3D MR elastography at 0.55 T: Concomitant field effects and feasibility

Area of Science:

• Medical Imaging
• Biophysics
• Biomedical Engineering

Background:

• Magnetic Resonance Elastography (MRE) assesses tissue stiffness.
• Lower magnetic field strengths (0.55 T) offer potential advantages in cost and accessibility.
• Assessing hepatic (liver) biomechanical properties is crucial for diagnosing liver diseases.

Purpose of the Study:

• To evaluate the feasibility of 3D MRE at 0.55 T for liver imaging in healthy volunteers.
• To investigate the impact of concomitant magnetic fields on MRE at 0.55 T.
• To compare MRE-derived biomechanical parameters at 0.55 T with those obtained at 3 T.

Main Methods:

• Numerical simulations and phantom experiments were used to assess concomitant field effects.
• A Hadamard-encoded 3D MRE sequence was applied at 0.55 T in five healthy volunteers.
• A reference 3D MRE scan at 3 T was performed for comparison, analyzing shear modulus, wave speed, and loss modulus.

Main Results:

• Concomitant field effects were found to be negligible at 0.55 T.
• Biomechanical parameters (|G*|, Cs, G″) at 0.55 T showed good agreement with 3 T measurements.
• A 2.1-fold decrease in apparent signal-to-noise ratio (SNR) was observed at 0.55 T compared to 3 T.

Conclusions:

• Hepatic 3D MRE is feasible and demonstrates promising results at 0.55 T.
• Lower-field MRE can provide reliable biomechanical parameter estimations.
• Further research can explore the clinical utility of 0.55 T MRE for liver disease assessment.