Usefulness of ultrasonic strain measurement-based mechanical properties imaging technique - toward realization of combined short time diagnosis/treatment

For various soft tissues (e.g., liver, breast, etc.), we are developing the ultrasonic strain measurement-based mechanical properties (shear modulus, visco-shear modulus, etc.) reconstruction/imaging technique. To clarify the limitation of our quantitative reconstruction/imaging technique as a diagnostic tool for differentiating malignancies, together with improving the spatial resolution and the dynamic range we are collecting the clinical reconstruction image data. Furthermore, we are applying our technique as a monitoring technique for the effectiveness of chemotherapy (e.g., anticancer drug, ethanol, etc.), cryotherapy and thermal therapy (e.g., micro, and rf electromagnetic wave, HIFU, LASER, etc.). As soft tissues are deformed in 3-D space due to externally situated quasi-static and/or low frequency mechanical sources, multidimensional signal processing improves strain measurement accuracy, and consequently modulus reconstruction accuracy. We have verified these through simulations and phantom/animal in vitro experiments. Briefly, here we discuss the limitations of low dimensional signal processing. Moreover, both on differential diagnosis for these human in vivo malignancies and monitoring for the therapies, we exhibit the superiority of our quasi-real time imaging (using conventional US equipment) to conventional B-mode imaging. Our technique is available as a clinical visualization technique both for diagnosis and treatment, and monitored mechanical properties data can also be effectively utilized as the measure for controlling the therapies, i.e., the exposure energy, the foci, the exposure interval, etc. In the near future, suitable combination of various simple and low-invasive therapies with our imaging open up a new clinical style allowing diagnosis and the subsequently immediate treatment. This must substantially reduce the total medical expenses.