Predictive accuracy of standard computed tomography scanning in the diagnosis of Chiari malformation Type I in children.

Abstract

In this study, retrospective data analysis was performed to analyze the utility of head computed tomography (CT) scanning in the diagnosis of Chiari malformation Type I (CM-I) in the pediatric population. The authors conducted a retrospective review of radiology charts describing head CT results obtained at Columbus Children's Hospital between January 2004 and January 2005. The records were searched for the key words "Chiari," "cerebellar ectopy," or "tonsillar ectopy." The exclusion criteria included patients with previously known Chiari malformation Type I or Type II or those who had undergone follow-up magnetic resonance (MR) imaging at other institutions. Head CT and MR images for the remaining patients were reviewed to verify accuracy. Of the 72 patients with suspicious findings of tonsillar ectopy on CT, only 37 (51.4%) had MR imaging findings consistent with CM-I. The tonsillar ectopy in these patients ranged from 3 mm to 17 mm below the foramen magnum. The authors' findings indicate that incidental standard CT scans of the head have limited value in identifying CM-I.