Detecting corpus callosum abnormalities in autism based on anatomical landmarks.

Autism is a severe developmental disorder whose neurological basis is largely unknown. The aim of this study was to identify the shape differences of the corpus callosum between patients with autism and control subjects. Anatomical landmarks were collected from midsagittal magnetic resonance images of 25 patients and 18 controls. Euclidean distance matrix analysis and thin-plate spline analyses were used to examine the landmark forms. Point-by-point shape comparison was performed both globally and locally. A new local shape comparison scheme was proposed which compared each part of the shape in its local coordinate system. Point correspondence was established among individual shapes based on the inherent landmark correspondence. No significant difference was found in the landmark form between patients and controls, but the distance between the interior genu and the posterior-most section was found to be significantly shorter in patients. Thin-plate spline analysis showed significant group differences between the landmark configurations in terms of the deformation from the overall mean configuration. Significant global shape differences were found in the anterior lower body and posterior bottom, and there was a local shape difference in the anterior bottom. This study can serve as both a clinical reference and a detailed procedural guideline for similar studies in the future.