Repeatability of Linear and Nonlinear Elastic Modulus Maps From Repeat Scans in the Breast

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Soft Tissue Mechanics

Background:

• Compression elastography enables in vivo measurement of large soft tissue deformations.
• Nonlinear elastic modulus maps (NEMs) are being evaluated for breast cancer assessment.
• Assessing the repeatability of NEMs is essential for clinical validation.

Purpose of the Study:

• To evaluate the repeatability of linear and nonlinear elastic modulus maps derived from repeat compression elastography measurements.
• To assess the consistency of NEMs in soft tissues under controlled loading conditions.

Main Methods:

• In vivo data acquired using a custom uniaxial compression device with force feedback.
• Plane-wave imaging at 200 Hz frame-rate with an 8N ramp-and-hold compressive force.
• 2D block-matching and cross-correlation for sub-sample displacement tracking.
• Iterative optimization to estimate elasticity parameters using a modified Veronda-Westmann model.

Main Results:

• Repeat scans demonstrated consistency in reconstructed linear and nonlinear elastic modulus maps.
• High strain levels are necessary for reliable recovery of nonlinearity parameters.
• B-mode images, strain images, and modulus maps were compared between repeat measurements.

Conclusions:

• Reconstructed modulus maps are consistent when imaging the same tissue region with sufficient strain.
• Compression elastography shows promise for repeatable, quantitative assessment of soft tissue elasticity in vivo.
• These findings support the clinical utility of NEMs in breast cancer evaluation.