Preliminary evidence of altered gray and white matter microstructural development in the frontal lobe of adolescents with attention‐deficit hyperactivity disorder: A diffusional kurtosis imaging study

Abstract

Purpose To investigate non-Gaussian water diffusion using diffusional kurtosis imaging (DKI) to assess age effects on gray matter (GM) and white matter (WM) microstructural changes in the prefrontal cortex (PFC) of adolescents with attention-deficit hyperactivity disorder (ADHD) compared to typically developing controls (TDC). Materials and Methods In this preliminary cross-sectional study, T1-weighted magnetization-prepared rapid gradient echo (MPRAGE) and DKI images were acquired at 3T from TDC (n = 13) and adolescents with ADHD (n = 12). Regression analysis of the PFC region of interest (ROI) was conducted. Results TDC show a significant kurtosis increase of WM microstructural complexity from 12 to 18 years of age, particularly in the radial direction, whereas WM microstructure in ADHD is stagnant in both the axial and radial directions. In ADHD, GM microstructure also lacked a significant age-related increase in complexity as seen in TDC; only kurtosis measures were able to detect this difference. Conclusion These findings support the prevailing theory that ADHD is a disorder affecting frontostriatal WM. Our study is the first to directly quantify an aberrant age-related trajectory in ADHD within GM microstructure, suggesting that the assessment of non-Gaussian directional diffusion using DKI provides more sensitive and complementary information about tissue microstructural changes than conventional diffusion imaging methods.

Frontal Lobe Epilepsies: Neuropsychological and Behavioral Consequences in Children

“…This indicates that FLE children have an impaired sensitivity to the chances of a distractor appearing and are consequently less able to resist this interference, suggesting that impairments involving frontal regions reduce the individual's ability to prepare to focus their attention on the upcoming target. Deficits in attention skills are consistent with clinical observations in children with frontal lobe injuries of different aetiology, such as tumour, stoke, cerebral marfomations, trauma (Jacobs et al, 2007), and also with imaging studies showing a reduced activation in the frontal cortex in patients with attention deficit disorder (Helpern et al, 2011). Another important function of the executive domain is cognitive flexibility.…”

Diffusional Kurtosis Imaging of the Developing Brain

“…32 It has already been shown to yield valuable information about the microstructural integrity of the brain in children with epilepsy 33 and in adolescents with attention deficit/hyperactivity disorder. 34 Indeed, future DKI studies may explore the sensitivity of kurtosis metrics to pathologies that alter the microstructural complexity in the developing brain.…”

Visualizing Non-Gaussian Diffusion: Clinical Application of q-Space Imaging and Diffusional Kurtosis Imaging of the Brain and Spine

“…Using DKI measurements, Helpern's group reported less development of the frontal white matter in patients with attention-deˆcit hyperactivity disorder than in typically developing controls. 51 In addition, gray matter microstructure also lacked the signiˆcant age-related increase in complexity seen in controls; only kurtosis measures could detect this diŠerence. Therefore, the authors concluded that DKI provides information about changes in tissue microstructure that is more sensitive than and complementary to that provided by conventional diŠu-sion imaging methods.…”

“…In contrast, the use of DKI to evaluate structural changes in gray matter has been reported in relatively small numbers of subjects. 51,52 Therefore, DKI may be useful in the evaluation of NAGM in patients with multiple sclerosis. Brain MR imaging demonstrated multiple cerebral infarctions, including a subacute lesion in the right frontal deep white matter, which appeared as a high signal on diŠusion-weighted imaging (DWI) (a) and a low signal on the calculated apparent diŠusion coe‹cient (ADC) map (b).…”