Quantitative Evaluation of Female Pelvic Floor Muscle Biomechanics Using Ultrasound Elastography

Abstract

Female pelvic floor dysfunction is a common disease which has become one of the five common chronic diseases threatening women's health. As the supporting structures, pelvic floor muscle is critical to support the pelvic organs, maintain continence, and prevent prolapse. The quantitative evaluation of pelvic floor muscle biomechanics is of great value for the diagnosis and treatment of female pelvic floor dysfunction. Our study aims to propose a noninvasive, quantitative, and objective method for motion analysis of the pelvic floor muscles. Ultrasound data, force data during continuous contractive activities from 37 subjects are synchronously collected using an ultrasound scanner and a self-designed intravaginal pressure acquisition device. A two-dimensional motion tracking algorithm is used to monitor the displacement of the pelvic floor muscles. The muscle displacement field is then computed. The parameter, defined as Mpu, which is the tangential displacements of one interested point near pubis shows good correlation with clinical measurement parameter (LBP) (r = -0.93, P < 0.05). The continuous control ability of the pelvic muscles is further evaluated by measuring the average maintaining time of the maximal contraction force and the muscle thickness during this maintaining period. Both of them are well correlated with the clinical grading results of prolapse. It is concluded that the ultrasound measurements of tissue motions and biomechanics are of great value for the clinical pelvic floor prolapse diagnosis.