Computed tomography is probably a better diagnostic test than ultrasonography for adults and adolescents with suspected acute appendicitis

Question

Is computed tomography diagnostically superior to ultrasonography for acute appendicitis in adults and adolescents?

Study design

Systematic review with meta-analysis.

Main results

Twenty-two studies (nineteen prospective cohort studies and three randomised controlled trials) were included in the review. Eight were of computed tomography, ten were of ultrasonography and four were of both. Recruitment to the majority of studies (21/22) was based on symptoms at presentation, physical examination and basic laboratory tests. Meta-analysis showed that both tests had high diagnostic accuracy (sensitivity: 0.90, 95% CI 0.86 to 0.92 for computer tomography v 0.84, 95% CI 0.80 to 0.86 for ultrasonography; specificity: 0.92, 95% CI 0.89 to 0.93 for computer tomography v 0.79, 95% CI 0.76 to 0.82 for ultrasonography). Meta-analysis of four studies that directly compared the tests with one another found that computed tomography increased the certainty of diagnosis more than ultrasonography (positive likelihood ratio: 12.2, 95% CI 7.1 to 21.2 with computed tomography v 3.4, 95% CI 2.4 to 4.8 with ultrasonography; negative likelihood ratio: 0.05, 95% CI 0.02 to 0.12 with computed tomography v 0.33, 95% CI 0.19 to 0.55 with ultrasonography). Sub-group analyses in studies of adults (≥18 years); those with differing presentations (suspected v atypical); and those including a high number of women (> 67%) found similar results.

Authors’ conclusions

Computed tomography is superior to appendiceal ultrasonography for diagnosing acute appendicitis in adults and adolescents with suspected appendicitis.