A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Computer tomography (CT) is commonly used to evaluate suspected acute appendicitis; however, ionizing radiation limits its use in children. This study assesses 3T magnetic resonance imaging (MRI) as an imaging modality in the evaluation of suspected acute appendicitis in the pediatric population. This study is a retrospective review of prospectively‐collected data from 155 pediatric subjects who underwent MRI and 197 pediatric subjects who underwent CT for suspected acute appendicitis. Sensitivity, specificity, appendix visualization rate, positive appendicitis rate, and alternative diagnosis rate are determined. Sensitivity and specificity of MRI are 100% and 98%, 99% and 97% for CT (p = 0.61 and 0.53), respectively. Appendix visualization rate is 77% for MRI, 90% for CT (p = 0.0002), positive appendicitis rate is 25% for MRI, 34% for CT (p = 0.175), and alternative diagnosis rate is 3% for MRI, 3% for CT (p = 0.175). This study supports 3T MRI as a comparable modality to CT in the evaluation of suspected acute appendicitis in the pediatric population. Although MRI visualizes the appendix at a lower rate than CT, our protocol maintains 100% sensitivity with no false negatives. Our appendix visualization rate with 3T MRI (77%) is an improvement from published data from both 1.5T and 3T MRI systems. The exam time differential is clinically insignificant and use of MRI spares the patient the ionizing radiation and intravenous contrast of CT.