Imaging may save women from needless appendectomy

June 16, 2006

All women of reproductive age with suspected appendicitis should be routinely imaged with ultrasound, CT, or both methods if clinically necessary prior to surgery, a radiologist said at the Stanford MDCT conference on Thursday.

All women of reproductive age with suspected appendicitis should be routinely imaged with ultrasound, CT, or both methods if clinically necessary prior to surgery, a radiologist said at the Stanford MDCT conference on Thursday.

In other patient groups, imaging with ultrasound or CT should be used selectively to help assess complex cases of suspected appendicitis, according to Dr. R. Brooke Jeffrey of Stanford University.

Female patients' gynecologic conditions can often mimic appendicitis. Therefore, clinical assessment is much trickier, and the risk of performing unnecessary surgery is higher in this population. Imaging can help provide accurate assessment, discharge patients earlier, and avoid subjecting women to the risks of needless surgery, Jeffrey said.

There are also financial benefits, as appendectomy costs about $25,000.

"The single most important benefit of imaging is reducing unnecessary surgery. Eliminating negative appendectomy should be one of our primary goals," Jeffrey said.

A large three-year retrospective study published by Stanford in 2002 found that imaging with CT and ultrasound helped dramatically reduce the number of unnecessary appendectomies in women over 16 years of age. In this patient group, the negative appendectomy rate was 28% for those who went straight to surgery. It was only 5% for those who underwent CT first and 4% for those who had ultrasound.

Which study to use, CT or ultrasound, is a matter of institutional preference. There has been a shift away from ultrasound to CT in suspected appendicitis, and now only 20% of cases are imaged with ultrasound. Ultrasound's overall accuracy is lower than CT's, with a sensitivity of about 85% versus mid-90s for CT. And the normal appendix can be difficult to visualize with ultrasound.

"We are now in the era of CT, with high-resolution volumetric scanning," Jeffrey said.

Despite this shift in practice, however, it's important to remember the value of radiation-free ultrasound, particularly in women's imaging, he said.

"Ultrasound has tremendous advantages. It's safe for use in pregnant patients. It's an interactive real-time technique," Jeffrey said.

Ultrasound is also better than CT for imaging patients with little or no body fat.

"We need to maintain our ultrasound skills. It should be the first study in patients who are thin, young, or pregnant," Jeffrey said.

When performing ultrasound imaging of patients with abdominal pain, it's important to ask patients to point out exactly where the pain is and scan that area.

Sometimes, more than one imaging study is needed.

"Ultrasound and CT are complementary, and we should never be afraid to use both if necessary to make a diagnosis to avoid a $25,000 negative appendectomy. I have no compunction about using both," Jeffrey said.