White matter alterations in adult with autism spectrum disorder evaluated using diffusion kurtosis imaging

Abstract

Autism spectrum disorder (ASD) has been related to the impairments of white matter (WM) pathways.Recently, a two-compartment model of diffusion kurtosis imaging (DKI) was used to analyze the WM in ASD.However, the model is restricted by some limitations. Our study aimed to demonstrate the first use of a modelfree conventional DKI in the evaluation of WM in ASD and to test the relationship between WM alterations and personality scales. MethodsFifteen subjects with ASD (ASDs) and 15 neurotypical controls (NTs) were scanned on a 3T magnetic resonance (MR) scanner. Personality scales of both groups were measured using autism quotient (AQ), systemizing quotient (SQ), and empathizing quotient (EQ). Multi-shell diffusion-weighted MR data were acquired using two b-values (1000 and 2000 s/mm 2 ). The differences of each DKI indices, i.e., mean kurtosis (MK), radial kurtosis (RK), and axial kurtosis (AK), were evaluated between ASDs and NTs using a tract-based spatial statistics (TBSS). Finally, we also measured the relationships between DKI indices and personality scales. ResultsReduced AK was demonstrated in the body and splenium of corpus callosum of ASDs compared with NTs.There were no significant differences in other indices. Negative correlations were found between AK and AQ or SQ predominantly in WM areas related to social-emotional processing, such as uncinate fasciculus, inferior fronto-occipital fasciculus, and inferior and superior longitudinal fasciculus. ConclusionsA model-free DKI might be used to detect WM alterations in ASDs. Also, DKI indices could be an objective marker to monitor the severity of ASD.

Neurite orientation dispersion and density imaging reveals white matter microstructural alterations in adults with autism

“…Previous studies that used varied approaches to diffusion-weighted imaging data have found evidence for WM microstructural abnormalities in adults with autism in the ATR [ 3 , 4 ], ALIC [ 23 ], CC [ 2 , 4 – 6 , 21 , 22 , 24 , 49 ], cingulum [ 2 , 3 , 21 , 24 ], forceps minor and major [ 21 ], IFOF [ 4 , 21 , 22 , 49 ], ILF [ 3 , 4 , 21 , 22 , 49 ], SLF [ 3 , 4 , 21 – 23 , 49 ], and UF [ 2 – 4 , 21 , 49 ], which is broadly neuroanatomically consistent with our findings. This shows the robustness of the diffusion MRI data analysis pipeline used in the current study.…”

“…Autism is a neurodevelopmental condition characterized by social communication and interaction deficits and the presence of restricted and repetitive patterns of behaviors, interests, or activities [ 1 ]. Evidences suggesting the association between behavioral anomalies in autism and white matter (WM) microstructural alterations that persist until adult life are increasing [ 2 – 6 ]. Although the pathophysiological causes of autism are not yet fully understood, recent postmortem studies support the view that neuronal loss [ 7 , 8 ] and neuroinflammation [ 9 , 10 ] contribute to autism etiology.…”

“…In the current study, we employed NODDI (1) to assess differences in the WM microstructure integrity in adults with autism compared with typically developing (TD) individuals; (2) to define more specific causes of WM microstructural alterations in autism by hypothesizing that NODDI might resolve component pathologies of autism in the WM, such as neuronal loss or neuroinflammation, in order to overcome DTI limitations; and (3) to determine if these WM properties are associated with autism-related scores. Most previous studies in adults with autism have focused on evaluating the changes in the microstructure of WM [ 6 , 21 – 24 ] or the morphology of GM [ 25 – 27 ]; however, the relationship between the different brain regions and autism remain unclear. In addition, GM structural analysis was also performed to observe the association between WM microstructural alterations measured using NODDI and GM structural changes.…”

Diffusion Magnetic Resonance Imaging-Based Biomarkers for Neurodegenerative Diseases

“…DKI describes the state of brain tissue using three kurtosis metrics: mean kurtosis (MK), axial kurtosis (AK), and radial kurtosis (RK). DKI has been used to evaluate neurodegeneration in WM with complex structures, including voxels containing crossing fibers [ 12 , 35 , 36 , 37 ]. Moreover, DKI parameters reflect the restriction of water diffusion in anisotropic as well as isotropic environments compared to DTI parameters, which assume non-restriction of water diffusion; therefore, the utility of DKI has also been demonstrated for the evaluation of microstructural changes in GM, which is composed primarily of neuronal cell bodies and exhibits isotropic water diffusion [ 20 , 28 , 38 , 39 ].…”

Association of Reduced Tract Integrity with Social Communication Deficits in Preschool Autism Children: A Tract-Based Spatial Statistics Study

“…One possible explanation for this finding is that the arcuate and temporoparietal tracts mature in later childhood, and the younger age of our participants may have not allowed us to observe this maturation yet. Furthermore, the corpus callosum (CC) plays an important role in the lateral asymmetry of brain function [26][27][28][29] as the main transverse fibers between bilateral cerebral hemispheres. Abnormal development of the CC may affect the integration and communication of information between the hemispheres, affecting cognitive function in ASD.…”