Accuracy of MRI in Diagnosing Appendicitis during Pregnancy

Appendectomy for presumed appendicitis is the most common surgical emergency during pregnancy. Delayed diagnosis and treatment of appendicitis carries risk for the fetus and mother. We sought to evaluate the accuracy of MRI in pregnant patients with suspected appendicitis. All pregnant patients with suspected appendicitis between January 2014 and April 2016 were included. MRI reports were categorized into positive, negative, and inconclusive groups. Diagnosis of appendicitis was based on pathology report. Fifty-two patients were included in the study. The MRI was positive in two, negative in 29, and inconclusive in 21 patients. Twelve patients had surgery, 11 of which had positive appendicitis on pathology. Both positive MRI patients had appendicitis. In the negative MRI group, 3 of 29 (10%) had appendicitis. In the inconclusive MRI group, 6 of 21 (29%) had appendicitis. A positive MRI result was very specific with a 100 per cent positive predictive value; however, the sensitivity was as low as 18 per cent (diagnosed only 2 of 11 cases). Although a positive MRI finding was reliable in making a decision to operate, a negative or inconclusive MRI was not. In patients with a high clinical suspicion of appendicitis, surgery should still be considered even without definitive positive MRI findings.