Visualization of Pelvic Floor Reflexes
Principal Investigator: CHRISTOS EURIPIDES CONSTANTINOU
Affiliation: Stanford University
Abstract: Female urinary incontinence has been recently termed a "silent epidemic", requiring systematic attention and a multidisciplinary approach towards economically ameliorating its impact. In this study we examine the role of the pelvic floor (PF) in maintaining urinary continence by evaluating the dynamics produced during voluntary and reflex activation. As a result of preparatory work just completed under an R21 study we were able to develop the technology and procedures to attempt to undertake the proposed evaluation as an R01 study. Enabling our approach is the development of criteria and unique new parameters that define the kinematics of PF function. Principal among these parameters, and in addition to the mechanical closure forces are displacement, velocity, acceleration and the trajectory of pelvic floor landmarks. Objectives are to facilitate the visualization of these parameters using a graphical user interface to test the hypothesis that continent older women will present different visualization values than older women with stress incontinence. Movement detection, including motion tracking algorithms and segmentation algorithms will be developed to acquire new parameters of trajectory, displacement, velocity and acceleration, of pelvic structures during different maneuvers. Parameters will be derived from imaging of trans-perineal scanning from asymptomatic volunteers as well as patients presenting with relevant pathology. Additional software innovation in the analysis of these parameters is the ability to define the timing sequences associated with pelvic floor responses. Preliminary observations suggest that timing of response are a significant factor separating the continent from the incontinent subjects. Consequent to evidence generated so far we propose to consider the hypothesis that reflex pelvic floor responses prevent stress urinary incontinence during fast and stressful maneuvers such as coughing are age and parity dependent. Before generalizing this hypothesis we propose to first obtain evidence that spans the age and parity. On the basis of data obtained from ultrasound imaging, we propose to develop a model to simulate the control systems involved in maintaining continence by introducing the Artificial Neural Network (ANN) approach for analysis of the data. ANN will be trained by adjusting the weights of the connections using different algorithms to solve problems including classification and pattern identification. Modified Specific Aim Sections The function of the female Pelvic Floor (PF), which encompasses Pelvic Floor Muscles (PFM), bladder and urethral support, constitutes a very important element in addressing the problem of female Urinary Incontinence (UI). Perineal ultrasound imaging is commonly used in the clinical evaluation of PF function related to UI. However, in real time ultrasound imaging, the diagnostically important information of the dynamic response of the PF cannot be assimilated and quantified by the observer during the scanning process. The trajectories and the timing of the movement of the PF tissues, which may be more important than the amplitudes in the mechanism of female urinary continence, are usually ignored. Our preliminary studies suggest that the structural and functional changes of the PF in women with Stress Urinary Incontinence (SUI) can be highlighted by analyzing the activities of an anatomical triangle comprising of the Urethra-Vesical Junction (UVJ), Ano-Rectal Angle (ARA) and Symphysis Pubis (SP). We propose to develop a software package of 2-D ultrasound image processing to analyze both the static and dynamic responses of the UVJ-ARA-SP triangle and to further disclose its physiological and clinical significance in the mechanism of urinary continence. The proposed study includes the following specific aims: (1) Quantitatively analyze the static characters of the UVJ-ARA-SP triangle and relate to urethral closure pressures and their transmission characteristics. Correlate these with reference to age, physical examination and parity in pre and postmenopausal women who are continent or report SUI. " Graphical user interfaces will be developed to acquire the UVJ-ARA-SP triangle and analyze its static parameters including the area, the three internal angles and the lengths of the three sides. (2) Quantitatively visualize the dynamic characters of the UVJ-ARA-SP triangle. " Different methods of movement detection, including motion tracking algorithms and segmentation algorithms will be developed to acquire new kinematic parameters, including trajectory, displacement, velocity and acceleration, of the UVJ and ARA. " The changes of the parameters of the UVJ-ARA-SP triangle (area, internal angles and lengths of sides) in different maneuvers will be analyzed. " 2D animation will be applied to enhance the ultrasound imaging and highlight the timing of the movement and deformation of the UVJ-ARA-SP triangle in fast and stressful maneuvers, which are important for understanding the neuromuscular control mechanisms in urinary continence. (3) Quantitatively visualize the dynamic profiles of the urethra and ARA in the UVJ-ARA-SP triangle " The visualization of the movement profile of the urethra will be performed to highlight the opening and closure mechanism of the urethra. " The visualization of the movement profile of the ARA will be performed to highlight the mechanisms and functions of the PFM activities. " 2D animation will be applied to enhance the ultrasound imaging and highlight the timing of the movement and deformation of the urethra and ARA in different maneuvers. (4) Classification of PF functions using artificial neural networks (ANN) " ANN for the classification of healthy subjects and SUI patients using the static and dynamic parameters derived from the quantitative measurement of the UVJ-ARA-SP triangle. " ANN to enable evaluation of PF functions using the dynamic trajectories of the UVJ-ARA-SP triangle. Clinical experiments will be performed for the comparison of the static and dynamic characters of the UVJ-ARA-SP triangle of symptomatic subjects and patients with SUI in different maneuvers. To realize these objectives, we hypothesize that continent older women will present higher pelvic floor strength values than older women with stress incontinence in the following parameters: resting PFM strength to voluntary contraction tasks for maximum strength and speed and latency of force development. These values will be higher in age matched nulliparous women. Correlatively we hypothesize that continent older women will present different visualization values in the UVJ-ARA-SP triangle than older women with stress incontinence in the following new parameters obtained from ultrasound imaging: magnitude, direction, velocity, and displacement of the, bladder neck than continent women. Bladder neck approximation will be lower at rest, during PFM contraction and Valsalva maneuvers in continent women. NOTE: We propose to sustain original effort use the originally proposed number of subjects and collect essential data. As indicated above we will NOT carry out the programming for the 2D animation portion of the proposal but instead ensure that data are coded appropriately and be made available.
Funding Period: ----------------2009 - ---------------2011-
more information: NIH RePORT