Stenosis detection in fallopian tubal model using ultrasonic measurement

摘要

Recently, infertility has been considered to be an urgent problem. One of the causes of female infertility is tubal infertility. As an examination for tubal infertility, hysterosalpingography is often used. It requires a contrast medium injected from the ostium uteri, and infertility doctors observe whether the medium smoothly flows by radiating X-rays. In other words, it is a non-invasive examination that imposes pain and/or bleeding on subjects. A method of detecting whether there is stenosis in models of fallopian tubes with no medium injection is presented, assuming that silicone tubes are phantoms of fallopian tubes. A lump of the polyester threads is considered to be a stenosis, and inserted in each tube. The method processes the portion of the reflected wave observed by the ultrasonic device. The portion corresponds to the inside of the tube. It is divided into several short-time intervals each of which the length is equal. The method obtains the maximum amplitude value and the minimum amplitude value in each interval. It next generates the frequency distribution associated with the difference between the maximum amplitude value and the minimum amplitude value in each interval. In the distribution, the axis of ordinate and that of abscissa are for the number of differences and for the regularly divided amplitude, respectively. The method employs a ten-dimensional vector with the numbers of differences as element values to specify the portion to be processed, and distinguishes potions with lumps from those without lumps using support vector machines. Experimental results reveal that the method achieves high accuracy in detecting stenosises. This work was supported in part by Terumo Foundation for Life Sciences and Arts.