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Cardiac Magnetic Resonance Imaging at 7 Tesla
Published on: January 6, 2019
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Three-dimensional sector-wise golden angle-improved k-space uniformity after electrocardiogram binning
Alexander Fyrdahl1, Amanda Ullvin1, Joao G Ramos1
1Department of Clinical Physiology, Karolinska University Hospital, and Karolinska Institutet, Stockholm, Sweden.
Magnetic Resonance in Medicine
|May 15, 2023
Summary
A new 3D sector-wise golden-angle (3D-SWIG) method improves k-space uniformity in cardiovascular MRI. This technique enables fast, free-breathing cardiac imaging with reproducible results.
Area of Science:
- Medical Imaging
- Cardiovascular Magnetic Resonance (CMR) Imaging
- Image Reconstruction
Background:
- Cardiovascular MR (CMR) cine imaging requires efficient k-space sampling for accurate functional assessment.
- Existing 3D radial trajectories can suffer from non-uniform k-space coverage after physiological binning, limiting acquisition speed.
- Electrocardiogram (ECG) gating is crucial for synchronizing CMR data acquisition with cardiac motion.
Purpose of the Study:
- To develop and evaluate a novel 3D sector-wise golden-angle (3D-SWIG) profile ordering scheme for cardiovascular MR cine imaging.
- To assess the ability of 3D-SWIG to maintain high k-space uniformity after electrocardiogram (ECG) binning.
- To enable faster, free-breathing CMR acquisitions with improved data quality.
Main Methods:
- A 3D-SWIG radial trajectory was implemented on a 1.5T CMR scanner using a balanced SSFP sequence.
- k-space was divided into wedges, with each wedge acquired per heartbeat, optimizing coverage after ECG binning.
- Numerical simulations compared 3D-SWIG against double golden angle and spiral phyllotaxis trajectories; in vivo studies involved 17 patients comparing free-breathing 3D-SWIG with breath-held 2D Cartesian cine.
Main Results:
- Numerical simulations demonstrated superior k-space sampling uniformity and smaller readout steps for 3D-SWIG compared to other methods.
- In vivo studies showed highly reproducible left ventricular ejection fraction measurements from 48-heartbeat free-breathing 3D-SWIG acquisitions.
- 3D-SWIG results closely agreed with conventional breath-held 2D Cartesian cine (mean difference -3.1 ± 3.5% points).
Conclusions:
- The 3D-SWIG acquisition scheme provides a straightforward method for achieving enhanced k-space uniformity post-ECG binning.
- This technique facilitates whole-heart cine imaging during free breathing with acquisition times under one minute.
- 3D-SWIG shows significant potential for improving the efficiency and feasibility of cardiovascular MR cine imaging.
