Geoffrey Merritt Rutledge MD, Presenter: Nothing to Disclose

Efren Jesus Flores MD, Abstract Co-Author: Nothing to Disclose

Sanjay Saini MD, Abstract Co-Author: Nothing to Disclose

Anjaneya Singh Kathait MBBS, Abstract Co-Author: Nothing to Disclose

Anand M. Prabhakar MD, Abstract Co-Author: Nothing to Disclose

To compare the outcomes of magnetic resonance imaging (MRI) with ultrasound (US) in the evaluation of patients with suspected acute appendicitis (AA) in the emergency room.

In this IRB approved, retrospective study, we reviewed all MRI reports performed in the emergency room for suspected AA, between May, 2010 and March, 2014. Demographic and clinical data were extracted via chart review. Pathology reports were used as the reference standard for disease confirmation. Completion times of MRI and US were calculated from the start and stop times on the images.

74 patients underwent MRI (71 female, 64 pregnant; mean age 29 years, range 17-51 years; mean gestational age 15.6 weeks, range 3-37 weeks). Ten patients had AA on surgical pathology. MRI correctly diagnosed AA in 10/10 cases (sensitivity 100%), was falsely positive in 2/64 cases (specificity 97%), and had no false negative diagnoses (positive predictive value of 83%, negative predictive value of 100%). The two patients who were misdiagnosed with AA on MRI underwent appendectomy and pathology demonstrated a hyperplastic polyp in one case and serosal congestion in the other case. US was performed concurrently in 56/74 patients, and correctly diagnosed AA in two cases and was falsely negative in six cases. MRI made six alternative diagnoses that were not described on US (two cases of colitis and one case each of cirrhosis with splenomegaly, polycystic ovarian syndrome, ruptured ovarian cyst, and hydronephrosis). No diagnoses made on US were missed on MRI. US was completed in significantly less time on average than was MRI (mean 17.6 min +/- 14.2 vs. 38.8 min +/- 14.6, p<0.01).

MRI demonstrates excellent sensitivity and specificity for AA and can also make alternative diagnoses. MRI took longer than US to complete, but future studies could focus on decreasing MRI scan times.

MRI is sensitive and specific for acute appendicitis and can make alternative diagnoses, and is recommended as an alternative to US for the evaluation of emergency room patients with suspected acute appendicitis.

Rutledge, G, Flores, E, Saini, S, Kathait, A, Prabhakar, A, MRI Offers Advantages Over Ultrasound for the Evaluation of Suspected Appendicitis in Emergency Room Patients.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015938.html