Question

In adult patients presenting to the ED with acute abdominal pain and suspected of having acute appendicitis, what are the test characteristics of non-contrast helical CT?

Reviewed by

Veronica Hlibczuk, MD; Judith Dattaro, MD; Zhezhen Jin, PhD; Louise Falzon, BA, Michael Brown, MD

Date

March, 2009

Expiration date

March, 2011

Clinical bottom line

Non-contrast CT has excellent sensitivity and specificity for the diagnosis of acute appendicitis in adults.

Search strategy

MEDLINE, EMBASE, the Cochrane Library, ACP Journal Club, Emergency Medicine Abstracts, and the bibliographies of previous systematic reviews.

Citations

1. Ashraf, K., Ashraf O, Bari V, et al. Role of focused appendiceal computed tomography in clinically equivocal acute appendicitis. Journal of the Pakistan Medical Association 2006;56(5):200-203.

2. Ege, G, Akman H, Sahin A, et al. Diagnostic value of unenhanced helical CT in adult patients with suspected acute appendicitis. British Journal of Radiology 2002;75(897):721-725.

3. Horton, MD,Counter SF, Florence MG, et al. A prospective trial of computed tomography and ultrasonography for diagnosing appendicitis in the atypical patient. American Journal of Surgery 2000; 179(5):379-381

4. in't Hof KH, van Lankeren W, Krestin GP, et al. Surgical validation of unenhanced helical computed tomography in acute appendicitis. British Journal of Surgery 2004;91(12):1641-1645.

5. Keyzer C, Zalcman M, De Maertelaer V, et al. Comparison of US and unenhanced multi-detector row CT in patients suspected of having acute appendicitis. Radiology 2005;236(2):527-534.

6. Stacher R, Portugaller H, Preidler KW, et al. Acute appendicitis in unenhanced spiral CT: Diagnostic luxury or benefit. RoFo Fortschritte auf dem Gebiet der Rontgenstrahlen und der Bildgebenden Verfahren 1999;171(1):26-31.

7. Tamburrini S, Brunetti A, Brown M, et al. Acute appendicitis: Diagnostic value of nonenhanced CT with selective use of contrast in routine clinical settings. European Radiology 2007;17(8):2055-2061

Primary study characteristics

Study Population
Adult patients presenting or referred to the ED with acute abdominal pain suspicious for acute appendicitis, but not immediate candidates for surgery.

Interventions
Non-contrast helical computed tomography.

Outcome measures
Acute appendicitis diagnosed at surgery or pathology; acute appendicitis not present if normal appendix at surgery or negative clinical follow-up for minimum of 2 weeks. Critical appraisal All included an adequate patient spectrum and reference standard; however, all except one study were prone to differential verification bias and only 2 studies clearly reported indeterminate CT results.

Results

Pooled Test Characteristics

Point Estimate (95%CI)

Sensitivity

92.7% (89.5; 95.0%)

Specificity

96.1% (94.2; 97.5%)

LR +

24

LR -

0.08