HIGH FREQUENCY SONOGRAPHY FOR CHARACTERIZING INDIVIDUAL TISSUE IN PULLEY SYSTEM

Tai-Hua Yang, Yi-Hsun Lin, Wei-Jr Lin, Li-Chieh Kuo, I-Ming Jou, Shyh-Hau Wang, Fong-Chin Su Institute of Biomedical Engineering, Department of Computer Science & Information Engineering & Institute of Medical Informatics Department of Occupational Therapy, Department of Orthopedics, Medical Device Innovation Center, National Cheng Kung University, Taiwan, R.O.C. Department of Orthopedics, China Medical University Hospital, Taiwan, R.O.C. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic Rochester, Rochester, Minnesota Email address: fcsu@mail.ncku.edu.tw INTRODUCION Trigger finger is one of the most common complaints in a hand surgeon’s clinics. It was characterized by loss of normal gliding between tendon and pulley even with popping sensation or painful locking [1]. Sonography has been widely used to evaluate and diagnose the trigger finger for years by measuring the thickness and echogenicity of the A1 pulley, tendon thickness, fluid collection and other related parameters [2,3,4]. It also was used to assist release of A1 pulley [5]. For an average thickness of normal pulley around 0.5 mm, the resolution of clinical ultrasound scanners (frequency: 12 ~ 17 MHz) is inadequate to sensitively differentiate the complexity of tissues in the pulley system. Recently, ultrasounds with frequencies higher than 20 MHz have been used to measure the skin, the eye, and vasculature...etc. It can provide more detailed information and make imaging of soft tissues readily, so ultrasound signals can be utilized to further characterize properties of soft tissues quantitatively [6]. It is crucial to verify the quantitative acoustic properties of normal pulley system prior to they are further applied to clinical diagnosis. In this study, we used 31 MHz high-frequency ultrasound images incorporated with ultrasonic parameters to characterize the A1 pulley and adjacent soft tissues.