‘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.