Transvaginal ultrasonography of rectosigmoid endometriosis: interobserver variation of lesion size

This study evaluates the interobserver variation of transvaginal ultrasonographic measurements of the size of deep infiltrating endometriosis lesions in the rectosigmoid wall performed by an experienced and a less experienced sonographer. Fifteen outpatient women were seen for a gynecologic examination and 24 women were seen with rectosigmoid endometriosis. Transvaginal ultrasonography was performed independently by two observers with a focus on the presence and size of rectosigmoid endometriosis. The senior observer had several years of experience, whereas the junior observer was a medical student with no prior experience in transvaginal ultrasonography. The findings of the two observers were identical concerning the identification of rectosigmoid endometriosis. The probability of differences in size within 30% of the mean was 0.81, 0.63 and 0.61 for length, width and depth, respectively. Our data suggest that fair skills in this technique can be acquired by inexperienced examiners within a short period of time.