Ultrasound elastography: Development of novel technologies and standardization

Ultrasound elastography has been developed as a modality that provides novel diagnostic information on tissue stiffness and replaces conventional palpation used for breast examination. Although various techniques for ultrasound elastography have been proposed in the 1990s, it was difficult to develop a practical system for clinical use. The combined autocorrelation method of producing elasticity images with high-speed processing and accuracy was developed by our group. It achieves a wide dynamic range for strain estimation. In 2003, we developed the world's first commercialized equipment for elastography for clinical use. It was revealed that even nonexperts could achieve precise diagnosis of breast cancer on the basis of ultrasound elastography results as well as experts since the criterion on tissue elasticity is much simpler than conventional B-mode images. Nowadays, there are different types of equipment for elastograpy, then features and equipment of each method, i.e., their merits and limitations, must be clarified for their appropriate use. Recently, to help users of ultrasound elastography, academic societies of medical ultrasound, such as WFUMB, EFSUMB, and JSUM, have started to prepare guidelines on such methods. In this review, I outline the development of ultrasound elastography and the recent steps toward its standardization.