MR imaging a ‘suitable alternative’ to CT when evaluating patients for acute appendicitis
Physicians regularly turn to CT to evaluate patients who arrive at a hospital emergency department (ED) due to acute appendicitis. According to a new study published in Radiology, the diagnostic accuracy of MR imaging compares favorably to that of CT when diagnosing acute appendicitis, meaning patients can receive the same level of care without the ionizing radiation exposure.
CT and MR imaging were performed in tandem on more than 190 nonpregnant patients being evaluated for appendicitis. The patients’ mean age was more than 31 years old. Three abdominal radiologists retrospectively interpreted the images, blinded to the clinical outcomes.
Overall, when a score of 3 or higher was considered a positive test result, the sensitivity was 96.9 percent and the specificity was 81.3 percent for MR imaging. For CT, the sensitivity was 98.4 percent and the specificity was 89.6 percent.
When a cutoff level of 4 of higher was used, however, there was “no statistical difference” between the two methods. The sensitivity was 96.9 percent and the specificity was 89.6 percent for MR imaging. For CT, the sensitivity was 98.4 percent and the specificity was 93.3 percent.
“We observed no statistically significant differences in the test characteristics of MR imaging versus CT at the 4 or higher cutoff level,” wrote lead author Michael D. Repplinger, MD, PhD, departments of emergency medicine and radiology at the University of Wisconsin-Madison, and colleagues. “We conclude that MR imaging may be a suitable alternative for the evaluation of acute appendicitis when MR imaging availability and expertise exist, particularly in patients who are not expected to require sedation.”
Repplinger et al. noted that their study did have limitations. They enrolled a “relatively small number of patients,” for instance, and all imaging and reads were performed at a single academic medical center.
In addition, CT was performed before MR imaging for each patient. Could this have impacted the study results? “For most, that mandated that oral contrast material be ingested,” the authors wrote. “The effect of this oral contrast material on the diagnostic accuracy observed for the MR imaging protocol was not evaluated in our study; this is another important factor to investigate in the future.”
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.