Interobserver agreement with the new BI-RADS terminology is good and validates the US lexicon. Subcategories 4a, 4b, and 4c are useful in predicting the likelihood of malignancy.

Low dose (<3 mSv) noncontrast CT (NCCT) is the imaging study of choice for accurate evaluation of patients with acute onset of flank pain and suspicion of stone disease (sensitivity 97%, specificity 95%). NCCT can reliably characterize the location and size of an offending ureteral calculus, identify complications, and diagnose alternative etiologies of abdominal pain such as appendicitis. By comparison, the sensitivity of radiographs (59%) and ultrasound (24-57%) for the detection of renal and ureteral calculi is relatively poor. Ultrasound can accurately diagnose pelvicaliectasis and ureterectasis, but it may take several hours for these findings to develop. In the pregnant patient, however, ultrasound is a first line test as it does not expose the fetus to ionizing radiation. MR is an accurate test for the diagnosis of pelvicaliectasis and ureterectasis, but is less sensitive than CT for the diagnosis of renal and ureteral calculi. For patients with known stone disease whose stones are visible on radiographs, radiographs are a good tool for post-treatment follow-up.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Imaging plays a key role in the diagnostic evaluation of women for infertility. The pelvic causes of female infertility are varied and range from tubal and peritubal abnormalities to uterine, cervical, and ovarian disorders. In most cases, the imaging work-up begins with hysterosalpingography to evaluate fallopian tube patency. Uterine filling defects and contour abnormalities may be discovered at hysterosalpingography but typically require further characterization with hysterographic or pelvic ultrasonography (US) or pelvic magnetic resonance (MR) imaging. Hysterographic US helps differentiate among uterine synechiae, endometrial polyps, and submucosal leiomyomas. Pelvic US and MR imaging help further differentiate among uterine leiomyomas, adenomyosis, and the various müllerian duct anomalies, with MR imaging being the most sensitive modality for detecting endometriosis. The presence of cervical disease may be inferred initially on the basis of difficulty or failure of cervical cannulation at hysterosalpingography. Ovarian abnormalities are usually detected at US. The appropriate selection of imaging modalities and accurate characterization of the various pelvic causes of infertility are essential because the imaging findings help direct subsequent patient care.

Clinical diagnosis of the cause of abdominal pain in a pregnant patient is particularly difficult because of multiple confounding factors related to normal pregnancy. Magnetic resonance (MR) imaging is useful in evaluation of abdominal pain during pregnancy, as it offers the benefit of cross-sectional imaging without ionizing radiation or evidence of harmful effects to the fetus. MR imaging is often performed specifically for diagnosis of possible appendicitis, which is the most common illness necessitating emergency surgery in pregnant patients. However, it is important to look for pathologic processes outside the appendix that may be an alternative source of abdominal pain. Numerous entities other than appendicitis can cause abdominal pain during pregnancy, including processes of gastrointestinal, hepatobiliary, genitourinary, vascular, and gynecologic origin. MR imaging is useful in diagnosing the cause of abdominal pain in a pregnant patient because of its ability to safely demonstrate a wide range of pathologic conditions in the abdomen and pelvis beyond appendicitis.

Accurate diagnosis of adnexal torsion is often challenging, as clinical presentation is nonspecific and the differential for pelvic pain is broad. However, prompt diagnosis and treatment is critical to good clinical outcomes and preservation of the ovary and/or fallopian tube. Ultrasound (US) imaging is most frequently used to assess torsion. However, as computed tomography (CT) utilization in the emergency setting has increased, there are times when CT is the initial imaging test. Additionally, the nonspecific clinical presentation may initially be interpreted as gastrointestinal in etiology, where CT is the preferred exam. For these reasons, it is imperative to know the findings of adnexal torsion on CT as well as US. Magnetic resonance imaging (MRI) is helpful in cases where the diagnosis remains unclear and is particularly helpful in the young or pregnant patient with equivocal sonographic findings, as it provides excellent soft tissue contrast without ionizing radiation. This article will illustrate the findings of surgically confirmed ovarian and fallopian tube torsion on US, CT, and MRI, including those in the pregnant patient. Ovarian enlargement, adnexal mass, twisting of the vascular pedicle, edematous and heterogeneous appearance of the ovary, peripheral ovarian follicles, free fluid, uterine deviation towards the side of torsion, adnexal fat stranding, tubal dilatation, and decreased adnexal enhancement will be reviewed. Familiarity with the range of imaging findings across multiple modalities is key to improving the likelihood of timely diagnosis and therefore improved clinical outcomes.

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ObjectiveAbdominal pain during pregnancy can be caused by a wide variety of diseases including disorders of the obstetric, gynecologic, gastrointestinal, hepatobiliary, genitourinary, and vascular systems. Some causes are unique to pregnancy, are exacerbated by pregnancy, or require an altered imaging algorithm for diagnosis during pregnancy. The educational objectives of this review article are for the participant to exercise, self-assess, and improve his or her understanding of the imaging evaluation of abdominal pain during pregnancy. ConclusionThis article reviews the causes of abdominal pain that are unique to pregnancy as well as some of the more common and severe causes of abdominal pain in which the imaging workup differs in the pregnant population. The relative advantages of using ultrasound, CT, and MRI to help establish the cause of the pain are also reviewed.

CT findings established the diagnosis in 35% of examinations in pregnant women with abdominal pain (28 of 80), with a negative predictive value of 99% for appendicitis; when CT followed negative US findings, CT findings established the diagnosis in 30% of patients.