Phase and amplitude correction for multi-echo water-fat separation with bipolar acquisitions

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Biomedical Engineering

Background:

• Bipolar MRI acquisitions efficiently collect multi-point water-fat data.
• System nonidealities like eddy currents cause phase and amplitude errors, hindering accurate water-fat separation.

Purpose of the Study:

• To develop and validate a method for correcting 2D phase and amplitude errors in bipolar water-fat separation.
• To improve the uniformity and accuracy of water-fat separation in MRI.

Main Methods:

• A novel method utilizing low-resolution reference data with reversed gradient polarities was developed.
• Two-dimensional phase errors are estimated and corrected using pairs of oppositely polarized low-resolution data.
• Corrected data are combined for robust water-fat separation.

Main Results:

• The proposed method effectively removes high-order phase and amplitude errors.
• Successful validation was demonstrated in both phantom and in vivo experiments.
• The method showed efficacy even with obliquely oriented scans.

Conclusions:

• The developed method enables uniform water-fat separation for bipolar multi-echo acquisitions.
• Accurate correction of high-order phase errors is crucial for reliable water-fat separation in advanced MRI techniques.