3-D Handheld Harmonic Motion Imaging System for Breast Tumor Assessment: A Clinical Feasibility Study

Area of Science:

• Medical Imaging
• Ultrasound Elastography
• Biomedical Engineering

Background:

• Harmonic Motion Imaging (HMI) is a displacement-based ultrasound elastography technique.
• Single Transducer HMI (ST-HMI) improved excitation and tracking but was limited to 2D imaging.
• There was a need for a 3D HMI system for comprehensive tumor assessment.

Purpose of the Study:

• To develop and validate a 3D Harmonic Motion Imaging (3D-HMI) system using a handheld device.
• To assess the feasibility, accuracy, and efficiency of 3D-HMI for volumetric stiffness mapping.
• To evaluate the potential of 3D-HMI in characterizing breast tumors.

Main Methods:

• Utilized a row-column array (RCA) for harmonic radiation force generation (200/400 Hz).
• Employed interleaved excitation and receive sequences for displacement estimation.
• Validated the system using phantoms with varying stiffness inclusions and in human breast tumor samples.

Main Results:

• The 3D-HMI system accurately detected all inclusions (2.2-13.2 mm) in phantoms, including the smallest at 2 mm.
• Estimated normalized displacement was inversely proportional to the stiffness ratio of inclusions to background.
• Successfully reconstructed 3D HMI displacement maps of human breast tumors, including fibroadenoma and invasive ductal carcinoma.

Conclusions:

• 3D-HMI is a feasible, accurate, and time-efficient method for volumetric relative stiffness mapping.
• The handheld 3D-HMI system enhances the clinical potential for assessing entire tumor volumes.
• This technique offers a valuable tool for characterizing mechanical properties in a manner similar to conventional breast sonography.