Cartesian dictionary-based native T₁ and T₂ mapping of the myocardium

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Quantitative Myocardial Imaging
• Biomedical Engineering

Background:

• Accurate native myocardial T1 and T2 mapping is crucial for diagnosing cardiovascular diseases.
• Existing mapping techniques can be limited by acquisition speed and accuracy.

Purpose of the Study:

• To implement and evaluate a novel dictionary-based technique, Multimapping, for simultaneous native myocardial T1 and T2 mapping.
• To assess the feasibility of using a conventional Cartesian sampling strategy.

Main Methods:

• Multimapping employs single-shot Cartesian acquisitions over 10 cardiac cycles with specific inversion and T2 preparation pulses.
• The technique involves matching acquired k-space center data to a dictionary of T1 and T2 values.
• Phantom and in vivo experiments were conducted on 16 healthy subjects and 3 patients with cardiovascular disease.

Main Results:

• Phantom studies demonstrated good agreement with reference T1 and T2 values, with no heart-rate dependency.
• In vivo, Multimapping yielded significantly different T1 values compared to a reference method (1114 ± 14 ms vs. 991 ± 26 ms).
• Multimapping showed significantly lower T2 values and spatial variability (47.1 ± 1.3 ms, 5.8 ± 1.0 ms) compared to the reference (54.7 ± 2.2 ms, 8.4 ± 2.0 ms).

Conclusions:

• Multimapping successfully enables simultaneous native myocardial T1 and T2 mapping using a standard Cartesian trajectory.
• The technique demonstrates promising in vivo image quality and accurate parameter quantification.
• This method offers a potential advancement for quantitative cardiovascular MRI.