A model established for predicting natural pregnancy possibility based on the imaging characteristics of 4-dimensional hysterosalpingo-contrast sonography.

Abstract

The incidence of infertility is increasing, more than 30% of them having related abnormal tubal patency. Four-dimensional (4D) hysterosalpingo-contrast sonography (HyCoSy) overcomes the shortcomings of 3D HyCoSy in the diagnosis of tubal patency, showing high specificity and accuracy. In addition, 4D HyCoSy discards iodine allergy and X-ray radiation and possesses easy-operating, contributing to good acceptance in clinical practice. However, there is no research to explore the imaging standards related to the possibility of natural pregnancy after 4D HyCoSy. If a predictive model of postoperative natural pregnancy was established using the analysis of clinical data combined with imaging characteristics of 4D HyCoSy of patients with tubal factor infertility, clinical decision-making can be wisely guided in the future. This study aims to establish a predictive model of natural pregnancy after 4D HyCoSy based on clinical data and imaging characteristics of patients with tubal factor in fertility. A retrospective study was conducted for patients who were diagnosed with tubal factor infertility in Hunan Guangxiu Hospital from February 2017 to May 2018. The patients ought to possess complete 4D HyCoSy imaging data and at least one-side-unobstructed fallopian tube. General clinical data and imaging data were collected. Pregnancy outcome was followed up till 3 months after 4D HyCoSy. According to pregnancy outcome, patients were divided into a pregnancy group and a non-pregnancy group. Binary logistic regression was used to analyze the correlation between various variables and natural pregnancy after 4D HyCoSy. The variables with significant difference (P<0.05) in single-factor logistic regression were included in the natural pregnancy probability prediction model. The classification accuracy was further verified with 10-fold cross-validation. A total of 1 085 patients with clinically suspected tubal factor infertility who met the requirements and followed the doctors' prescription were collected. Clinical characteristics (age and duration of infertility) and 4D HyCoSy imaging characteristics (thickness of endometrium from the 3rd to the 7th day after the end of menstruation, visualization of the left fallopian tube, the diffusion of contrast agent around the left ovary, and the diffusion of contrast agent around the right ovary) were independent predictors for natural pregnancy 3 months after 4D HyCoSy. A natural pregnancy probability prediction model was established with the area under the curve (AUC) verified by the 10-fold cross-validation all greater than 0.75, and the best AUC was 0.868. The Q value obtained by the prediction model was the probability of natural pregnancy, and the cutoff value was 0.5. When the Q value was greater than 0.5, it was recommended to attempt natural pregnancy for 3 months, and when the Q value was less than 0.5, in vitro fertilization was adviced. A predictive model for the evaluating probability of natural pregnancy in women with tubal factor infertility after 4D HyCoSy is successfully established based on the analysis for clinical data and imaging characteristics. This model shows a great potential in assisting clinical decision making.