The Benign Side of the Abdominal Wall: A Pictorial Review of Non-Neoplastic Diseases

Role of computed tomography in imaging of endometriosis

Endometriosis is a chronic systemic disease characterized by the presence of endometrium-like glands and/or stroma outside the uterus, usually with an associated inflammatory process. It affects around 5-10% of women worldwide, with chronic pelvic pain and infertility being the predominant symptoms. Although suspected clinically, transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) are the primary imaging tools for diagnosing pelvic endometriosis, as well as helping in pre-surgical mapping. Computed tomography (CT) is not the preferred imaging modality for detection or depiction of disease extent. However, CT of the abdomen and pelvis is often performed as the initial imaging test in women presenting with acute or non-specific abdominal/ pelvic pain. CT features of endometriosis can vary depending on the organ affected, and the correct diagnosis is often not suspected due to its nonspecific CT appearance and overlap with other pathologies. Ovarian endometriomas (OMAs), the most recognized phenotype of endometriosis, may appear as hyperdense adnexal masses either in the expected location of the ovaries or positioned posterior to the uterus. Endometriomas may rupture, presenting with hemoperitoneum. The uterus may be distorted and acutely retroflexed from deep endometriosis along the posterior uterine surface. The bowel can be affected by endometriosis, especially the rectosigmoid colon, presenting as enhancing soft tissue bridging from the posterior uterine surface to the anterior rectal wall. Small bowel involvement may present with recurrent small bowel obstructions. Involvement of the urinary system may present with ureteral obstruction or a bladder wall mass. Given such varied appearances, a high degree of clinical suspicion and knowledge of CT features suggestive of endometriosis is required to facilitate an early diagnosis. This review paper therefore describes the imaging findings of endometriosis that can be recognized on an abdominopelvic CT, with the goal of decreasing the existing delay to accurate diagnosis and improving long term patient outcomes.

Off the wall: incidental paraspinal and pelvic muscle pathology on abdominopelvic imaging

As the use of cross-sectional abdominal and pelvic imaging has increased exponentially in the past several decades, incidental musculoskeletal findings have become commonplace. These are often unrelated to the indication for the examination and are frequently referred to as the "radiologist's blind spot" on these studies. The differential diagnosis for abnormalities of the paraspinal and pelvic musculature is, in many cases, quite different from the anterior abdominal wall muscles. Furthermore, due to their relatively deep location, pathology involving the former muscle groups is more likely to be clinically occult, often presenting only incidentally when the patient undergoes cross-sectional imaging. Effective treatment of diseases of these muscles is dependent on adherence to a diverse set of diagnostic and treatment algorithms. The purpose of this review article is to familiarize the radiologist with the unique pathology of these often-overlooked muscles of the abdomen and pelvis.