Intravenous contrast alone vs intravenous and oral contrast computed tomography for the diagnosis of appendicitis in adult ED patients

Abstract

Objective: When the diagnosis of appendicitis is uncertain, computerized tomography (CT) scans are frequently ordered. Oral contrast is often used but is time consuming and of questionable benefit. This study compared CT with intravenous contrast alone (IV) to CT with IV and oral contrast (IVO) in adult patients with suspected appendicitis.

Methods: This is a prospective, randomized study conducted in a community teaching emergency department (ED). Patients with suspected appendicitis were randomized to IV or IVO CT. Scans were read independently by 2 designated study radiologists blinded to the clinical outcome. Surgical pathology was used to confirm appendicitis in patients who went to the operating room (OR). Discharged patients were followed up via telephone. The primary outcome measure was the diagnosis of appendicitis. Secondary measures included time from triage to ED disposition and triage to OR.

Results: Both IV (n = 114) and IVO (n = 113) scans had 100% sensitivity (95% confidence interval [CI], 89.3-100 and 87.4-100, respectively) and negative predictive value (95% CI, 93.7-100 and 93.9-100, respectively) for appendicitis. Specificity of IV and IVO scans was 98.6 and 94.9 (95% CI, 91.6-99.9 and 86.9-98.4, respectively), respectively, with positive predictive values of 97.6 and 89.5 (95% CI, 85.9-99.9 and 74.2-96.6). Median times to ED disposition and OR were 1 hour and 31 minutes (P < .0001) and 1 hour and 10 minutes (P = .089) faster for the IV group, respectively. Patients with negative IV scans were discharged nearly 2 hours faster (P = .001).

Conclusions: Computerized tomography scans with intravenous contrast alone have comparable diagnostic performance to IVO scans for appendicitis in adults. Patients receiving IV scans are discharged from the ED faster than those receiving IVO scans.

Trial registration: ClinicalTrials.gov NCT00734825.