Cardiac real-time MRI using a pre-emphasized spiral acquisition based on the gradient system transfer function.

Area of Science:

• Cardiovascular Imaging
• Magnetic Resonance Imaging
• Medical Physics

Background:

• Segmented Cartesian acquisition is the current standard for cardiac functional MRI but requires breath-holds and is lengthy.
• Existing methods pose challenges for patients with arrhythmias or breathing difficulties.
• There is a need for faster, more accessible cardiac MRI techniques.

Purpose of the Study:

• To develop and evaluate a real-time cardiac MRI technique using undersampled spiral trajectories with gradient pre-emphasis.
• To overcome limitations of breath-hold Cartesian acquisition for cardiac functional MRI.
• To enable faster and more patient-friendly cardiac MRI examinations.

Main Methods:

• Implemented automatic gradient waveform pre-emphasis to correct gradient inaccuracies.
• Utilized compressed sensing-accelerated, spoiled gradient-echo sequence with spiral k-space trajectories.
• Tested in phantom studies and real-time cardiac MRI of healthy subjects and heart failure patients.

Main Results:

• Pre-emphasis effectively reduced artifacts from k-space misregistrations.
• Achieved real-time dynamic cardiac imaging (<50 ms temporal resolution) with high spatial resolution (1.34 × 1.34 mm²).
• Total scan time for whole-heart coverage was under 50 seconds, with comparable results to the reference method.

Conclusions:

• The proposed technique allows high-resolution, real-time cardiac MRI without breath-holds or ECG gating.
• Significantly reduces the total duration of a functional cardiac MRI exam to under one minute.
• Offers a more accessible and efficient alternative for cardiac functional MRI.