A feasibility study of three‐dimensional ultrasound imaging of the vagina under distension

• Published in: Medical physics (Lancaster) 2024-01, Vol.51 (1), p.80-92
• Main Authors: Zhang, Shufei, Blokker, Alexandra M., Borazjani, Ali, Hong, Christopher X., Chaikof, Michael, Giroux, Maria, Edell, Humara, Eltahawi, Ahmed, Ameri, Golafsoun, McDermott, Colleen D.
• Format: Article
• Language: English
• Subjects: biomechanics; pelvic organ prolapse; ultrasound
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1002/mp.16810

Background The distension properties of the vagina are critical to its function including support of surrounding organs, childbirth, and intercourse. It could be altered by many pathophysiological processes like pregnancy, radiotherapy, and reconstruction surgery. However, there are no clinically available diagnostic tools capable of quantifying the distension properties of the vagina. Purpose A proof‐of‐concept study was designed to assess the feasibility of a novel three‐dimensional (3D) ultrasound imaging technique that allows quantitative evaluation of the vagina under distension. Methods Patients with symptomatic pelvic organ prolapse (POP) were recruited for the study. An ultrathin, oversized bag was inserted into the vagina and filled with water using a modified urodynamics system. The instilled water volume and intravaginal pressure were continuously recorded. At maximum vaginal capacity, 3D transintroital ultrasound of the distended vagina and surrounding pelvic structures was performed. Exams were performed in duplicate for each patient, two hours apart (round A and round B). Following the development of a 3D surface model of the distended vagina from each scan, several measurements were obtained, including cross‐sectional area, anteroposterior (AP) length and lateral width in the plane of minimum hiatal dimensions (PMHD), AP and lateral diameter at the pubic symphysis (PS) level, maximum and minimum diameter, and maximum vertical length. To assess repeatability between measurements in two rounds, the coefficient of variation (CV) and the intraclass correlation coefficient (ICC) were calculated for each measurement. Correlations between physical measurements including the pelvic organ prolapse quantification (POP‐Q) system and vaginal diameter measurements, and obtained metrics were also assessed. Results Sixteen patients with POP (average age 69 years) completed both rounds of imaging. There was sufficient echogenicity on 3D transintroital ultrasound of the distended vaginal wall to establish boundaries for 3D surface models of the vagina. Overall, all metrics had good or excellent reliability (ICC = 0.77–0.93, p