Quantitative analysis of uterine peristalsis in women with adenomyosis using optical flow for motion quantification.

RESEARCH QUESTION: Do women with adenomyosis have altered uterine peristalsis, and can an objective and reproducible tool be developed to quantify uterine peristalsis on transvaginal sonography (TVS)?

DESIGN

Prospective observational cohort study in women with moderate to severe adenomyosis (n = 26) or a normal uterus (n = 40) undergoing TVS during assisted conception. TVS recordings (n = 143) were conducted at baseline, day 6-10 of ovarian stimulation and day of embryo transfer by operator A, and then repeated by operator A, B or C. Image data were stored offline for optical flow analysis. Pixel-level displacements for points at the endometrial--myometrial junction were used to compute peristalsis frequency and amplitude by fitting to the two-dimensional wave equation. Fit error was taken as a measure of wave coordination. Inter-class correlation coefficient (ICC) was calculated to assess inter- and intra-observer agreement.

RESULTS

Women with adenomyosis had a significantly higher fit error at all time points during the IVF cycle (baseline: + 0.725, P < 0.001; ovarian stimulation: + 0.612, P = 0.004; embryo transfer: + 0.627, P < 0.001), indicating lower uterine peristalsis coordination compared with women with a normal uterus. Inter- and intra-observer agreement for each wave feature (frequency, amplitude and coordination of uterine peristalsis and myometrial contractility) was found to be moderate to good (intra-observer ICC: 0.62-0.75, inter-observer ICC: 0.58-0.79).

CONCLUSION

An objective and reproducible measuring tool is proposed to quantify uterine peristalsis using TVS, with potential for wide application across assisted conception and gynaecology settings.