E5209. Deep Infiltrative Pelvic Endometriosis: MRI-Based Review
  1. Maitena Blanco; No Affiliation
  2. Ivonne Loaiza Pacheco; No Affiliation
  3. Manuela Laguna Kirof; No Affiliation
  4. Nebil Larrañaga; No Affiliation
Endometriosis is characterized by the presence of endometrial tissue outside the uterine cavity. Morphologically, endometriosis can be classified as ovarian endometrioma, superficial endometriosis, and deep infiltrating endometriosis. Deep endometriosis is defined as endometriosis infiltrating more than 5 cm into the peritoneum, and it is classified into anterior, middle, and posterior. The noninvasive nature of MRI allows for detailed visualization of the extent and location of endometriotic lesions, assisting clinicians in tailoring effective treatment strategies.

Educational Goals / Teaching Points
Identify the imaging findings of deep endometriosis through MRI. Identify characteristic lesion locations in cases of deep endometriosis. Emphasize the significance of MRI in diagnosing deep pelvic endometriosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Based on anatomical distribution, pelvic endometriosis is classified into anterior, middle, and posterior compartment endometriosis. To better distinguish the spectrum of clinical presentations, it's important to recognize superficial endometriotic implants, which are the first macroscopically recognizable lesions on the surface of the pelvic organs. Ovarian endometrioma is the most common site of endometriosis and is characterized as a pseudocyst with hemorrhagic content. It's often bilateral and multilocular. Finally, deep infiltrating endometriosis involves subperitoneal invasion by an endometriotic lesion that exceeds 5 cm in depth. On MRI, deep pelvic endometriosis lesions appear with poorly defined borders, an infiltrating appearance, producing retraction of organs and neighboring structures, with low or intermediate signal on T1- and T2-weighted sequences that enhance after contrast administration. The most frequently affected areas in deep pelvic endometriosis are the Douglas's pouch, uterine torus, intestinal wall, and bladder. For a proper imaging analysis and diagnosis, a systematic assessment of the position of the uterus and its contours, myometrial signal, junctional zone, and location of adnexa is necessary.

A systematic analysis is of utmost importance when it comes to the MRI diagnosis of deep endometriosis. Such a methodical analysis not only facilitates precise diagnosis but also informs therapeutic decisions, ensuring that tailored treatment plans can be devised to address the condition effectively in women of reproductive age.