Early brain overgrowth in autism associated with an increase in cortical surface area before age 2 years.

Context: Brain enlargement has been observed in 2-year-old children with autism, but the underlying mechanisms are unknown.

Objective: To investigate early growth trajectories in brain volume and cortical thickness.

Design: Longitudinal magnetic resonance imaging study.

Longitudinal study of amygdala volume and joint attention in 2- to 4-year-old children with autism.

Context: Cerebral cortical volume enlargement has been reported in 2- to 4-year-olds with autism. Little is known about the volume of subregions during this period of development. The amygdala is hypothesized to be abnormal in volume and related to core clinical features in autism.

Corpus callosum subdivision based on a probabilistic model of inter-hemispheric connectivity.

Statistical shape analysis has become of increasing interest to the neuroimaging community due to its potential to locate morphological changes. In this paper, we present the a novel combination of shape analysis and Diffusion Tensor Image (DTI) Tractography to the computation of a probabilistic, model based corpus callosum (CC) subdivision. The probabilistic subdivision is based on the distances of arc-length parameterized corpus callosum contour points to trans-callosal DTI fibers associated with an automatic lobe subdivision.

User-guided 3D active contour segmentation of anatomical structures: significantly improved efficiency and reliability.

Active contour segmentation and its robust implementation using level set methods are well-established theoretical approaches that have been studied thoroughly in the image analysis literature. Despite the existence of these powerful segmentation methods, the needs of clinical research continue to be fulfilled, to a large extent, using slice-by-slice manual tracing. To bridge the gap between methodological advances and clinical routine, we developed an open source application called ITK-SNAP, which is intended to make level set segmentation easily accessible to a wide range of users, including those with little or no mathematical expertise.

Magnetic resonance imaging and head circumference study of brain size in autism: birth through age 2 years.

Context: While the neuroanatomical basis of autism is not yet known, evidence suggests that brain enlargement may be characteristic of this disorder. Inferences about the timing of brain enlargement have recently come from studies of head circumference (HC).

Objectives: To examine brain volume and HC in individuals with autism as compared with control individuals.

Cortical gray and white brain tissue volume in adolescents and adults with autism.

Background: A number of studies have found brain enlargement in autism, but there is disagreement as to whether this enlargement is limited to early development or continues into adulthood. In this study, cortical gray and white tissue volumes were examined in a sample of adolescents and adults with autism who had demonstrated total brain enlargement in a previous magnetic resonance imaging (MRI) study.

Methods: An automated tissue segmentation program was applied to structural MRI scans to obtain volumes of gray, white, and cerebrospinal fluid (CSF) tissue on a sample of adolescent and adult males ages 13-29 with autism (n = 23) and controls (n = 15).