Neuroimaging in Attention-Deficit/Hyperactivity Disorder: Recent Advances
Fatemeh Dehghani Firouzabadi, Sara Ramezanpour, Mohammad Dehghani Firouzabadi, Ilyssa J. Yousem, Nicolaas A. J. Puts, David M. Yousem
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition that leads to impaired attention and impulsive behaviors diagnosed in, but not limited to, children. ADHD can cause symptoms throughout life. This article summarizes the structural (conventional, volumetric, and diffusion tensor imaging) and functional (task-based functional MRI [fMRI], resting-state fMRI, PET, and MR spectroscopy) brain findings in patients with ADHD. Consensus is lacking regarding altered anatomic or functional imaging findings of the brain in children with ADHD, likely because of the heterogeneity of the disorder. Most anatomic studies report abnormalities in the frontal lobes, basal ganglia, and corpus callosum; decreased surface area in the left ventral frontal and right prefrontal cortex; thinner medial temporal lobes; and smaller caudate nuclei. Using fMRI, researchers have focused on the prefrontal and temporal regions, reflecting perception-action mapping alterations. Artificial intelligence models evaluating brain anatomy have highlighted changes in cortical thickness and the shape of the inferior frontal cortex, bilateral sensorimotor cortex, left temporal lobe, and insula. Early intervention and/or normal brain maturation can alter imaging patterns and convert functional imaging studies to a normal pattern. Although imaging findings provide insight into the neuropathophysiology of the disease, no definitive structural or functional pattern defines the disorder from a neuroradiologic perspective.