(Radiology Review) Does preoperative CT increase diagnostic accuracy in children suspected of having acute appendicitis? Pediatric surgeons from Massachusetts General Hospital, Boston, recently raised this question in the Journal of Pediatric Surgery.
According to the group, acute appendicitis is difficult to diagnose because many alternate problems present with abdominal pain as the main symptom and can imitate appendicitis. Focused appendiceal CT and ultrasound are commonly performed, and demonstrate similar sensitivity and specificity, but CT boasts a less variable accuracy. They compared CT results with preoperative clinical diagnosis (history, physical examination and laboratory results) to assess whether performing CT altered patient outcome.
This retrospective 5-year study looked at 268 patients. "The overall accuracy rate in diagnosing acute appendicitis preoperatively was 94.7%. There were 39 patients with perforated appendicitis for a perforation rate of 13.8%," they reported.
Focused appendiceal CT with colon contrast was performed in 34% of cases using a soft pediatric rectal tube to administer rectal contrast consisting of 40 mL of gastrografin diluted in 1L of normal saline. CT diagnosis of appendicitis was based on the following criteria: "nonfilling appendix, appendicolith, fat stranding or fluid collection in RLQ, appendix diameter > 6mm, abscess in RLQ."
Results showed that CT had a sensitivity of 94.6%, and the positive predictive value was 95.6% compared with 94.1% for those that did not have CT. They concluded, "preoperative CT did not increase the accuracy in diagnosing appendicitis when compared with patients diagnosed by history, physical examination and laboratory studies."
They stated that a negative CT examination did not exclude acute appendicitis when there was strong clinical evidence for appendicitis. The authors suggested that CT "may play an important role in the evaluation of patients with an atypical clinical presentation or in older girls in whom the diagnosis of appendicitis is more difficult."
The diagnosis of acute appendicitis in a pediatric population: to CT or not to CTStephen, A. et. al.
Department of pediatric surgery, Massachusetts General Hospital, Boston, MA
J Pediatr Surg 2003 March; 38:367-317
By Radiology Review
August 1, 2003
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