MRI/CT Diagnostic Accuracy for Appendicitis Equivalent for Generalists and Specialists

Study shows general radiologists in community settings have nearly the same level of diagnostic accuracy as abdominal fellowship-trained providers.

Diagnostic accuracy with appendicitis is virtually equivalent between general radiologists and providers who completed abdominal fellowships.

In a new study published in Emergency Radiology, a team of investigators from the University of Wisconsin-Madison showed that general radiologists are just as proficient with these scans as are providers who complete an abdominal fellowship. This equivalency exists even though they encounter these MRI and CT scans less frequently in the community hospital setting.

These findings disproved the authors’ initial belief that general radiologists would have lower diagnostic accuracy.

“We found that community-based generalist radiologists demonstrated excellent accuracy when using MR to diagnose appendicitis,” said the team led by Michael D. Repplinger, M.D., Ph.D., clinical assistant professor in the department of emergency medicine. “Specifically, when comparing CT and MR images performed in tandem on patients seen in the ED for possible appendicitis, we found no statistically significant differences in accuracy among 198 paired image sets.”

For their study, the team assessed MRI and CT scan interpretations from six radiologists (three in community and academic settings each) over an 18-month period. Overall, the study included 198 patients, and the prevalence of appendicitis was 32.3 percent.

Based on their evaluation, the team determined that general radiologists had a sensitivity and specificity performance of 93.8 percent and 88.8 percent, respectively, for MR and 96.9 percent and 91.8 percent, respectively, for CT. In contrast, the fellowship-trained providers demonstrated sensitivity and specificity of 96.9 percent and 89.6 percent for MR, respectively, and 98.4 percent and 93.3 percent for CT, respectively.

Additionally, the team discovered that as the experience level grew for general radiologists, so did their accuracy. Specifically, they identified a significant increase in MR sensitivity (p=0.002) and a decrease in reading time – a reduction from 5 minutes to 3.9 minutes.

Despite being general radiologists, the team did note that these providers had significant familiarity with neuroradiology, as well as musculoskeletal radiology.

Ultimately, the team said, these findings could impact the imaging evaluation of suspected cases of appendicitis.

“This suggests MR may be a reliable, radiation-free imaging alternative to CT for the evaluation of appendicitis, including at community-based generalist radiology practices,” the team concluded.

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