Accuracy of endovaginal sonography for the detection of fallopian tube blockage

The patency of 814 fallopian tubes in 414 patients was evaluated by endovaginal sonography immediately prior to hysterosalpingography. In the 659 fallopian tubes that were normal with free spillage, endovaginal sonography did not reveal any tubal or peritubal abnormality (specificity 100%). Of the 64 fallopian tubes with definite hydrosalpinx on hysterosalpingography, only 22 were detected on endovaginal sonography (sensitivity 34%). Four of 57 (7%) fallopian tubes with definite proximal blockage on the hysterosalpingogram showed hydrosalpinx on the same side on endovaginal sonography, indicating the association of proximal and distal tubal blockages in a small group of patients with blocked fallopian tubes. This combination can only be detected by the addition of endovaginal sonography to hysterosalpingography. Ten of 11 (91%) hydrosalpinges in seven patients who underwent endovaginal sonography immediately after hysterosalpingography were detected by ultrasonography. Only two of these had been visible on pre-hysterosalpingography endovaginal sonograms. This would indicate that the poor sensitivity of endovaginal sonography for diagnosing hydrosalpinx is at least partly due to its lack of distention. We conclude that an abnormal endovaginal sonogram is highly predictive of the presence of a blocked tube, but endovaginal sonography has a poor sensitivity for the diagnosis of a hydrosalpinx detectable by hysterosalpingography. Endovaginal sonography would be useful to detect a combination of proximal and distal blockage in a subgroup of patients with tubal blockage.