Single breath-hold 3D cardiac T₁ mapping using through-time spiral GRAPPA

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Physics
• Biomedical Engineering

Background:

• Cardiac T1 relaxation time quantification is crucial for diagnosing heart diseases.
• Current 2D T1 mapping techniques are limited by motion artifacts, restricting whole-heart evaluation.
• A need exists for faster, motion-robust methods for clinical T1 assessment.

Purpose of the Study:

• To develop and validate an electrocardiogram (ECG)-triggered, three-dimensional (3D) Look-Locker method for rapid cardiac T1 measurement.
• To assess the accuracy and feasibility of the proposed technique in phantoms and healthy subjects.
• To enable comprehensive cardiac T1 mapping within a single breath-hold period.

Main Methods:

• Developed an ECG-triggered 3D Look-Locker sequence using spoiled gradient-echo with a stack-of-spirals trajectory.
• Employed through-time non-Cartesian generalized autocalibrating partially parallel acquisition (GRAPPA) for accelerated data acquisition.
• Investigated magnetic resonance parameter effects via Bloch equation simulations and validated accuracy in phantoms and healthy volunteers.

Main Results:

• Simulations and phantom studies showed close agreement with reference methods across various T1 values.
• In vivo studies achieved rapid 3D cardiac T1 mapping (2x2x8 mm3 resolution) in ~12 seconds.
• Mean T1 values in healthy volunteers at 3T were: myocardium 1311±66 ms, blood 1890±159 ms.

Conclusions:

• A novel 3D T1 mapping technique utilizing non-Cartesian parallel imaging was successfully developed.
• The technique provides fast and accurate T1 quantification of cardiac tissues.
• This method facilitates comprehensive cardiac assessment in a single short breath-hold, improving clinical applicability.