Summary of findings'. 'Summary of findings table.
| Population | Adults (> 14 years of age) with suspected acute appendicitis based on history, physical examination, and/or blood tests | |||||
| Settings | Emergency and Radiology Departments in secondary and tertiary care settings | |||||
| Index test | Computed tomography of the abdomen | |||||
| Reference standard | Histological examination of the resected appendix or intraoperative findings in persons who had surgery. Clinical follow‐up for persons who did not have surgery | |||||
| Target condition | Acute appendicitis | |||||
| Number of studies | 64 studies including 71 separate study populations with a total of 10,280 participants ‐ 4583 with and 5697 without acute appendicitis | |||||
| Methodological concerns | The methodological quality was generally poor, particularly with respect to the reference test and the flow and timing domains. For these domains, few studies were at low risk of bias. Differential verification was used in most studies because some of the participants with suspected acute appendicitis did not have surgery. Clinical follow‐up for these participants was inadequate, incomplete, or poorly described in most studies | |||||
| Results | Number of studies (study populations)a |
Summary sensitivity (95% CI) | Summary specificity (95% CI) | Prevalence of appendicitis
(25% percentile 50% percentile 75% percentile)b |
Post‐test probability following a positive CT outcome (95% CI) |
Post‐test probability following a negative CT outcome (95% CI) |
| CT overall | 64 (71) | 0.95 (0.93‐0.96) | 0.94 (0.92‐0.95) |
0.32 0.43 0.58 |
0.88 (0.85‐0.90) 0.92 (0.90‐0.94) 0.96 (0.94‐0.96) |
0.02 (0.02‐0.03) 0.04 (0.03‐0.05) 0.07 (0.05‐0.09) |
| Unenhanced CT | 19 (19) |
0.91 (0.87‐0.93) | 0.94 (0.90‐0.96) | 0.32 0.43 0.58 |
0.87 (0.82‐0.92) 0.92 (0.88‐0.95) 0.95 (0.93‐0.97) |
0.04 (0.03‐0.06) 0.07 (0.05‐0.09) 0.12 (0.09‐0.16) |
| CT with intravenous contrast enhancement | 17 (18) |
0.96 (0.92‐0.98) |
0.93 (0.90‐0.95) | 0.32 0.43 0.58 |
0.87 (0.82‐0.90) 0.91 (0.88‐0.94) 0.95 (0.93‐0.96) |
0.02 (0.01‐0.04) 0.03 (0.02‐0.06) 0.06 (0.03‐0.11) |
| CT with rectal contrast enhancement | 9 (9) |
0.97 (0.93‐0.99) | 0.95 (0.90‐0.98) | 0.32 0.43 0.58 |
0.91 (0.81‐0.96) 0.94 (0.87‐0.97) 0.97 (0.93‐0.99) |
0.02 (0.01‐0.04) 0.03 (0.01‐0.06) 0.05 (0.02‐0.10) |
| CT with oral contrast enhancement | 7 (7) |
0.89 (0.81‐0.94) |
0.94 (0.90‐0.97) |
0.32 0.43 0.58 |
0.88 (0.81‐0.93) 0.92 (0.87‐0.96) 0.96 (0.92‐0.98) |
0.05 (0.03‐0.09) 0.08 (0.04‐0.14) 0.14 (0.08‐0.22) |
| CT with oral and intravenous contrast enhancement | 15 (15) |
0.96 (0.93‐0.98) | 0.94 (0.92‐0.96) | 0.32 0.43 0.58 |
0.89 (0.85‐0.92) 0.93 (0.90‐0.95) 0.96 (0.94‐0.97) |
0.02 (0.01‐0.03) 0.03 (0.02‐0.05) 0.05 (0.03‐0.09) |
| Low‐dose CT | 7 (8) |
0.94 (0.90‐0.97) |
0.94 (0.91‐0.96) |
0.32 0.43 0.58 |
0.88 (0.82‐0.92) 0.92 (0.88‐0.95) 0.96 (0.93‐0.97) |
0.03 (0.02‐0.05) 0.04 (0.02‐0.08) 0.08 (0.04‐0.13) |
| Conclusion | Sensitivity and specificity of CT for diagnosing acute appendicitis in adults are high. Unenhanced standard‐dose CT appears to have lower sensitivity than standard‐dose CT with intravenous, rectal, or oral+intravenous contrast enhancement. Use of different types of contrast enhancement or no enhancement does not appear to affect specificity. Differences in sensitivity and specificity between low‐dose and standard‐dose CT appear to be negligible. The results of this review should be interpreted with caution for 2 reasons. First, the results are based on studies of low methodological quality. Second, the comparisons between types of contrast enhancement and radiation dose may be unreliable because they are based on indirect comparisons that may be confounded by other factors | |||||
CI: confidence interval. CT: computed tomography. aIn five studies, participants were randomly allocated to two CT‐protocols, and in another study to three CT‐protocols. These protocols differed with respect to contrast enhancement and radiation dose. This generated seven additional study populations, which were included as separate studies in the meta‐analyses.
bThe distribution of the prevalence of appendicitis was roughly similar in the included studies across subgroups. Therefore, to facilitate comparison of post‐test probabilities between subgroups, these probabilities were calculated for the 25%, 50%, and 75% percentiles of prevalence for all 71 study populations.