**3. Diagnostic evaluation of endometriosis**

Although the definitive diagnosis of endometriosis requires surgical intervention, preferably through videolaparoscopy, several findings in physical, imaging, and laboratory tests can already predict, with a high degree of reliability, that the patient has endometriosis. To date, no biochemical marker can be considered as an endometriosis endpoint, but Ca-125, when collected on the first or second day of the menstrual cycle, may be useful for the diagnosis of advanced stage endometriosis when the values are higher than 100 IU/mL [3]. Although normal

concentrations do not exclude the disease, cases with elevated preoperative levels may aid in patient follow-up and clinical suspicion of recurrence of endometriosis. More recently, some cytokines have been studied as new nonsurgical endometriosis markers. Interleukin-6 (IL-6) appears to perform better than other cytokines in discriminating patients with endometriosis [4]. The first imaging test to be applied to the patient with a history and physical examination suggestive of endometriosis is transvaginal pelvic ultrasound, preferably with intestinal preparation. A study by Abrão et al. [5], evaluating the accuracy of this test, demonstrated a sensitivity of 94% and a specificity of 98% in the identification of foci of deep endometriosis. If the test is normal, the patient may not have endometriosis or have noninfiltrative initial disease. On the other hand, if the test is conclusive for ovarian endometriosis, rectovaginal septum or rectosigmoid, or urinary tract, treatment may be indicated without additional imaging tests. For evaluation of endometriomas larger than 2 cm, transvaginal ultrasonography is an efficient method, according to Moore et al. [6]. The presence of ovarian masses with a doubtful diagnostic hypothesis can be better evaluated with magnetic resonance imaging (MRI). Changes suggestive of rectovaginal septum disease, uterosacral, or rectosigmoid ligaments may be confirmed by rectal echoendoscopy or MRI. Rectal echoendoscopy allows the identification of the distance between the lesion and the rectal lumen as well as extrinsic compressions and submucosal lesions of the rectum [7]. MRI also allows the identification of deep disease with invasion of the intestinal tract, but it does not make it possible to specify the intestinal layer affected by the lesion [8]. Transvaginal ultrasonography for the diagnosis of bladder endometriosis has been reported as an effective method, with sensitivity of 71.4% and specificity of 100% [9]. Ultrasonography suggestive of bladder or ureteral endometriosis can be complemented with excretory urography, which may show ureteral narrowing. Uro-resonance can be used as an alternative method to excretory urography for evaluation of renal collecting system dilatations. Although the available imaging exams presented good accuracy in the diagnosis of endometriosis, laparoscopy with lesion biopsy for anatomopathological analysis is still the gold standard in the diagnosis of endometriosis.
