Retrospective respiratory motion correction for navigated cine velocity mapping

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Biomedical Engineering

Background:

• High-resolution cardiac imaging often requires long scan times, precluding breath-hold acquisition.
• Existing free-breathing techniques like navigator gating reduce respiratory motion artifacts but leave residual blurring, especially late in the cardiac cycle.
• This blurring impairs accurate blood flow quantification, particularly in high-flow diastolic phases.

Purpose of the Study:

• To extend navigator gating and slice tracking by using navigator data for in-slice motion correction throughout the cardiac cycle.
• To improve image quality and enable accurate free-breathing coronary flow quantification.

Main Methods:

• A 2D cine phase contrast sequence with navigator gating and slice position correction was employed.
• Navigator data were recorded with k-space data for postprocessing.
• In-plane respiratory motion components were estimated and corrected using the Fourier shift theorem.

Main Results:

• Phantom experiments validated the correction algorithm across different slice angulations.
• In vivo, the method significantly improved vessel sharpness by 16+/-11% in healthy volunteers.
• Retrospective correction led to a 16+/-13% increase in volume flow rates, demonstrating improved quantification.

Conclusions:

• Retrospective respiratory motion correction for navigated 2D cine velocity mapping effectively addresses in-plane motion.
• This technique enhances image quality, particularly for cardiac phases late in the cycle.
• The method shows significant promise for free-breathing coronary flow quantification.