Laparoscopy is the gold standard in the diagnosis of endometriosis. It is the most sensitive examination, with the ability to identify both deeply infiltrating disease and superficial peritoneal lesions. Clinical examination has a poor predictive value for determining the site and extent of disease and additional information in the pre-operative setting will aid patient information, the consent process and surgical planning, especially where bowel surgery may be required. Ultrasound has the capacity to establish the site of the lesion and assessing its extent possibly assisting with direction of surgical technique and planning.
Ovarian endometriomas can be detected on greyscale transvaginal sonography with a sensitivity of 80% (range 64-89%) and specificity of 90% (range 85-100%). The recognition of ovarian involvement by scanning has been demonstrated to be associated with a 99% chance of other deeply invasive disease in the pelvis.
Both transvaginal and transrecal sonography have been used to diagnose disease in the colon and rectum and its presence can be detected with a sensitivity of 90% (85-100% and a specificity of 88% (82-100%). Deeply invasive disease of the uterosacral ligaments is more difficult to detect sonographically (sensitivity of 71-75 %), although its specificity is considerably higher. Vaginal disease is poorly imaged with ultrasound, with a sensitivity between 25 and 29%, although clinical examination is much more reliable for this aspect of deeply invasive disease of the pelvis.
In summary, the addition of sonographic imaging aids considerably for women with deeply invasive disease of the pelvis, since clinical examination alone provides limited ability to determine the site and extent of disease, especially of the ovaries and gastro-intestinal tract. It is a very useful adjunct to clinical examination and is likely to provide a more accurate assessment to the patient of disease extent and the appropriateness of medical, surgical or assisted reproductive technology interventions. The duration of surgery and the need for specialist input from colo-rectal colleagues and the likelihood of significant clinical outcomes (e.g. colostomy) being required can also be discussed with the patient pre-operatively.