• A novel approach for 3D cardiac ECV mapping in a single, free-running scan has been successfully developed.
• The method integrates contrast injection mid-scan, allowing for efficient and comprehensive cardiac assessment.
• This technique offers a promising advancement for clinical cardiovascular imaging and research.