# Magnetic Resonance Roadmap in Detecting and Staging Endometiosis: Usual and Unusual Localizations
## 7 Post-Operative Imaging  
Treatment approaches have to be assessed based on multiple factors. Medical therapy is definitely the first-line therapeutic option for patients with manageable pelvic pain and no desire for immediate pregnancy. It consists of combined oral contraceptives, progesterone or estrogen. In the second line, analogs of GnRH can be used. Medical therapy also includes specific pain medications and can often be a combination of drugs [87]. On the other hand, surgery is necessary in case of symptoms not controlled by medical therapy, massive or growing endometriosis, infertility or important involvement of the abdominal organs with high risk for systemic complications. In women with infertility, the opportunity for assisted reproduction technologies before performing surgery should be considered [88]. The approach is generally laparoscopic with minimally invasive techniques, and it consists of the identification and removal of endometri foci and the restoration of the correct pelvic anatomy [35]. The laparotomy approach is reserved for rare cases where lesions are much more extensive. Post-operative MRI can be useful both to document the success of the surgery with normal post-operative findings and to highlight some parabynsiological conditions such as the presence of fibrosis, adhesions or even alterations of the pelvic anatomy that can contribute to symptoms or disorders. It is also possible that a CT scan or MRI may be necessary to assess post-operative complications or the presence of recurring or residual disease [89]. In this paragraph, we will explore the main signs in post-operative imaging in order to provide the radiologist with an indication to evaluate MRIs of women with extensive and complex endometriosis undergoing surgery (Figures 15 and 16). Figure 14: Localization of the left sciatic nerve and para-uterine endometriic nodule in a 43-year-olf female with a previously diagnosed endometriosis and surgery approach, accepted at the emergency department for reported left lumbar pain, which radiates to the left side and is associated with episodes of vomiting. (**A**) Coronal T2 WI. Involvement of peripheral nerve plexuses of the pelvic region (sciatic nerve) appearing as a hypointense plaque (white arrow); (**B**) Coronal fat-suppressed T1 WI. The lesion shows small nematic foci (white arrow); (**C**) Axial T2 WI. Para-uterine endometriic nodule (white dotted arrow) shows variable intensity ranging from low intensity (referred to as shading) to intermediate or high intensity; (**D**) Axial T1 WI. Para-uterine endometriic nodule with hyperintense signal (white dotted arrow). According to [PERSON] et al., the first pelvic post-operative MRI should be performed after 6 months. It could be anticipated in selected cases of women who are undergoing medically assisted procreation for infertility [89; 90]. One of the main challenges for the radiologist is to make a correct differential diagnosis between post-operative fibrosis and recurring/residual disease. MRI can highlight the difference between these two conditions: fibrotic scars or plaques appear as bands of hypointensity on T2 WI, without areas of cystic degeneration, blood foci (hyperintense in T1 WI) or even nodular thickenings that are otherwise typical signs of endometric lesions [89]. Figure 16: Localization of endometriosis in the left parametrium and ureteral stenosis in 49-year-old female who underwent supracervical hysterectomy, bilateral salpingectomy and mild vaginal bleeding and abdominal pain. (**A**) Axial T2 WI; (**B**) Sagittal T2 WI. Endometric localization of the left parametrium (white arrow), with irregular margins and heterogeneous signal intensity. Tractions towards the sigmoid colon, left pararecal fascia, anterior pelvic peritoneal reflection and adnexa. Ureteral stenosis caused by the parametrial plaque (dotted arrows in (**B**)). (**C**) Axial T2 WI; (**D**) Axial fat-suppressed T1 WI. Endometric nodule of the left pelvic wall (white arrow).