Quantitative Brain Magnetic Resonance Imaging in Attention-Deficit Hyperactivity Disorder

Abstract

Background: Anatomic magnetic resonance imaging (MRI) studies of attention-deficit hyperactivity disorder (ADHD) have been limited by small samples or measurement of single brain regions. Since the neuropsychological deficits in ADHD implicate a network linking basal ganglia and frontal regions, 12 subcortical and cortical regions and their symmetries were measured to determine if these structures best distinguished ADHD. Method: Anatomic brain MRIs for 57 boys with ADHD and 55 healthy matched controls, aged 5 to 18 years, were obtained using a 1.5-T scanner with contiguous 2-mm sections. Volumetric measures of the cerebrum, caudate nucleus, putamen, globus pallidus, amygdala, hippocampus, temporal lobe, cerebellum; a measure of prefrontal cortex; and related right-left asymmetries were examined along with midsagittal area measures of the cerebellum and corpus callosum. Interrater reliabilities were.82 or greater for all MRI measures. Results: Subjects with ADHD had a 4.7% smaller total cerebral volume (P=.02). Analysis of covariance for total cerebral volume demonstrated a significant loss of normal right>left asymmetry in the caudate (P=.006), smaller right globus pallidus (P=.005), smaller right anterior frontal region (P=.02), smaller cerebellum (P=.05), and reversal of normal lateral ventricular asymmetry (P=.03) in the ADHD group. The normal age-related decrease in caudate volume was not seen, and increases in lateral ventricular volumes were significantly diminished in ADHD. Conclusion: This first comprehensive morphometric analysis is consistent with hypothesized dysfunction of right-sided prefrontal-striatal systems in ADHD.