Objective: To evaluate the accuracy of three-dimension (3D) sonohysterography in detecting intrauterine lesions, and to compare it with two-dimension (2D) transvaginal ultrasound, three-dimension (3D) transvaginal ultrasound and two-dimension (2D) sonohysterography.Design: Prospective study in a university teaching hospital.Materials/Methods: 209 patients suspected to harbour an intrauterine lesion on hysterosalpingography and 2D vaginal ultrasound were included in the study. They subsequently underwent a 3D ultrasound, 2D and 3D sonohysterography (SHG). 95 patients were found to have a lesion distorting the endometrium on the 3D SHG. The 3D SHG findings were correlated with the 2D ultrasound, the 3D ultrasound, and the 2D sonohysterographic findings. In 51 patients, the 3D SHG findings were correlated with hysteroscopic examination.Results: Out of the 95 patients with an intrauterine lesion, 48 had polyp, 35 had submucous or intramural myoma, 3 had both polyp and myoma, 4 had a mullerian anomaly, 1 had thick endometrium and 1 had synechiae on the 3D sonohysterography. Three sonohysterographies were inconclusive. The mean age of the patients was 35.7 years (22–46). The reason for investigation was infertility in 188 patients, recurrent pregnancy loss in 12 patients, dysfunctional uterine bleeding associated with infertility in 9 patients. Compared to the 3D SHG results, the sensitivity and specificity of the 2D transvaginal ultrasound is 100% and 13%, 100% and 54% for the 3D ultrasound, and 98% and 100% for the 2D sonohysterography. In the subgroup of patients who had had a hysteroscopic examination, the sensitivity of the 3D SHG was 100%, and the positive predictive value is 94%.Conclusions: Three-dimensional sonohysterography can become a standard procedure in women with intrauterine lesions noted on routine transvaginal ultrasound. It allows precise recognition of the uterine anatomy and localisation of lesions. It could also avoid unnecessary invasive diagnostic procedures as hysteroscopy when interpreted as normal.Supported by: None. Objective: To evaluate the accuracy of three-dimension (3D) sonohysterography in detecting intrauterine lesions, and to compare it with two-dimension (2D) transvaginal ultrasound, three-dimension (3D) transvaginal ultrasound and two-dimension (2D) sonohysterography. Design: Prospective study in a university teaching hospital. Materials/Methods: 209 patients suspected to harbour an intrauterine lesion on hysterosalpingography and 2D vaginal ultrasound were included in the study. They subsequently underwent a 3D ultrasound, 2D and 3D sonohysterography (SHG). 95 patients were found to have a lesion distorting the endometrium on the 3D SHG. The 3D SHG findings were correlated with the 2D ultrasound, the 3D ultrasound, and the 2D sonohysterographic findings. In 51 patients, the 3D SHG findings were correlated with hysteroscopic examination. Results: Out of the 95 patients with an intrauterine lesion, 48 had polyp, 35 had submucous or intramural myoma, 3 had both polyp and myoma, 4 had a mullerian anomaly, 1 had thick endometrium and 1 had synechiae on the 3D sonohysterography. Three sonohysterographies were inconclusive. The mean age of the patients was 35.7 years (22–46). The reason for investigation was infertility in 188 patients, recurrent pregnancy loss in 12 patients, dysfunctional uterine bleeding associated with infertility in 9 patients. Compared to the 3D SHG results, the sensitivity and specificity of the 2D transvaginal ultrasound is 100% and 13%, 100% and 54% for the 3D ultrasound, and 98% and 100% for the 2D sonohysterography. In the subgroup of patients who had had a hysteroscopic examination, the sensitivity of the 3D SHG was 100%, and the positive predictive value is 94%. Conclusions: Three-dimensional sonohysterography can become a standard procedure in women with intrauterine lesions noted on routine transvaginal ultrasound. It allows precise recognition of the uterine anatomy and localisation of lesions. It could also avoid unnecessary invasive diagnostic procedures as hysteroscopy when interpreted as normal. Supported by: None.