Presentation Number: 188 3-D IMAGING AND QUANTIFICATION OF VAGINAL TISSUE ELASTICITY UNDER NORMAL AND PROLAPSE CONDITIONS

Objective: The objective of this study is to assess the clinical suitability of a new approach for 3-D imaging and quantification of vaginal tissue elasticity under normal and prolapse conditions. Background: Changes in the elasticity of vaginal walls, connective support tissues and muscles are thought to be significant factors in the development of pelvic organ prolapse. To date, there is no standardized, non-invasive, reproducible tool to accurately assess the circumferential elastic properties of the vagina. In prior studies, we clinically tested the Vaginal Tactile Imager (VTI) which allows for tissue imaging at specified locations in vagina and assessment of tissue elasticity by means of introduced elasticity index [1]. VTI is based on principles similar to those of manual palpation. It is capable of visualizing tissue mechanical structure by measuring surface stress patterns under tissue deformation using a pressure sensor array [2]. Methods: Thirty one women were enrolled in the study (clinical trials identifier NCT01111916). The study subjects included 18 women with normal pelvic support and 13 women with pelvic organ prolapse (Stage I-III). Average age was 60±17 (range 28–90). The transvaginal probe comprised of 128 pressure sensors and a 3-D motion tracking sensor covered by disposable sheath used with ultrasound lubricant. The images were obtained and recorded in an office setting at the time of routine vaginal examination. Three orthogonal projections of 3-D vaginal tactile image with VTI probe location are observed by operator in real time. The Pelvic Organ Prolapse Quantification (POP-Q) system for prolapse classification. Tissue elasticity (Young’s modulus) was calculated from spatial gradients in resulting 3-D tactile image. Each VTI examination took 3–5 min. Results: All 31 women were successfully examined with the VTI device. 3-D images of the vagina were recorded and stored. We found substantial differences in anatomy and tissue elasticity between normal and prolapse conditions. Average values for tissue elasticity for anterior and posterior compartments for normal conditions were 7.2±4.9 kPa and 6.6±4.0 kPa respectively. For Stage III prolapse the average values for tissue elasticity for anterior and posterior compartments were 1.6±0.9 kPa and 1.7± 1.1 kPa respectively. Figure 1 and Figure 2 present examples of examination results for normal and prolapse conditions. The patients were asked to assess comfort level of the VTI examination relative to manual palpation: 77% said that VTI procedure is the same, 20% less comfortable, and 3% more comfortable. No adverse events were reported. Conclusions: Our findings suggest that VTI is suitable for 3-D imaging of the vagina and provides quantitative assessment of vaginal tissue elasticity. VTI offers insight into individual variations in biomechanical properties of vaginal tissues to further our understanding of prolapse and optimize surgical repairs. The work was supported by the National Institute on Aging, USA, Grant 1 R43 AG034714-01 References: 1. IEEE Trans. Biomed. Eng. 2010; 57(7):1736–44. 2. Int. J. Med. Inf. 1998; 49: 195–216.