Vaginal microcirculation: Non-invasive anatomical examination of the micro-vessel architecture, tortuosity and capillary density.

Aim: To describe the vaginal microcirculatory architecture and capillary density parameters using sidestream dark-field imaging (SDFI), and determine feasibility and reliability of this method.

Methods: In nine healthy female volunteers SDFI measurements were performed at two different time points in the luteal phase of the menstrual cycle. Non-invasive tissue micro-angioarchitecture and vaginal capillary density measurements were assessed independently by two observers. Agreement was expressed with mean differences between the measurements of both observers and the limits of agreement. Inter- and intra-observer agreement was quantified with the intra-class correlation coefficient (ICC).

Results: Vaginal microcirculatory assessment with the SDFI device was easy in use, painless and well accepted by the participants. Morphologically, the vaginal microcirculation revealed an array of single hairpin-shaped capillary loops distributed homogeneously across an imaged tissue segment. The intra-observer assessment of the capillary density measurements (comparing two measurement time points of one observer) showed good agreement with an ICC ranging from 0.62 to 0.85. The inter-observer assessments of the capillary density measurements (comparing assessments of two observers at one time point) revealed very good agreement, with small differences between observers and an ICC of more than 0.9.

Conclusions: This is the first report on both microcirculatory architecture and quantitative microcirculatory parameters of the vagina with the use of SDFI. Micro-vessels of the vagina show a recognizable pattern in our study population of young, healthy women. SDFI gives a reproducible assessment of the vaginal microcirculation offering the researcher a wide field of applications.