Acute appendicitis: Factors associated with inconclusive ultrasound study and the need for additional computed tomography.

Purpose: To identify variables associated with inconclusive ultrasound examination and the need for further abdominopelvic computed tomography (CT) examination for the diagnosis of acute appendicitis.

Materials And Methods: A total of 105 adult patients with acute appendicitis were included. There were 55 patients (38 men, 17 women; mean age, 23±9 [SD] years; range: 15-58 years) with a diagnosis of acute appendicitis using ultrasound alone and 50 patients (30 men, 20 women; mean age, 31±14 [SD] years; range: 16-83 years) who required further CT. Demographic, clinical, and biological criteria and appendix location were compared between the two groups to search for variables associated with the need of further CT.

Results: Patients who required further CT were older (31.1±14 [SD] years) and had a greater body mass index (BMI) (26.7±4.3 [SD]kg/m) than those who did not require CT (23±9 [SD] years and 22.9±3.4 [SD]kg/m), respectively (P<0.01). A greater proportion of patients with complicated acute appendicitis was observed in patients who required further CT (9/50; 18%) than in those who had only ultrasound (1/55; 2%) (P=0.012). Atypical appendix location was more frequent in patients who required CT (19/50; 36%) than in those who had only ultrasound (6/55; 11%) (P<0.001). There were no significant differences regarding gender, inflammatory syndrome and hours of imaging (on call vs. working hours) between the two groups.

Conclusion: Advanced age, high BMI, atypical appendix location, and complicated appendicitis are associated with inconclusive ultrasound and the need for further CT to diagnose acute appendicitis.