Feasibility of In-vivo Determination of Absolute Elastic Tissue

University Of Wisconsin-Madison, Madison WI

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Abstract

[unreadable] DESCRIPTION (provided by applicant): The proposed research will investigate the feasibility of integrating a force sensor into a two-dimensional (2D) ultrasound transducer array for measuring the contact force during ultrasound elasticity imaging procedures. The contact force information will provide an absolute measure of the time at which contact is made with the skin surface and the total force applied at any point during scanning. That information will be used to calibrate (relative) mechanical strain images for comparing strain image contrast changes with increasing deformation and can be used for absolute elastic modulus reconstruction. Preliminary data demonstrate the potential gain from such a device. First, significant improvement in strain image quality is available when 3D tracking, enabled by a 2D array, is employed. Second, the elastic nonlinearity of various tissue types appears to be unique, and of potential significance, but a quantitative measure of the contact force is needed for an unbiased comparison of data. Third, recent results suggest it is possible to image the elastic nonlinearity parameter of breast tissues, and in vitro measurements of breast tissue samples found that ductal carcinoma in situ (DCIS) has the highest elastic nonlinearity. So, it might be possible to directly image the 3D distribution of DCIS in the breast. This could have a profound impact on breast cancer screening, early detection and treatment prognosis. The study involves a limited Phase I clinical trial to test performance of the combined imaging/force sensor device in a clinical environment. The subject pool for testing this technology will focus on patients with the highest probability of malignancy (i.e., BIRADS 4b or 4c) who are scheduled for ultrasound-guided biopsy. Feasibility of the device will be demonstrated if 2-D B-mode images are suitable for guiding clinical breast elastography, if the volume data acquisition rate is sufficiently fast to allow freehand elasticity imaging, if reliable, stable, force sensor measurements are obtained, and if the force sensor is robust, sensitive and has sufficient dynamic range to determine the initial contact with the skin surface and the total contact force during clinical breast imaging. If feasibility is demonstrated, future funding will be requested to optimize the combined transducer for a more comprehensive clinical trial of nonlinear breast elasticity imaging potentially targeting DCIS detection. PUBLIC HEALTH RELEVANCE: This is a proposal to study the feasibility of creating a two-dimensional ultrasound array transducer that has an integrated force sensor for detecting the contact force during elasticity imaging experiments. This transducer will enable clinically estimating the nonlinear mechanical properties of soft tissues and might eventually enable directly imaging ductal carcinoma in situ and thereby improve early detection of breast cancer. [unreadable] [unreadable] [unreadable]