Endometriosis is a common cause of chronic pelvic pain, dysmenorrhea and infertility. Although 6–10% of women of child bearing age are affected by the disease, diagnosis is often delayed and treatment can be challenging. The impact on fertility is clear when we look at the higher prevalence of endometriosis in women with fertility problems (up to 47% according to some sources). Many theories on the pathophysiology exist, including the implantation of eutopic endometrium from retrograde menstruation, the metaplasia of pluripotent cells of the mesothelium, and thirdly the theory of müllerianosis: misplaced endometrial tissue at the time of fetal organogenesis developing into endometriosis. Endometriotic cells have the ability to embolize to distant locations, including the diaphragm, pleural cavity and even, on rare occasions, the brain. In doing so, this benign entity behaves much like a cancer. Malignant transformation of endometriomas can occur, and these patients have a fourfold increased risk of ovarian cancer. Endometriosis is a multifactorial disease, with a strong familial component but clear impact of environmental and other factors as well.
Treatment of endometriosis can be very challenging and depends on the goal: is it reduction of (pain) symptoms? Is it to tackle infertility? Or is it a combination of problems that needs addressing? The need for a multidisciplinary approach becomes clear at this point, discussing the extent of disease, the expectations of the patient, the goals of treatment and the best way to reach these goals. The Golden Standard of diagnosis in endometriosis remains diagnostic laparoscopy with histologic confirmation. However, preoperative surgery planning can be aided by the use of several imaging techniques.
Computed tomography (CT) has no value in the initial work-up of endometriosis, lacking sensitivity and specificity. It does however play a role in the evaluation of postoperative complications.
Transvaginal ultrasound (TVUS) is relatively cheap and readily available. However, it’s sensitivity and specificity are very dependent on operator experience. The lack of anatomical landmarks for surgeons to recognize on these images explains why they are often reluctant to rely on this imaging technique alone. TVUS is difficult, if not impossible to apply in a virgo patient. Transabdominal ultrasound however is clearly inferior and should not be used as a substitute instead. Most often performed by gynecologists, this presentation will not go into further detail about this technique.
Magnetic resonance imaging (MRI) may be costlier and not so readily available, but it has the clear advantage of providing a more readily understandable anatomical image of the pelvis, with the additional possibility of second reading at a later time to look for additional findings. The larger field of view (FOV) of MRI as compared to TVUS allows for better evaluation of more distant locations. High resolution T2-weighted sequences with a small FOV in several planes form the basis of any endometriosis protocol. Endometrioma of the ovary is readily recognizable as a cystic lesion with T2 shading (Figure 1). Endometriosis implants most often present as T2-hypo-intense spiculated lesions that cause adhesions (Figure 2). Invasion through the serosa of the bladder or bowel wall and frank transmucosal growth is readily demonstrable (Figure 3). T1-weighted imaging can aid in the detection of hemorrhagic products (Figure 1). The addition of Gadolinium enhanced and diffusion weighted sequences should be considered when malignant transformation or concurrent malignancy of other origin is suspected.
The author has no competing interests to declare.