Incidental Magnetic Resonance Imaging (MRI) Findings in Young Children with Autism

Background: Data on incidental MRI findings in young children is only recently beginning to be seriously evaluated (Kim et al., 2002). Despite the fact that there have been a number of MRI studies of very young individuals with autism, there have been no reports on the rate of incidental findings encountered in these studies. Interestingly, polymicrogyria and macrogyria have been reported in adults with autism (Piven 1990). In the context of a large scale MRI study of young children (2-4-years-old), we have encountered several incidental findings. We have endeavored, therefore, to more systematically evaluate the occurrence of incidental findings in our study sample.

Objectives: To evaluate the rate of significant incidental MRI findings in young children (2-4-years-old) with autism relative to typically developing controls.

Methods: Structural MRIs have been acquired in 107 children (73 autism spectrum disorders [ASD], 34 typical development [TD]) ages 27-56 months (mean 40 months). Exclusionary criteria were limited only to those with a contraindication for MRI.  Retrospective clinical evaluations of the MRI scans have been carried out by a pediatric neuroradiologist blind to subject diagnosis.

Results: Significant incidental findings occur at a higher rate in children with autism spectrum disorders than in typically developing controls. Examples of significant incidental findings include Dandy-Walker Syndrome variants, ventriculomegaly, Chiari I malformations, and global cortical atrophy. We will present types and statistical evaluations of the occurrence of incidental findings of all children in this ongoing MRI study.

Conclusions: Incidental findings with significant clinical implications have been detected in a larger proportion of children with autism than in age-matched typically developing children. This raises the prospect that there may be clinical benefit to conducting routine MRIs in children diagnosed with autism.