Low-Dose vs. Standard-Dose CT for Appendicitis

Summary and Comment |
April 25, 2012

Low-Dose vs. Standard-Dose CT for Appendicitis

  1. J. Stephen Bohan, MD, MS, FACP, FACEP

Low-dose computed tomography was noninferior to standard-dose CT for evaluating suspected appendicitis in nonobese young adults.

  1. J. Stephen Bohan, MD, MS, FACP, FACEP

The rise in use of computed tomography (CT) for diagnosis of appendicitis has reduced the rate of negative appendectomy without increasing the rate of appendiceal perforation. Despite this advantage, there is concern about radiation exposure, particularly for young patients. Researchers in Korea randomized 891 patients ages 15 to 44 with suspected appendicitis to either low-dose (median dose, 116 mGy) or standard-dose (median dose, 521 mGy) CT with intravenous contrast. Entry criteria were referral for CT by emergency physicians and no contrast allergy, prior cross-sectional imaging for the current symptoms, or history of appendectomy. CT results were interpreted by expert abdominal radiologists or general radiologists, fellows, and residents, depending on time of day.

Overall, 1.5% of patients were obese. The negative appendectomy rate (the primary end point) was 3.5% in the low-dose group and 3.2% in the standard-dose group. The absolute difference of 0.3 percentage points and relative risk of 1.08 demonstrated noninferiority of the low-dose protocol. Rates of appendiceal perforation did not differ significantly between groups (27% and 23%).


Certainly, the less radiation exposure the better. The performance of the low-dose protocol in this study is encouraging. Unfortunately, the study population included few patients who were overweight or obese. On the basis of these results, low-dose computed tomography scan is a reasonable alternative to standard-dose CT scan for normal-weight patients with suspected appendicitis. However, patients with normal habitus also are good candidates for ultrasound evaluation, which involves no radiation exposure (JW Emerg Med Apr 10 2009).


Reader Comments (2)

Robert C. Barker

If the index of suspicion is high, why would one order a CT at all?

Competing interests: None declared

Bernard A. Yablin

Again,whatever happened to careful bimanual rectoabdominal palpation.

Competing interests: None declared

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