Trajectory correction based on the gradient impulse response function improves high-resolution UTE imaging of the...

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering

Background:

• Ultra-fast imaging (UTE) sequences are susceptible to gradient field imperfections like eddy currents and system delays.
• Accurate gradient waveform information is crucial for high-resolution UTE musculoskeletal imaging.

Purpose of the Study:

• To utilize gradient impulse response function (GIRF) measurement for estimating actual readout gradient waveforms.
• To demonstrate the significance of precise gradient waveform knowledge in high-resolution UTE musculoskeletal imaging.

Main Methods:

• Gradient impulse response function (GIRF) was measured using a 3 Tesla scanner's standard hardware.
• 3D radial UTE data were acquired and reconstructed twice: once with GIRF-corrected waveforms and once with nominal-corrected waveforms.
• Experiments included phantom scans, in vivo knee imaging, and in vivo spine fracture imaging.

Main Results:

• Nominal-corrected waveforms resulted in image blurring and edge artifacts.
• GIRF-corrected waveforms significantly reduced blurring and artifacts in phantom and knee UTE scans.
• GIRF-based correction preserved thin bone structures in lumbar spine UTE images, which disappeared with nominal correction.

Conclusions:

• A GIRF-based trajectory correction method, using standard scanner hardware, enhances the quality of high-resolution UTE musculoskeletal imaging.
• Precise gradient waveform estimation is vital for artifact reduction and detail preservation in UTE MRI.