Ultrasound after negative CT scan offers little benefit in emergency gynecological care
Pelvic ultrasound after a negative CT scan offers little benefit in emergency gynecological care, according to new research published Thursday.
It often can be challenging for ED providers to determine whether pain in the pelvis and abdomen is stemming from the reproductive system. The American College of Radiology currently recommends CT as the first-line strategy to assess these scenarios. However, clinicians often also turn to ultrasound afterward amid concerns they may miss crucial concerns such as ovarian torsion, experts wrote in JACR.
Researchers recently aimed to assess the value of such additional imaging, examining data from nine EDs in a single Northeastern health system treating over 500,000 patients annually. They found that only about 1.2% of patients produced ultrasound findings necessitating immediate intervention, with no ovarian torsion nor tubo-ovarian abscesses—considered critical gynecological emergencies—detected.
“Clinicians should carefully weigh the additional resource utilization against the potential benefit of early reassurance or diagnosis of benign findings,” Tamanna Hossin, MD, with the Department of Emergency Medicine at Yale University, and co-authors wrote Aug. 21.
The study sample included a total of over 2,200 patients who underwent an abdominopelvic CT scan in an emergency room followed by a pelvic ultrasound sometime between 2017–2022. Of those, about 38% (or 833) had CT results classified as negative for gynecological pathologies, based on the study’s criteria. Among them, nearly 54% (or 447/833) had no new findings on subsequent ultrasound. An additional 9% (74) showed benign incidental findings such as simple cysts or a low amount of fluid in the lining of the uterus.
Meanwhile, ultrasound revealed clinical findings that warranted outpatient follow-up (but nothing urgent) for about 36% of these subjects (or 302). The most common among these cases were complex ovarian cysts (49% or 147/302) and uterine fibroids (33% or 99/302). Notably, only 10 patients or 1.2% had ultrasound findings requiring immediate intervention. These included eight cases of pelvic inflammatory disease—with two of them discharged without antibiotics after PID was ruled out—while the other 2/10 had suspected retained contraceptive products.
“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,” the authors advised.
However, Hossin and co-authors emphasized, despite the limited yield, pelvic ultrasound may still offer value. In one-third of patients with a negative CT, US revealed new findings warranting outpatient (but not emergency) follow-up. Diagnoses in these cases such as mispositioned intrauterine devices could help guide such future care, even if the concerns unearthed ended up being non-urgent.
“From the perspective of the emergency clinician, the decision to order pelvic ultrasound may not be driven solely by concern for emergent pathology (e.g., torsion or [tubo-ovarian abscesses]), but also by a desire to identify or exclude less urgent yet clinically relevant conditions,” the authors advised. “As such, imaging decisions in this setting must balance benefits against costs including clinical uncertainty, patient expectations, risk of incidental findings, and resource constraints (ED length of stay, availability of imaging etc.). Future work might explore how often these non-emergent findings lead to meaningful changes in outpatient care.”
Read more in the Journal of the American College of Radiology, including potential study limitations.
Marty Stempniak has covered healthcare since 2012, with his byline appearing in the American Hospital Association's member magazine, Modern Healthcare and McKnight's. Prior to that, he wrote about village government and local business for his hometown newspaper in Oak Park, Illinois. He won a Peter Lisagor and Gold EXCEL awards in 2017 for his coverage of the opioid epidemic.