MRI as Accurate as Conditional CT in Detecting Adult Appendicitis

Conditional or immediate MR imaging was as accurate in detecting appendicitis in adult patients as was conditional CT, according to a study published in the journal Radiology.

Researchers from several centers in the Netherlands compared the diagnostic performance of MRI and CT in 230 adult patients (40 percent men, median age 35 years) who presented with symptoms of appendicitis. The patients underwent ultrasonography and subsequent contrast enhanced CT if the ultrasound was negative or inconclusive. The patients also underwent unenhanced MRI.

The MRI reader was blinded to the US and CT findings and an expert panel assigned diagnosis after three months.

A total of 115 CT and 223 MRIs were performed on the patients between March and September 2010. Appendicitis was the final diagnosis for 118 patients. The researchers found that the conditional MRI missed 3 percent of the appendicitis diagnoses and resulted in 8 percent false positives. Immediate MRI also missed 3 percent of diagnosis and produced 6 percent false positives. The MRI (conditional and immediate) sensitivity and specificity was comparable to the conditional CT, which missed 2 percent of the diagnoses and generated 10 percent false positives.

The researchers also found that conditional imaging resulted in more false positives in women than in men but immediate MRI did not.

The researchers concluded that the accuracy of both conditional and immediate MRIs was similar to that of conditional CT when investigating adults for appendicitis.