Noncontrast CT Accurately Diagnoses Acute Appendicitis in Adults


Last Updated: 2010-01-22 18:41:49 -0400 (Reuters Health)

By Victoria Stern

NEW YORK (Reuters Health) - Noncontrast computed tomography is sensitive and specific for acute appendicitis in adults and is a reasonable alterative to CT with contrast, according to a systematic review published in the January Annals of Emergency Medicine.

"Noncontrast CT is advantageous because patients can be diagnosed more quickly, and there's no risk that a patient will have a bad reaction to the contrast material," first author Dr. Veronica Hlibczuk told Reuters Health.

Dr. Hlibczuk, from Columbia University Medical Center in New York City, and her colleagues identified 7 studies involving 1060 patients that compared findings on noncontrast CT to findings at surgery in adults with suspected acute appendicitis.

When they pooled the data from these reports, the authors found that the odds of a false positive diagnosis with noncontrast CT are extremely slim (positive likelihood ratio, 24), and a false negative diagnosis is also unlikely (negative likelihood ratio, 0.08). The pooled estimates for sensitivity and specificity of noncontrast CT were both high: 92.7% and 96.1%, respectively.

Dr. Hlibczuk pointed out that a limitation to using noncontrast CT is that not all radiologists have the training and experience to interpret the scans.

Nevertheless, she said, "we feel comfortable saying that noncontrast CT can be used instead of contrast to diagnose acute appendicitis in adults."

The same issue of the journal contains a Clinical Policy statement from the American College of Emergency Physicians on evaluation and management of patients with suspected acute appendicitis.

The authors of the statement, led by Dr. John M. Howell of Fairfax Hospital in Virginia, point out: "Not every patient with possible appendicitis needs abdominal imaging....For example, patients with a very low clinical suspicion for appendicitis may be discharged with minimal or no testing. Similarly, patients with high clinical suspicion for appendicitis may be referred to a surgeon, with minimal or no testing. If the clinical presentation warrants, a surgical consultant should be notified as early as is clinically warranted."

Ann Emerg Med 2010.

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