Intravenous and Oral Contrast vs Intravenous Contrast Alone Computed Tomography for the Visualization of Appendix and Diagnosis of Appendicitis in Adult Emergency Department Patients.
OBJECTIVE
The study sought to compare radiologist's ability to 1) visualize the appendix; 2) diagnose acute appendicitis; and 3) diagnose alternative pathologies responsible for acute abdominal pain among adult patients undergoing computed tomography (CT) scan with 3 different protocols: 1) intravenous (IV) contrast only; 2) IV and oral contrast with 1-hour transit time; and 3) IV and oral contrast with 3-hour transit time.


METHODS
We collected data of 225 patients; 75 consecutive patients with a clinical suspicion of appendicitis received oral contrast for 3 hours and IV contrast, 75 received oral contrast for 1 hour and IV contrast, and 75 trauma patients received IV contrast only. Three independent reviewers, blinded to final pathology, retrospectively analysed the cases and documented visualization of the appendix, periappendiceal structures, and their confidence in diagnosing appendicitis. Clinical diagnoses were derived from a combination of clinical, surgical, pathologic, or radiologic follow-up.


RESULTS
Frequency of visualizing the appendix within IV group alone was 87.3%, IV with oral for 1 hour was 94.1%, and IV with oral for 3 hours was 93.8%. Both oral contrast groups had 100% sensitivity and negative predictive value in diagnosis of acute appendicitis. Specificity for the 1- and 3-hour oral contrast groups was 94.1% and 96.1%, respectively and positive predictive value for both groups was 92%.


CONCLUSIONS
Our findings suggest that reader confidence in visualizing the appendix improved with addition of oral contrast as compared to IV contrast alone. One- and 3-hour oral regimens have a similar diagnostic performance in diagnosing appendicitis.
Department of Radiology, Foothills Medical Centre, Calgary, Alberta, Canada. Electronic address: aman.wadhwani@albertahealthservices.ca.
Aman
A
Wadhwani
Department of Radiology, Foothills Medical Centre, Calgary, Alberta, Canada.
Lancia
L
Guo
Department of Emergency Medicine, Foothills Medical Centre, Calgary, Alberta, Canada.
Erik
E
Saude
Department of Radiology, Foothills Medical Centre, Calgary, Alberta, Canada.
Hein
H
Els
Department of Emergency Medicine, Foothills Medical Centre, Calgary, Alberta, Canada.
Eddie
E
Lang
Department of Emergency Medicine, Foothills Medical Centre, Calgary, Alberta, Canada.
Andrew
A
McRae
Department of Radiology, Foothills Medical Centre, Calgary, Alberta, Canada.
Deepak
D
Bhayana
D015746:Abdominal Pain / Q000209:etiology; D061605:Administration, Intravenous; D000284:Administration, Oral; D000328:Adult; D001064:Appendicitis / Q000000981:diagnostic imaging*; D001065:Appendix / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D004636:Emergency Service, Hospital; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D016037:Single-Blind Method; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media
Appendicitis; Appendix; Computed tomography; Oral contrast