Three-dimensional ultrasound inversion rendering technique facilitates the diagnosis of hydrosalpinx.

Purpose: To test the utility of three-dimensional (3D) ultrasound (US) inversion rendering technique in the evaluation of fluid-distended fallopian tubes.

Methods: Fifty-two patients with fluid-filled adnexal masses suspected of being abnormal fallopian tubes were scanned by two-dimensional and 3D transvaginal ultrasound (TVUS). Six patients had bilateral disease. The acquired volumes were then "inverted" to display a cast-like appearance of the fluid-filled structures. The ipsilateral ovaries were identified in all patients. Five patients had acute tubal disease.

Results: Fifty-two of the 58 inversion renderings yielded acceptable images of hydrosalpinges. Only in four patients were the two-dimensional images more informative than the 3D-rendered and inverted views. In nine patients adjacent corpora lutea, ovarian cysts, and follicles within normal ovaries were also identified, but appeared separate from the fluid-filled tubes. The tubes in the patients with acute disease were all successfully inverted.

Conclusions: The 3D inversion technique is a simple and effective way to render fluid-filled spaces, which may be tortuous and follow various directions. The rendered images increased the confidence in diagnosing hydrosalpinx.