Technical note: Accelerated nonrigid motion-compensated isotropic 3D coronary MR angiography.

Area of Science:

• Cardiovascular Imaging
• Magnetic Resonance Imaging
• Medical Technology

Background:

• Coronary magnetic resonance angiography (CMRA) is crucial for non-invasive assessment of coronary artery disease.
• Traditional CMRA techniques often require long scan times and are susceptible to motion artifacts, limiting their clinical utility.
• Accelerated imaging techniques are needed to improve efficiency and patient comfort in 3D whole-heart CMRA.

Purpose of the Study:

• To develop and evaluate an accelerated, nonrigid motion-compensated 3D whole-heart CMRA technique using Cartesian acquisition.
• To achieve efficient and isotropic image acquisition for improved visualization of coronary arteries.
• To reduce scan times significantly while maintaining diagnostic image quality.

Main Methods:

• Implemented a highly efficient 3D CMRA by combining compressed sensing (CS) reconstruction with a nonrigid motion compensation framework.
• Utilized a variable-density Cartesian acquisition (VD-CAPR) with undersampling for faster data acquisition.
• Employed a two-step motion correction: beat-to-beat 2D translational correction and bin-to-bin 3D nonrigid correction using CS-reconstructed images.

Main Results:

• Achieved isotropic 1.2-mm 3D whole-heart CMRA in approximately 5 minutes, representing an ~8x acceleration.
• Acquired images comparable in quality (vessel sharpness and length) to a conventional twofold accelerated navigator-gated acquisition.
• Demonstrated significantly faster scan times (up to four times) compared to the reference method without compromising diagnostic quality.

Conclusions:

• Demonstrated the feasibility of a highly efficient, motion-compensated reconstruction framework for accelerated 3D CMRA in healthy subjects.
• The proposed technique offers a promising approach for rapid, high-quality coronary artery imaging.
• Further research is warranted to evaluate the clinical impact and diagnostic performance of this accelerated CMRA method.