High-frequency mode conversion technique for stiff lesion detection with magnetic resonance elastography (MRE)

Area of Science:

• Biomedical Imaging
• Medical Physics
• Diagnostic Techniques

Background:

• Magnetic resonance elastography (MRE) relies on shear wave propagation, which attenuates rapidly in soft tissues.
• Distinguishing stiff lesions from surrounding soft tissue remains a challenge in conventional MRE.

Purpose of the Study:

• To introduce a novel MRE technique for qualitative detection of stiff lesions using mode conversion of longitudinal waves.
• To evaluate the feasibility and accuracy of this new technique in phantoms, ex vivo, and in vivo.

Main Methods:

• Introducing high-frequency, minimally-attenuating longitudinal waves into tissue.
• Utilizing mode conversion at tissue interfaces to generate detectable shear waves in stiff regions.
• Comparing results with conventional MRE for accuracy in stiffness measurements.

Main Results:

• The technique successfully depicted stiff regions mimicking tumors in tissue phantoms and ex vivo breast tissue.
• In vivo imaging clearly distinguished liver metastases in a patient.
• Preliminary data suggest improved accuracy in quantitative stiffness measurements compared to conventional MRE due to shorter shear wavelengths.

Conclusions:

• This novel MRE technique effectively detects stiff lesions by leveraging longitudinal wave mode conversion.
• It shows promise for localizing suspicious neoplasms and may complement existing sensitive characterization methods.