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Meta-Analysis
. 2019 Nov 19;2019(11):CD009977.
doi: 10.1002/14651858.CD009977.pub2.

Computed tomography for diagnosis of acute appendicitis in adults

Bo Rud  1 , Thomas S Vejborg  2 , Eli D Rappeport  2 , Johannes B Reitsma  3 , Peer Wille-Jørgensen  4
Affiliations
Meta-Analysis

Computed tomography for diagnosis of acute appendicitis in adults

Bo Rud et al. Cochrane Database Syst Rev. .

Abstract

Background: Diagnosing acute appendicitis (appendicitis) based on clinical evaluation, blood testing, and urinalysis can be difficult. Therefore, in persons with suspected appendicitis, abdominopelvic computed tomography (CT) is often used as an add-on test following the initial evaluation to reduce remaining diagnostic uncertainty. The aim of using CT is to assist the clinician in discriminating between persons who need surgery with appendicectomy and persons who do not.

Objectives: Primary objective Our primary objective was to evaluate the accuracy of CT for diagnosing appendicitis in adults with suspected appendicitis. Secondary objectives Our secondary objectives were to compare the accuracy of contrast-enhanced versus non-contrast-enhanced CT, to compare the accuracy of low-dose versus standard-dose CT, and to explore the influence of CT-scanner generation, radiologist experience, degree of clinical suspicion of appendicitis, and aspects of methodological quality on diagnostic accuracy.

Search methods: We searched MEDLINE, Embase, and Science Citation Index until 16 June 2017. We also searched references lists. We did not exclude studies on the basis of language or publication status.

Selection criteria: We included prospective studies that compared results of CT versus outcomes of a reference standard in adults (> 14 years of age) with suspected appendicitis. We excluded studies recruiting only pregnant women; studies in persons with abdominal pain at any location and with no particular suspicion of appendicitis; studies in which all participants had undergone ultrasonography (US) before CT and the decision to perform CT depended on the US outcome; studies using a case-control design; studies with fewer than 10 participants; and studies that did not report the numbers of true-positives, false-positives, false-negatives, and true-negatives. Two review authors independently screened and selected studies for inclusion.

Data collection and analysis: Two review authors independently collected the data from each study and evaluated methodological quality according to the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2) tool. We used the bivariate random-effects model to obtain summary estimates of sensitivity and specificity.

Main results: We identified 64 studies including 71 separate study populations with a total of 10,280 participants (4583 with and 5697 without acute appendicitis). Estimates of sensitivity ranged from 0.72 to 1.0 and estimates of specificity ranged from 0.5 to 1.0 across the 71 study populations. Summary sensitivity was 0.95 (95% confidence interval (CI) 0.93 to 0.96), and summary specificity was 0.94 (95% CI 0.92 to 0.95). At the median prevalence of appendicitis (0.43), the probability of having appendicitis following a positive CT result was 0.92 (95% CI 0.90 to 0.94), and the probability of having appendicitis following a negative CT result was 0.04 (95% CI 0.03 to 0.05). In subgroup analyses according to contrast enhancement, summary sensitivity was higher for CT with intravenous contrast (0.96, 95% CI 0.92 to 0.98), CT with rectal contrast (0.97, 95% CI 0.93 to 0.99), and CT with intravenous and oral contrast enhancement (0.96, 95% CI 0.93 to 0.98) than for unenhanced CT (0.91, 95% CI 0.87 to 0.93). Summary sensitivity of CT with oral contrast enhancement (0.89, 95% CI 0.81 to 0.94) and unenhanced CT was similar. Results show practically no differences in summary specificity, which varied from 0.93 (95% CI 0.90 to 0.95) to 0.95 (95% CI 0.90 to 0.98) between subgroups. Summary sensitivity for low-dose CT (0.94, 95% 0.90 to 0.97) was similar to summary sensitivity for standard-dose or unspecified-dose CT (0.95, 95% 0.93 to 0.96); summary specificity did not differ between low-dose and standard-dose or unspecified-dose CT. No studies had high methodological quality as evaluated by the QUADAS-2 tool. Major methodological problems were poor reference standards and partial verification primarily due to inadequate and incomplete follow-up in persons who did not have surgery.

Authors' conclusions: The sensitivity and specificity of CT for diagnosing appendicitis in adults are high. Unenhanced standard-dose CT appears to have lower sensitivity than standard-dose CT with intravenous, rectal, or oral and 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 two reasons. First, these 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.

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Conflict of interest statement

The review authors have no conflicts of interests

Figures

1
1
Study flow diagram. CT: computed tomography.
 US: ultrasonography.
2
2
Risk of bias and applicability concerns graph: review authors' judgements about each domain presented as percentages across included studies.
3
3
Risk of bias and applicability concerns summary: review authors' judgements about each domain for each included study.
4
4
Forest plot: CT regardless of contrast enhancement and radiation dose.
5
5
Summary ROC plot of CT for diagnosis of acute appendicitis (any contrast enhancement and radiation dose). The hollow symbols represent the pairs of sensitivity and specificity from the included studies; the symbols are scaled according to sample sizes of the studies. The solid circle represents the summary sensitivity and specificity. This summary point is surrounded by a 95% prediction region (interrupted line).
6
6
Summary ROC plot of CT with intravenous contrast enhancement versus unenhanced CT. See the caption for Figure 5 for a description of symbols and lines.
7
7
Summary ROC plot of CT with rectal contrast enhancement versus unenhanced CT. See the caption for Figure 5 for a description of symbols and lines.
8
8
Summary ROC plot of CT with oral contrast enhancement versus unenhanced CT. See the caption for Figure 5 for a description of symbols and lines.
9
9
Summary ROC plot of CT with intravenous and oral contrast enhancement versus unenhanced CT. See the caption for Figure 5 for a description of symbols and lines.
10
10
Summary ROC plot of low‐dose versus standard‐dose CT. See the caption for Figure 5 for a description of symbols and lines.
11
11
Exploration of heterogeneity: influence of CT‐scanner generation (CT with 16 detector rows or higher vs CT with fewer than 16 detector rows). See the caption for Figure 5 for a description of symbols and lines.
12
12
Exploration of heterogeneity: Influence of radiologists' experience. See the caption for Figure 5 for a description of symbols and lines.
13
13
Exploration of heterogeneity: influence of pre‐test suspicion of appendicitis. See the caption for Figure 5 for a description of symbols and lines.
14
14
Plain language summary flowchart.
1
1. Test
CT (unenhanced).
2
2. Test
CT (IV contrast).
3
3. Test
CT (oral contrast).
4
4. Test
CT (rectal contrast).
5
5. Test
CT (IV+oral contrast).
6
6. Test
CT (oral+rectal contrast).
7
7. Test
CT (IV+oral+rectal contrast).
8
8. Test
Low‐dose CT.
9
9. Test
CT (overall).
10
10. Test
Standard‐dose CT.
See this image and copyright information in PMC

Update of

References

References to studies included in this review

Antevil 2006 {published data only}
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Bouillot 2001 {published data only}
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Cakirer 2002 {published data only}
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Christopher 2002 {published data only}
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Holloway 2003 {published data only}
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Hong 2003 {published data only}
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Horton 2000 {published data only}
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Jacobs 2001 {published data only}
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Kan 2001 {published data only}
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Karabulut 2014 {published data only}
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Kepner 2012 {published data only}
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Keyzer 2004 {published data only}
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Keyzer 2009 {published data only}
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Kim 2008 {published data only}
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Kim 2012 {published data only}
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Lane 1999 {published data only}
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Lopez 2007 {published data only}
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Malone 1993 {published data only}
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Maluccio 2001 {published data only}
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Megibow 2002 {published data only}
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Mittal 2004 {published data only}
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Moteki 2009 {published data only}
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Nemsadze 2009 {published data only}
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Ozturk 2014 {published and unpublished data}
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Pakaneh 2008 {published data only}
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Park 2016 {published data only}
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Pickuth 2001 {published data only}
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Platon 2009 {published data only}
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Poortman 2003 {published data only}
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Rao 1997 {published data only}
    1. Rao PM, Rhea JT, Novelline RA, Mccabe CJ, Lawrason JN, Berger DL, et al. Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination. Radiology 1997;202(1):139‐44. - PubMed
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Rao 1998 {published data only}
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Rao 1999 {published data only}
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Repplinger 2015 {published and unpublished data}
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Sammalkorpi 2017 {published data only}
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Scott 2015 {published data only (unpublished sought but not used)}
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Sim 2013 {published and unpublished data}
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Stacher 1999 {published data only}
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Torbati 2003 {published data only}
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Walker 2000 {published data only}
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Wang 2012 {published and unpublished data}
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Weltman 2000 {published data only}
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Wijetunga 2001 {published data only}
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Wilson 2001 {published data only}
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Wise 2001 {published data only}
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Wong 2002 {published data only}
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Yuksekkaya 2004 {published data only}
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References to studies excluded from this review

Abo 2011 {published data only}
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Al‐Faouri 2016 {published data only}
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Ali 2017 {published data only}
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Anderson 2009 {published data only}
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Antevil 2004 {published data only}
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Bachar 2013 {published data only}
    1. Bachar I, Perry ZH, Dukhno L, Mizrahi S, Kirshtein B. Diagnostic value of laparoscopy, abdominal computed tomography, and ultrasonography in acute appendicitis. Journal of Laparoscopic & Advanced Surgical Techniques 2013; Vol. 23, issue 12:982‐9. - PubMed
Balthazar 1998 {published data only}
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Bendeck 2002 {published data only}
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Bixby 2006 {published data only}
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Brandt 2003 {published data only}
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Brontvein 2002 {published data only}
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Caglayan 2010 {published data only}
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Callahan 2015 {published data only}
    1. Callahan MJ, Anandalwar SP, MacDougall RD, Stamoulis C, Kleinman PL, Rangel SJ, et al. Pediatric CT dose reduction for suspected appendicitis: a practice quality improvement project using artificial gaussian noise ‐ part 2, clinical outcomes. AJR American Journal of Roentgenology 2015;204:636‐44. - PubMed
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Castro 2001 {published data only}
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Ceydeli 2006 {published data only}
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Chang 2013 {published data only}
    1. Chang CC, Wong YC, Wang LJ, Wu CH, Chen HW, Huang CC, et al. Computed tomography diagnostic values of acute appendicitis in different patient subgroups. Chinese Journal of Radiology (Taiwan) 2013;38:9‐14.
Chang 2016 {published data only}
    1. Chang CC, Wong YC, Wu CH, Chen HW, Wang LJ, Lee YH, et al. Diagnostic performance on low dose computed tomography for acute appendicitis among attending and resident radiologists. Iranian Journal of Radiology 2016;13:e33222. - PMC - PubMed
Chen 2010 {published data only}
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Chen 2016 {published data only}
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Chiu 2012 {published data only}
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Cuschieri 2008 {published data only}
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Dearing 2008 {published data only}
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Debnath 2015 {published data only}
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Dibble 2016 {published data only}
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Didier 2015 {published data only}
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Dillman 2016 {published data only}
    1. Dillman JR, Gadepalli S, Sroufe NS, Davenport MS, Smith EA, Chong ST, et al. Equivocal pediatric appendicitis: unenhanced MR imaging protocol for nonsedated children ‐ a clinical effectiveness study. Radiology 2016;279:216‐25. - PubMed
Elikashvili 2014 {published data only}
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Foley 2005 {published data only}
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Gaitini 2008 {published data only}
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Gaskill 2016 {published data only}
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Giuliano 2004 {published data only}
    1. Giuliano V, Giuliano C, Pinto F, Scaglione M. Rapid CT scan visualization of the appendix and early acute non‐perforated appendicitis using an improved oral contrast method. Emergency Radiology 2004;10(5):235‐7. - PubMed
Gwynn 2001 {published data only}
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Hoecker 2005 {published data only}
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Hookman 2000 {published data only}
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Horrow 2003 {published data only}
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Huynh 2007 {published data only}
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Iwahashi 2005 {published data only}
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Iwama 2002 {published data only}
    1. Iwama Y, Hamanaka A, Matsumoto S, Kawasaki R, Fushimi Y, Imagumbai T, et al. Detectability of the appendix with multidetector‐row CT scanning and multiplanar reconstruction [Japanese]. Japanese Journal of Clinical Radiology 2002;47(6):779‐84.
Jabra 1997 {published data only}
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Johansson 2007 {published data only}
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Kahn 2013 {published data only}
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Kailidou 2006 {published data only}
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Kaiser 2002 {published data only}
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Kaiser 2004 {published data only}
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Kamel 2000 {published data only}
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Karakas 2000 {published data only}
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Kharbanda 2007 {published data only}
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Kilincer 2017 {published data only}
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Kim 2008a {published data only}
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Kim 2011 {published data only}
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Kimura 2016 {published data only}
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Latifi 2011 {published data only}
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Lazarus 2007 {published data only}
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Lee 2001 {published data only}
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Lee 2006 {published data only}
    1. Lee KH, Kim YH, Hahn S, Lee KW, Lee HJ, Kim TJ, et al. Added value of coronal reformations for duty radiologists and for referring physicians or surgeons in the CT diagnosis of acute appendicitis. Korean Journal of Radiology 2006;7(2):87‐96. - PMC - PubMed
Lee 2016 {published data only}
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Leeuwenburgh 2013 {published data only}
    1. Leeuwenburgh MMN, Wiarda BM, Marinus JW, Vrouenraets BC, Gratama JWC, Spilt A, et al. Comparison of imaging strategies with conditional contrast enhanced CT and unenhanced MR imaging in patients suspected of having appendicitis: a multicenter diagnostic performance study. Radiology 2013;268(1):135‐43. - PubMed
Lin 2016 {published data only}
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Lowe 2000 {published data only}
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Lowe 2001 {published data only}
    1. Lowe LH, Draud KS, Hernanz‐Schulman M, Newton MR, Heller RM, Stein SM, et al. Nonenhanced limited CT in children suspected of having appendicitis: prospective comparison of attending and resident interpretations. Radiology 2001;221(3):755‐9. - PubMed
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McDonough 2002 {published data only}
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Morris 2002 {published data only}
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Moteki 2007 {published data only}
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Moteki 2011 {published data only}
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Mullins 2001 {published data only}
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Mullins 2001a {published data only}
    1. Mullins ME, Kircher MF, Ryan DP, Doody D, Mullins TC, Rhea JT, et al. Evaluation of suspected appendicitis in children using limited helical CT and colonic contrast material. AJR American Journal of Roentgenology 2001;176(1):37‐41. - PubMed
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Naoum 2002 {published data only}
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Paulson 2005 {published data only}
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Perez 2003 {published data only}
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Pickhardt 2011 {published data only}
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    1. Reeve T, Ferguson C. Imaging appendicitis: diagnostic accuracy of pre‐operative imaging and prevalence of negative appendicectomy in an Australian tertiary referral hospital. Journal of Medical Imaging and Radiation Oncology 2010;54(Suppl 1):A127.
Reich 2011 {published data only}
    1. Reich B, Zalut T, Weiner SG. An international evaluation of ultrasound vs. computed tomography in the diagnosis of appendicitis. International Journal of Emergency Medicine 2011;4(1):68‐74. - PMC - PubMed
Rhea 2005 {published data only}
    1. Rhea JT, Halpern EF, Ptak T, Lawrason JN, Sacknoff R, Novelline RA. The status of appendiceal CT in an urban medical center 5 years after its introduction: experience with 753 patients. AJR American Journal of Roentgenology 2005;184(6):1802‐8. - PubMed
Rosengren 2004 {published data only}
    1. Rosengren D, Brown AFT, Chu K. Radiological imaging to improve the emergency department diagnosis of acute appendicitis. EMA ‐ Emergency Medicine Australasia 2004;16(5‐6):410‐6. - PubMed
Sakai 2007 {published data only}
    1. Sakai T, Yagihashi N, Osawa T, Harada O, Ito H. Evaluation of the usefulness of computed tomography on diagnosis and management of acute abdomen [Japanese]. Japanese Journal of Gastroenterological Surgery 2007;40(1):15‐25.
Schuler 1998 {published data only}
    1. Schuler JG, Shortsleeve MJ, Goldenson RS, Perez‐Rossello JM, Perlmutter RA, Thorsen A. Is there a role for abdominal computed tomographic scans in appendicitis?. Archives of Surgery 1998;133(4):373‐7. - PubMed
Seo 2009 {published data only}
    1. Seo H, Lee KH, Kim HJ, Kim K, Kang SB, Kim SY, et al. Diagnosis of acute appendicitis with sliding slab ray‐sum interpretation of low‐dose unenhanced CT and standard‐dose i.v. contrast‐enhanced CT scans. AJR American Journal of Roentgenology 2009;193(1):96‐105. - PubMed
Siddiqui 2007 {published data only}
    1. Siddiqui AH, Afzal S. Perforated appendicitis: accuracy of CT diagnosis and correlation of CT findings with the length of hospital stay. Journal of the College of Physicians and Surgeons ‐ Pakistan 2007;17(12):721‐5. - PubMed
Sivit 2000 {published data only}
    1. Sivit CJ, Applegate KE, Stallion A, Dudgeon DL, Salvator A, Schluchter M, et al. Imaging evaluation of suspected appendicitis in a pediatric population: effectiveness of sonography versus CT. AJR American Journal of Roentgenology 2000;175(4):977‐80. - PubMed
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Sovtsov 2017 {published data only}
    1. Sovtsov SA, Revel‐Muroz ZA, Shkarednykh VY. [The use of computed tomography in the diagnosis of acute appendicitis]. Khirurgiia 2017;4:41‐5. - PubMed
Srinivasan 2010 {published data only}
    1. Srinivasan AS, Servaes S, Pena A, Pozo G, Lavelle J, Darge K. Utility of CT after sonography for suspected acute appendicitis. Pediatric Radiology 2010;40(4):582.
Stabile 2010 {published data only}
    1. Stabile Ianora AA, Moschetta M, Lorusso V, Scardapane A. Atypical appendicitis: diagnostic value of volume‐rendered reconstructions obtained with 16‐slice multidetector‐row CT. La Radiologia Medica 2010;115(1):93‐104. - PubMed
Stephen 2003 {published data only}
    1. Stephen AE, Segev DL, Ryan DP, Mullins ME, Kim SH, Schnitzer JJ, et al. The diagnosis of acute appendicitis in a pediatric population: to CT or not to CT. Journal of Pediatric Surgery 2003;38(3):367‐71. - PubMed
Stromberg 2007 {published data only}
    1. Stromberg C, Johansson G, Adolfsson A. Acute abdominal pain: diagnostic impact of immediate CT scanning. World Journal of Surgery 2007;31(12):2347‐54. - PubMed
Styrud 2000 {published data only}
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Suh 2011 {published data only}
    1. Suh SW, Choi YS, Park JM, Kim BG, Cha SJ, Park SJ, et al. Clinical factors for distinguishing perforated from nonperforated appendicitis: a comparison using multidetector computed tomography in 528 laparoscopic appendectomies. Surgical Laparoscopy, Endoscopy and Percutaneous Techniques 2011;21(2):72‐5. - PubMed
Suthikeeree 2010 {published data only}
    1. Suthikeeree W, Lertdomrongdej L, Charoensak A. Diagnostic performance of CT findings in differentiation of perforated from nonperforated appendicitis. Journal of the Medical Association of Thailand 2010;93(12):1422‐9. - PubMed
Tamburrini 2007 {published data only}
    1. Tamburrini S, Brunetti A, Brown M, Sirlin C, Casola G. Acute appendicitis: diagnostic value of nonenhanced CT with selective use of contrast in routine clinical settings. European Radiology 2007;17(8):2055‐61. - PubMed
Tan 2013 {published data only}
    1. Tan JW, Wan P, Kabir T, Ong HS. Use of the Alvarado score to stratify patients for CT evaluation in suspected appendicitis ‐ our proposed algorithm. Proceedings of Singapore Healthcare 2012;21:S140.
    1. Tan W, Pek WS, Kabir T, Goh YC, Chan WH, Wong WK, et al. The Alvarado score ‐ a clinical stratification for computed tomography evaluation in suspected appendicitis. Annals of the Academy of Medicine Singapore 2012;2:S20.
    1. Tan WJ, Pek W, Kabir T, Goh YC, Chan WH, Wong WK, et al. Alvarado score: a guide to computed tomography utilization in appendicitis. ANZ Journal of Surgery 2013;83:748‐52. - PubMed
Tatar 2016 {published data only}
    1. Tatar IG, Yilmaz KB, Sahin A, Aydin H, Akinci M, Hekimoglu B. Evaluation of clinical Alvarado scoring system and CT criteria in the diagnosis of acute appendicitis. Radiology Research and Practice 2016:Epub. - PMC - PubMed
Teo 2000 {published data only}
    1. Teo EL, Tan KP, Lam SL, Ong CL, Wong CS. Ultrasonography and computed tomography in a clinical algorithm for the evaluation of suspected acute appendicitis in children. Singapore Medical Journal 2000;41(8):387‐92. - PubMed
Toorenvliet 2010 {published data only}
    1. Toorenvliet BR, Wiersma F, Bakker RF, Merkus JW, Breslau PJ, Hamming JF. Routine ultrasound and limited computed tomography for the diagnosis of acute appendicitis. World Journal of Surgery 2010;34(10):2278‐85. - PMC - PubMed
Ujiki 2002 {published data only}
    1. Ujiki MB, Murayama KM, Cribbins AJ, Angelos P, Dawes L, Prystowsky JB, et al. CT scan in the management of acute appendicitis. Journal of Surgical Research 2002;105(2):119‐22. - PubMed
Unlu 2009 {published data only}
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Uyeda 2015 {published data only}
    1. Uyeda JW, Yu H, Ramalingam V, Devalapalli AP, Soto JA, Anderson SW. Evaluation of acute abdominal pain in the emergency setting using computed tomography without oral contrast in patients with body mass index greater than 25. Journal of Computer Assisted Tomography 2015;39:681‐6. - PubMed
Vajtai 2013 {published data only}
    1. Vajtai P, Hopkins K, Didier R. Accuracy in diagnosis of pediatric acute appendicitis: weight‐based CT protocols with traditional filtered back projection versus 60% CTDIvol‐reduced protocols with iterative reconstruction technique. Pediatric Radiology 2013;43:S555.
Van Randen 2011 {published data only}
    1. Randen A, Lameris W, Es HW, Hove W, Bouma WH, Leeuwen MS, et al. Profiles of US and CT imaging features with a high probability of appendicitis. European Radiology 2010;20(7):1657‐66. - PMC - PubMed
    1. Randen A, Lameris W, Es HW, Heesewijk HPM, Ramshorst B, Hove W, et al. A comparison of the accuracy of ultrasound and computed tomography in common diagnoses causing acute abdominal pain. European Radiology 2011;21(7):1535‐45. - PMC - PubMed
Wadhwani 2016 {published data only}
    1. Wadhwani A, Guo L, Saude E, Els H, Lang E, McRae A, et al. Intravenous and oral contrast vs intravenous contrast alone computed tomography for the visualization of appendix and diagnosis of appendicitis in adult emergency department patients. Canadian Association of Radiologists Journal 2016;67:234‐41. - PubMed
Wallace 2008 {published data only}
    1. Wallace CA, Petrov MS, Soybel DI, Ferzoco SJ, Ashley SW, Tavakkolizadeh A. Influence of imaging on the negative appendectomy rate in pregnancy. Journal of Gastrointestinal Surgery 2008;12(1):46‐50. - PubMed
Westerland 2016 {published data only}
    1. Westerland OA, Singh RK, Nagraj HC, Muthukumarasamy S, Ramesar K, Saunders MP, et al. Imaging in acute appendicitis: lessons learned from appendicectomy patients at two district general hospitals in the United Kingdom over a six‐year period. Hong Kong Journal of Radiology 2016;19:118‐25.
Weyant 2000 {published data only}
    1. Weyant MJ, Eachempati SR, Maluccio MA, Rivadeneira DE, Grobmyer SR, Hydo LJ, et al. Interpretation of computed tomography does not correlate with laboratory or pathologic findings in surgically confirmed acute appendicitis. Surgery 2000;128(2):145‐52. - PubMed
Weyant 2001 {published data only}
    1. Weyant MJ, Eachempati SR, Maluccio MA, Spigland N, Hydo LJ, Barie PS. The use of computed tomography for the diagnosis of acute appendicitis in children does not influence the overall rate of negative appendectomy or perforation. Surgical Infections 2001;2(1):19‐23. - PubMed
Yeoh 2016 {published data only}
    1. Yeoh T. Evaluation of computed tomography in diagnosis of acute appendicitis. Scottish Medical Journal 2016;61 (4):NP50.
Yi 2017 {published data only}
    1. Yi DY, Lee KH, Park SB, Kim JT, Lee NM, Kim H, et al. Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with USG and standard dose CT. Jornal de Pediatria 2017;23:23. - PubMed
Yoo 2009 {published data only}
    1. Yoo JK, Kim J‐E, Hyung SK, Hee YH. MDCT with coronal reconstruction: clinical benefit in evaluation of suspected acute appendicitis in pediatric patients. AJR American Journal of Roentgenology 2009;192(1):150‐2. - PubMed
Yun 2016 {published data only}
    1. Yun SJ, Kim HC, Yang DM, Kim SW, Rhee SJ, Shin JS, et al. Diagnostic usefulness of low‐dose nonenhanced computed tomography with coronal reformations in patients with suspected acute appendicitis: a comparison with standard‐dose computed tomography. Journal of Computer Assisted Tomography 2016;40:485‐92. - PubMed
Zourob 2016 {published data only}
    1. Zourob M, Board J, Baithun S, Cunningham FO, Saeed MF, Corbally MT, et al. A clinicopathological study of emergency appendectomy. Bahrain Medical Bulletin 2016;38:219‐22.

References to studies awaiting assessment

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Park 2018 {published data only}
    1. Park JH, Jeon J‐J, Lee SS, Dhanantwari AC, Sim JY, Kim Hae Y, et al. Can we perform CT of the appendix with less than 1 mSv? A de‐escalating dose‐simulation study. European Radiology 2018;28:1826‐34. - PubMed
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    1. Rao PM, Rhea JT, Novelline RA, Mccabe CJ, Lawrason JN, Sacknoff R. A new helical computed tomographic technique for appendiceal imaging: preliminary experience with the focused appendix computed tomographic examination. Emergency Radiology 1996;3(5):241‐6.
Singh 2018 {published data only}
    1. Singh NR, Luwang NT, Priyabarta Y, Singh CG, Singh WJ. Low‐dose noncontrast computed tomography in adults with acute appendicitis. Journal of the Medical Society 2018;32:111‐7.
Sippola 2018 {published data only}
    1. Sippola S, Virtanen J, Tammilehto V, Gronroos J, Hurme S, Niiniviita H, et al. The accuracy of low‐dose computed tomography protocol in patients with suspected acute appendicitis: the OPTICAP study. Annals of Surgery 2018;published online ahead of print. - PubMed
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