To establish the value of breathhold magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis. Over a 14-month period, 138 patients clinically suspected of having appendicitis were evaluated prospectively with MRI and comprised the study group. Fast turbo spin-echo breathhold T1, T2 and T2 fat suppression sequences were used in coronal and axial planes. The imaging results were recorded separately and subsequently correlated with clinical, radiological and histopathological follow-up. The effect of imaging strategies in patients suspected of appendicitis on hospital resources was calculated. Sixty-two of the 138 patients had a histopathologically proven appendicitis. MRI determined appendicitis in 63 patients, with one examination being false positive. The resulting sensitivity and specificity were 100% and 99%, respectively. MRI showed an alternative diagnosis in 41 of the 75 remaining patients. In 22 of the remaining 34 patients, a normal appendix was depicted with MRI. In two patients, where MRI showed no appendicitis, an alternative diagnosis or normal appendix, an unnecessary appendectomy was performed. The overall effect of using MRI in patients suspected of appendicitis on the use of hospital resources could have been a net saving between 55,746 euros and 72,534 euros. MRI has a high accuracy in detecting and excluding appendicitis, an alternative diagnosis or showing the normal appendix, and can be a valuable and cost-effective tool in the workup of patients clinically suspected of having appendicitis.

Our results suggest that MRI is helpful in the examination and diagnosis of acute appendicitis in pregnant patients. MRI may therefore be a good alternative to CT in pregnant patients for whom sonographic findings are nondiagnostic.

Our results suggest that MR imaging can be useful in the diagnosis of right colonic diverticulitis. An inflamed diverticulum with adjacent colonic wall thickening and surrounding inflamed fat are characteristic MR signs. MR imaging can be a valuable alternative to CT in young or pregnant patients who have suspected appendicitis and an equivocal US result.