Using ultrasound to diagnose pelvic pain can reveal unexpected pathologies, according to new research presented at the American Institute of Ultrasound in Medicine 2015 Annual Convention in Lake Buena Vista, Florida.

One of the most interesting findings was that transvaginal ultrasound is useful in diagnosing appendicitis, said Daniel Ohngemach, a fourth-year student at the Hofstra North Shore–LIJ School of Medicine in Hempstead, New York.

“You could see it beautifully. In the follow-up transabdominal scan, the images were not nearly as good and probably wouldn’t have been considered diagnostic for appendicitis,” he told Medscape Medical News.

“It’s a modality people wouldn’t usually run to for appendicitis, but you can see things that might otherwise be obstructed by bowel gas,” he explained.
His team searched the radiology department database at North Shore–LIJ to identify women who reported pelvic pain over a 3-year period. They found that ultrasounds performed in the emergency department or a hospital unit led to diagnoses doctors might not have predicted, including appendicitis, diverticulitis, colitis, tumors, small bowel obstruction, inflammatory bowel disease, pelvic inflammatory disease, fallopian tube torsion, endometriosis, and hernia.

Even when it is not diagnostic, an ultrasound, in combination with other tests, can lead to answers doctors don’t expect, Ohngemach said.

The thrust of the project was to make doctors aware that in addition to the many conditions ultrasound is considered diagnostic for, there are other conditions that the imaging technique can be used to diagnose, which could help expedite patient care, he explained.

Ultrasound First

When nonpregnant women report pelvic pain, ultrasound rather than CT or MRI should be the first imaging choice, write Beryl Benacerraf, MD, from Brigham and Women’s Hospital in Boston, and colleagues in a report published in the April issue of the American Journal of Obstetrics and Gynecology (2015;212:450-455).

Ultrasound doesn’t expose the patient to radiation and is at least as reliable as, and can be about four times less expensive than, CT, they report.

“Yet still today, many women with pelvic pain, masses, or flank pain first undergo CT scans and those with Müllerian duct anomalies typically have MRIs. Not uncommonly, CT or MRI of the pelvis often yield indeterminate and confusing findings that then require clarification by ultrasound imaging,” they explain.

A lot of the joy of it is to be able to see things that CT people think we won’t be able to see.
Ultrasound has come a long way since the “black dots on a white screen,” they point out. “Currently available 3D/4D volume ultrasound imaging can produce images of the female pelvis of comparable quality and orientation to those of MRI and CT, but without radiation and at relatively lower cost.”
It’s rare a radiologist who would choose CT first for pelvic pain, said Theodore Dubinsky, MD, from the University of Washington School of Medicine in Seattle.

“The only circumstance where they might do a CT first is for appendicitis, or maybe a kidney stone, but the vast majority of the time, ultrasound is first,” he told Medscape Medical News. For those two exceptions, CT might have a slightly higher sensitivity, but it is still valid to do the ultrasound first and then CT if the diagnosis is still unclear.

With ultrasound, “a lot of the joy of it is to be able to see things that CT people think we won’t be able to see,” said Dr Dubinsky.

CTs are often done first in emergency settings, acknowledged Maitray Patel, MD, from the Mayo Clinic in Scottsdale, Arizona. However, that might be less about best practices and more about available resources, he explained.

Most hospitals are set up so that CTs are easier to order than ultrasounds, he told Medscape Medical News. Some hospitals, including the Mayo in Arizona, don’t have 24/7 availability for ultrasounds. Someone can be called in to do one, but that adds to the wait time, especially in the middle of the night.

“CT scans are generally staffed 24/7,” Dr Patel said. Doctors in the emergency department “want to do what’s right for the patient, but they also want to do it as expeditiously as possible.”

He added that for women who are obese, it’s very difficult to do an ultrasound of the appendix. Ultrasound is also very operator-dependent; if the person available to do the ultrasound lacks the experience you’re looking for, a CT might be a better choice, he said.