To assess the value of abnormal morphologies of the fallopian tubes revealed by four-dimensional hysterosalpingo contrast sonography (4D-HyCoSy) in the diagnosis of fallopian tube patency.

In this retrospective observational study, 52 infertile female patients undergoing 4D-HyCoSy from January 2016 to July 2019 were included. All the patients were followed by laparoscopic and dye hydrotubation (Lap and Dye) within 3 months, and according to the results of Lap and Dye, they were divided into an obstruction group (n=18) and a non-obstruction group (n=34). Eighty-seven patent, partially patent, or distally obstructed fallopian tubes, as revealed by Lap and Dye, were included in the analysis. Abnormal morphologies of the tubes, as revealed by 4D-HyCoSy, were recorded and analyzed. Normal morphologies of the tubes were defined as smooth shape and uniform inner diameter. Abnormal morphologies of the tubes were defined as distortion, stiffness, slenderness (sudden narrow, inner diameter ＜ 0.5×inner diameter nearby), and dilation (sudden dilation, inner diameter ＞ 2×inner diameter nearby). The general data of the patients were compared between different groups using Mann-Whitney U test, Pearson Chi-square test, or Fisher exact test. The correlation between the abnormal morphologies of the tubes and fallopian tube patency degree was analyzed by multinomial logistics regression (including single factor analysis and multi-factor analysis). Each examination was performed by two experienced physicians who had worked for more than 5 years.

There was no significant difference in age, duration of infertility, primary infertility, 2D-ultrasound observations (myomas, endometrial polyps, intrauterine adhesions, and pelvic endometriosis) between the obstruction group and non-obstruction group (P＞0.05). Of the 87 tubes included, 35 were distorted (40.2%), 35 were dilated (40.2%), 40 were slender (46.0%), and 10 were stiff (11.5%). The Chi-square test showed a statistically signi?cant association between fallopian tube patency and distortion, dilation, and slenderness [2 (5.1%) vs 16 (57.1%) vs 17 (85.0%), χ²=18.17, P＜0.001; 5 (12.8%) vs 12 (42.9%) vs 18 (90.0%), χ²=10.76, P=0.005; 7 (17.9%) vs 20 (71.4%) vs 13 (65.0%), χ²=13.67, P=0.001, but no significant association with stiffness (P＞0.05). The influencing factors of distortion and slenderness were independent factors for partial patency (OR=19.884 and 9.721; P=0.001 and 0.001, respectively), while distortion, dilation, and slenderness were independent factors for distal obstruction (OR=41.275, 12.377, and 6.071; P=0.001, 0.015, and 0.040, respectively).

Distortion, dilation, and slenderness are important abnormal morphologies of the fallopian tubes evaluated by 4D-HyCoSy, suggesting that it could provide more accurate diagnostic information for evaluation of fallopian tube patency. Our findings need verification by a large, retrospective observational study.