Exploration of highly accelerated magnetic resonance elastography using high-density array coils.

Area of Science:

• Biophysics
• Medical Imaging
• Materials Science

Background:

• Magnetic Resonance Elastography (MRE) measures tissue mechanics using shear waves and MRI.
• High-density array coils accelerate MRE acquisition, enabling high-resolution imaging with reduced scan times using single echo acquisition (SEA).

Purpose of the Study:

• To evaluate the efficacy of high-density array coils for accelerated, high-resolution MRE.
• To investigate MRE's capability in assessing mechanical property variations with temperature.

Main Methods:

• Utilized 64-channel uniplanar and 32x32 channel biplanar receive arrays for MRE wave image acquisition.
• Employed single echo acquisition (SEA) and multiple echoes for accelerated imaging, with motion-sensitizing gradients to encode displacements.
• Investigated temperature-dependent stiffness changes and used a custom gradient coil for phase compensation.

Main Results:

• Demonstrated SEA MRE imaging of shear wave propagation in agar samples with varying stiffness.
• Acquired high-resolution MRE datasets (156 µm × 125 µm × 1,000 µm) in as few as 64 echoes, achieving high acceleration factors.
• Observed changes in mechanical wavelength corresponding to temperature-induced agar property variations.

Conclusions:

• High-density arrays facilitate MRE acquisition of single frames per echo, beneficial for non-repeatable or destructive testing.
• Highly accelerated, high-resolution MRE is achievable with large coil arrays, offering improved resolution at moderate acceleration rates.