Magnetic resonance elastography in the liver at 3 Tesla using a second harmonic approach

Area of Science:

• Medical Imaging
• Biophysics
• Radiology

Background:

• Magnetic Resonance Elastography (MRE) shows promise for diagnosing liver conditions.
• Current 1.5T MRE methods have limitations including long scan times and lower signal-to-noise ratios.
• Higher field strengths like 3.0T offer potential for MRE improvements.

Purpose of the Study:

• To develop and evaluate a modified MRE sequence for liver imaging at 3.0T.
• To address the limitations of 1.5T MRE, specifically scan time and signal-to-noise.
• To compare 3.0T MRE results with established 1.5T MRE findings.

Main Methods:

• A novel MRE sequence was implemented for 3.0T MRI, utilizing a second harmonic approach with a short TE.
• Techniques included stronger motion encoding gradients, shorter RF pulses, and an echo-planar imaging (EPI) readout.
• Higher density sampling of the phase waveform was employed for calculating shear stiffness and viscosity.

Main Results:

• The 3.0T MRE sequence significantly reduced scan time by approximately 50% compared to 1.5T.
• The modified sequence maintained image quality and avoided phase image artifacts.
• Localized and global liver stiffness and viscosity measurements at 3.0T correlated well with previous 1.5T results.

Conclusions:

• The developed 3.0T MRE sequence is effective for liver imaging, offering reduced scan times and comparable diagnostic accuracy to 1.5T.
• This advancement holds potential for more efficient and robust liver stiffness assessment.
• No significant differences were observed between localized and global MRE measurements in healthy subjects.