Correspondence

Effect of CT on False Positive Diagnosis of Appendicitis and Perforation

N Engl J Med 2008; 358:972-973February 28, 2008

Article

To the Editor:

Acute appendicitis is one of the most common reasons for acute abdomen and the most common indication for emergency abdominal surgery in the United States.1 Surgeons have traditionally accepted up to a 20% rate of false positive diagnosis of acute appendicitis in order to minimize morbidity associated with a missed diagnosis. In clinical practice, the reported rate of false positive diagnosis of appendicitis among women has been as high as 42%.2 Several studies,3 including our own,4 have suggested that when used appropriately, preoperative computed tomography (CT) involving a variety of techniques improves outcomes in patients with clinically suspected appendicitis. However, several large-scale reviews of state databases have suggested no improvement in clinical outcomes in the era of presumably routine preoperative imaging for suspected acute appendicitis, and especially no decrease in the rates of false diagnosis of appendicitis or appendiceal perforation.5

Because of this discrepancy, we assessed the type of preoperative imaging and clinical outcomes in 1081 adults (616 men and 465 women), 16 to 90 years of age, who underwent surgery for suspected appendicitis between 1996 and 2006. During the 10-year study period, the core group of emergency physicians, surgeons, gastrointestinal pathologists, and abdominal radiologists was relatively stable, with the exception of the surgical group, which was expanded when a team of laparoscopic surgeons joined the practice during the last 3 years of the study period.

The annual rate of use of preoperative helical CT among patients who underwent surgery for suspected acute appendicitis increased from 20% in 1996 to 85% in 2006, reaching a peak of 93% in 2005 (P=0.001) (Table 1Table 1Preoperative Imaging and Outcomes among Adults Who Underwent Surgery for Suspected Appendicitis, 1996 to 2006.). The rate of use of ultrasonography steadily decreased from 24% in 1996 to 9% in 2006 (P<0.001). The rate of use of laparoscopic appendectomy increased from 0% in 1996 to 6% in 2002 and then to 23% in 2006.

From 1996 to 2006, the overall rate of false positive diagnosis of appendicitis among adults decreased significantly, from 24% to 3% (P=0.001). There was a significant inverse relationship between the annual increase in the rate of CT use and the annual decrease in the overall rate of false positive diagnosis of appendicitis among adults (P<0.001). The overall rate of pathologically proven appendiceal perforation decreased significantly, from 18% in 1996 to 5% in 2006 (P<0.001).

Our data suggest that the increased use of high-quality preoperative CT, with the results interpreted by experienced abdominal radiologists, has led to significantly improved clinical outcomes in adults, with a sustained decrease in rates of both false positive diagnosis of appendicitis and false positive diagnosis of appendiceal perforation.

Steven S. Raman, M.D.
Ferdnand C. Osuagwu, M.D.
Barbara Kadell, M.D.
Henry Cryer, M.D.
James Sayre, Ph.D.
David S.K. Lu, M.D.
David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1721

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Citing Articles (10)

Citing Articles

1. 1

   Richard G. Bachur, Kara Hennelly, Michael J. Callahan, Michael C. Monuteaux. (2011) Advanced Radiologic Imaging for Pediatric Appendicitis, 2005-2009: Trends and Outcomes. The Journal of Pediatrics
   CrossRef

2. 2

   Katherine Liu, Louis Fogg. (2011) Use of antibiotics alone for treatment of uncomplicated acute appendicitis: A systematic review and meta-analysis. Surgery 150:4, 673-683
   CrossRef

3. 3

   Daniel S. Tsze, Lisa M. Asnis, Roland C. Merchant, Siraj Amanullah, James G. Linakis. (2011) Increasing Computed Tomography Use for Patients With Appendicitis and Discrepancies in Pain Management Between Adults and Children: An Analysis of the NHAMCS. Annals of Emergency Medicine
   CrossRef

4. 4

   Boudewijn R. Toorenvliet, Fraukje Wiersma, Rutger F. R. Bakker, Jos W. S. Merkus, Paul J. Breslau, Jaap F. Hamming. (2010) Routine Ultrasound and Limited Computed Tomography for the Diagnosis of Acute Appendicitis. World Journal of Surgery 34:10, 2278-2285
   CrossRef

5. 5

   A. Randen, W. Laméris, H. W. Es, W. Hove, W. H. Bouma, M. S. Leeuwen, E. M. Keulen, V. P. M. Hulst, O. D. Henneman, P. M. Bossuyt, M. A. Boermeester, J. Stoker. (2010) Profiles of US and CT imaging features with a high probability of appendicitis. European Radiology 20:7, 1657-1666
   CrossRef

6. 6

   Pieter Poortman, Paul N.M. Lohle, Cees M. Schoemaker, Miguel A. Cuesta, Henk J.M. Oostvogel, Elly S.M. de Lange-de Klerk, Jaap F. Hamming. (2010) Improving the false-negative rate of CT in acute appendicitis—Reassessment of CT images by body imaging radiologists: A blinded prospective study. European Journal of Radiology 74:1, 67-70
   CrossRef

7. 7

   Krishna K. Varadhan, David J. Humes, Keith R. Neal, Dileep N. Lobo. (2010) Antibiotic Therapy Versus Appendectomy for Acute Appendicitis: A Meta-Analysis. World Journal of Surgery 34:2, 199-209
   CrossRef

8. 8

   Wytze Laméris, Adrienne van Randen, Peter M.N.Y.H. Go, Wim H. Bouma, Sandra C. Donkervoort, Patrick M.M. Bossuyt, Jaap Stoker, Marja A. Boermeester. (2009) Single and Combined Diagnostic Value of Clinical Features and Laboratory Tests in Acute Appendicitis. Academic Emergency Medicine 16:9, 835-842
   CrossRef

9. 9

   Pieter Poortman, Henk J.M. Oostvogel, Eelke Bosma, Paul N.M. Lohle, Miguel A. Cuesta, Elly S.M. de Lange-de Klerk, Jaap F. Hamming. (2009) Improving Diagnosis of Acute Appendicitis: Results of a Diagnostic Pathway with Standard Use of Ultrasonography Followed by Selective Use of CT. Journal of the American College of Surgeons 208:3, 434-441
   CrossRef

10. 10

    F Forghieri, M Luppi, F Narni, M Morselli, L Potenza, P Bresciani, F Volzone, G Rossi, A Rossi, L Trenti, P Barozzi, G Torelli. (2008) Acute appendicitis in adult neutropenic patients with hematologic malignancies. Bone Marrow Transplantation 42:10, 701-703
    CrossRef