MR staging of pelvic endometriosis: role of fat-suppression T1-weighted images.
We examined whether MR can determine the stage of endometriosis according to the scoring system established and revised by the American Fertility Society (r-AFS), a system which is widely used by gynecologists. We also studied the utility of fat suppression T1-weighted images in improving accuracy. Seventeen patients with endometriosis examined by conventional MR were included in this study. All the patients had surgically proved stage III or IV disease. We determined the stage by MR using the following criteria according to the r-AFS system: adnexal masses without normal ovarian tissue were considered deep ovarian lesions, while those with normal tissue were considered superficial. A lack of fat between the lesion and surrounding structures was considered a dense adhesion, and hyperintense spots were considered peritoneal implants. The MR scores of patients with and without fat suppression were correlated with the surgical scores. MR staging corresponded to surgical staging in 15 of the 17 patients. In eight patients, peritoneal implants of less than 1.5 cm were depicted only by fat-suppression images. However, these lesions did not change the score significantly. MR imaging could determine the stage in advanced endometriosis. Fat-suppression could highlight smaller implants. These tiny lesions had little clinical meaning in these advanced cases; however, the clinical value of this technique should be evaluated in milder disease.