Development Of A High Frequency Acoustic Radiation Force Impulse Imaging System For Detecting The Elastic Properties Of Cornea Tissue

• Main Authors: Shih, Cho-Chiang, 史卓強
• Other Authors: Huang, Chih-Chung
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/29589295271556093897

碩士 === 輔仁大學 === 電機工程學系 === 100 === Recently, the myopia populations has grown up. The patients suffering from cornea lesions, caused by wearing the contact lenses for longtime and undergoing the laser eye surgery, have also show their crucial. The purpose of this study is to develop the high resolution of high frequency acoustic radiation force impulse imaging system to detect the elastic properties of cornea. A high frequency dual confocal ultrasound transducer was used in these experiments. The central frequency of the outer element is 10 MHz, which is used to induce the localized displacement of tissue. The central frequency of the inner element is 50 MHz, which is used to detect the localized displacement of tissue. In order to scan the tissue with different depths, the dual confocal ultrasound transducer was attached on the 3-axis motor system. The ultrasonic scatter signals fetched from the tissue were analyzed to get the distribution of displacements under different locations and different depths by cross-correlation. High frequency radiation force image can be constructed by combining these distributions of displacements. System verifications were performed on three kinds of tissue mimicking gelatin-based phantoms. The results indicate that the system can be used to distinguish the different elastic regions with minimum value of 0.4 mm. In the in vitro porcine cornea experiments, the system was utilized to detect the elastic properties for both healthy and localized sclerosing cornea. The results demonstrated that the inhomogeneous elastic distribution in the cornea tissue can be unidentified by analyzing the tissue displacement which is generated by the acoustic radiation force. Finally, the high resolution of high frequency acoustic radiation force impulse image can be constructed to provide enough elastic properties information of cornea.