Extended MRI-based PET motion correction for cardiac PET/MRI.

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Cardiovascular Imaging

Background:

• Hybrid PET/MRI offers advanced diagnostic capabilities but is challenged by respiratory motion artifacts.
• Current motion correction methods for hybrid PET/MRI often only correct PET data acquired during specific MRI sequences.
• A comprehensive MRI-based respiratory motion correction for the entire PET acquisition is needed to improve image quality.

Purpose of the Study:

• To introduce and evaluate an MRI-based respiratory motion correction method for complete PET data in hybrid PET/MRI.
• To assess the impact of this novel correction method on image quality metrics in cardiac PET scans.
• To compare the proposed method against existing non-motion-corrected approaches.

Main Methods:

• The study included 27 patients undergoing cardiac 18F-FDG or 18F-FCH PET/MRI.
• A 2D image navigator (iNAV) and respiratory belt recorded motion throughout the PET/MRI examination.
• PET data was binned, reconstructed using iNAV-based motion fields, and compared between motion-corrected (MC) and non-motion-corrected (NMC) datasets, with and without cardiac gating.

Main Results:

• Motion-corrected (MC) datasets showed significantly higher SUVmax and TBRmax values compared to non-motion-corrected (NMC) datasets (p < 0.01).
• MC and gated (MC_G) reconstructions also demonstrated higher values than NMC and gated (NMC_G) reconstructions, though TBRmax difference was not significant (p=0.16).
• Respiratory motion correction did not alter the signal-to-noise ratio of the images.

Conclusions:

• The proposed MRI-based respiratory motion correction method effectively enhances cardiovascular PET image quality in hybrid PET/MRI.
• The technique leads to significant improvements in SUVmax and TBRmax, crucial for accurate diagnosis.
• This method maintains image signal-to-noise ratio, ensuring diagnostic reliability.