Study Questions Value of Pelvic Ultrasound After Negative CT in Emergency Gynecologic Care

New research published in the Journal of the American College of Radiology (JACR) suggests that performing a pelvic ultrasound following a negative CT scan in emergency department (ED) settings provides limited clinical benefit, raising questions about routine use of the practice.

When women present to the ED with pelvic or abdominal pain, clinicians often face uncertainty in determining whether the cause is gynecologic. Current guidelines from the American College of Radiology recommend CT as the first-line imaging strategy. Nonetheless, many physicians also order pelvic ultrasound afterward to ensure urgent conditions such as ovarian torsion are not overlooked.

Researchers from Yale University and several collaborating hospitals sought to evaluate the usefulness of this additional imaging. Their study analyzed records from nine EDs in a large Northeastern health system that treats more than 500,000 patients annually. The sample included over 2,200 patients who underwent abdominopelvic CT scans between 2017 and 2022, followed by pelvic ultrasound.

Of these, 833 patients had CT results negative for gynecological pathology. Among them, nearly 54% (447 patients) had no new findings on ultrasound, while an additional 9% (74 patients) revealed only benign incidental findings such as simple ovarian cysts or small amounts of uterine fluid.

About 36% (302 patients) did show ultrasound results that warranted outpatient follow-up, though not immediate intervention. The most frequent findings were complex ovarian cysts (49%) and uterine fibroids (33%).

Crucially, only 10 patients—or 1.2% of the total cohort—had ultrasound findings requiring urgent action. These included eight suspected cases of pelvic inflammatory disease, though two were ultimately discharged without antibiotics once the diagnosis was ruled out, and two cases involving retained contraceptive products. Importantly, no cases of ovarian torsion or tubo-ovarian abscesses—the emergencies physicians most fear missing—were identified.

“Clinicians should carefully weigh the additional resource utilization against the potential benefit of early reassurance or diagnosis of benign findings,” wrote lead author Tamanna Hossin, MD, of Yale’s Department of Emergency Medicine, and colleagues.

The authors cautioned that while ultrasound may occasionally identify non-emergent issues, its marginal diagnostic yield raises concerns about unnecessary costs, extended ED stays, and potential harm from false positives or indeterminate results. “These cases highlight ultrasound’s marginal diagnostic utility and raise concerns about emotional or physical harm from false positives or indeterminate results in addition to added costs and increased ED length of stay,” they noted.

Still, the team acknowledged that ultrasound may provide value beyond detecting emergencies. For roughly one-third of patients with a negative CT, ultrasound revealed new but non-urgent findings, such as malpositioned intrauterine devices, which could guide outpatient management.

“From the perspective of the emergency clinician, the decision to order pelvic ultrasound may not be driven solely by concern for emergent pathology … but also by a desire to identify or exclude less urgent yet clinically relevant conditions,” the authors wrote. They emphasized that future research should investigate how often these incidental findings lead to meaningful changes in outpatient care.

In short, while pelvic ultrasound after a negative CT rarely changes immediate management in the ED, it may still hold selective value in uncovering issues relevant to long-term gynecologic care.