Accuracy of ultrasonography versus computed tomography scan in detecting parapharyngeal abscess in children

Significant morbidity and rarely mortality have been described in parapharyngeal space infections in children; hence, the decision on the timing of surgical intervention might be crucial. The aim of this study was to compare the accuracy of plain x-rays, ultrasonography (US), and contrast-enhanced computed tomography (CT) in demonstrating a parapharyngeal abscess.

A retrospective study on all patients with parapharyngeal abscess admitted and operated on from January 1996 to December 2000 was carried out. Charts were reviewed for patients' demographics, symptoms and signs, details of workup, intraoperative findings, and culture results. The CT scans were reviewed for the presence of a rim enhancement, a presence of a definable wall, and fluid-fluid level and were correlated with the plain x-rays and US results and intraoperative findings.

Eighteen patients with proven parapharyngeal infection were included: 10 with proven abscess and 8 with cellulitis. The sensitivity and specificity of lateral neck radiograph and US were low compared with a specificity of 87.5 while evaluating fluid-fluid level seen on the CT scan, sensitivity of 58.3% for the presence of a definable abscess wall, and a sensitivity of 100% for the presence of a prominent wall.

Our study demonstrates good rates of accuracy of CT scan for diagnosing a parapharyngeal abscess. Our study suggest that it is appropriate to obtain a CT scan upon presentation in all children with suspected parapharyngeal abscess and that a CT scan is proven to be a useful diagnostic tool in establishing a treatment plan.