The Sonographic Spectrum of Pelvic Endometriosis: Pearls, Pitfalls, and Mimics

'That's just the Ovary!' and other cases of mistaken identity on CT of the female pelvis

CT is often the first imaging test in female patients with lower abdominal and pelvic pain because of the wide availability of CT and differential diagnoses that span both gynecologic and gastrointestinal disease. Pathology within the female pelvis may be difficult to diagnose on CT owing to suboptimal delineation of anatomy in comparison to MRI and ultrasound. These challenges are confounded by overlapping imaging features of a wide range of gynecologic entities and can lead to diagnostic dilemmas. High value CT interpretation will direct the clinician to the best next diagnostic step as ultrasound and MRI provide superior soft tissue delineation. Other imaging modalities, laboratory investigations, or tissue sampling may be necessary to definitively characterize indeterminate lesions. In this review, we illustrate various cases of mistaken identity on CT of the female pelvis involving the ovaries, uterus, and peritoneal cavity while highlighting clinical pearls that may aid the radiologist in arriving at the correct diagnosis and avoiding potential pitfalls.

Imaging of Endometriosis: The Role of Ultrasound and Magnetic Resonance

Endometriosis is a chronic gynecological disease characterized by the growth of functional ectopic endometrial glands and stroma outside the uterus. It causes pelvic pain, dysmenorrhea, dyspareunia, or infertility. Diagnosis requires a combination of clinical history, non-invasive and invasive techniques. The aim of the present review was to evaluate the contribution of imaging techniques, mainly transvaginal sonography and magnetic resonance imaging to diagnose different locations and for the most appropriate treatment planning. Endometriosis requires a multidisciplinary teamwork to manage these patients clinically and surgically.

Indirect and atypical imaging signals of endometriosis: A wide range of manifestations

Background

Whilst some imaging signs of endometriosis are common and widely accepted as ‘typical’, a range of ‘subtle’ signs could be present in imaging studies, presenting an opportunity to the radiologist and the surgeon to aid the diagnosis and facilitate preoperative surgical planning.

Objective

To summarise and analyse the current information related to indirect and atypical signs of endometriosis by ultrasound (US) and magnetic resonance imaging (MRI).

Methods

Through the use of PubMed and Google scholar, we conducted a comprehensive review of available articles related to the diagnosis of indirect signs in transvaginal US and MRI. All abstracts were assessed and the studies were finally selected by two authors.

Results

Transvaginal US is a real time dynamic exploration, that can reach a sensitivity of 79-94% and specificity of 94%. It allows evaluation of normal sliding between structures in different compartments, searching for adhesions or fibrosis.

MRI is an excellent tool that can reach a sensitivity of 94% and specificity of 77% and allows visualisation of the uterus, bowel loop deviation and peritoneal inclusion cysts. It also allows the categorisation and classification of ovarian cysts, rectovaginal and vesicovaginal septum obliteration, and small bowel endometriotic implants.

Conclusion

The use of an adequate mapping protocol with systematic evaluation and the reporting of direct and indirect signs of endometriosis is crucial for detailed and safe surgical planning.