Evidence of lower myelin content in selective white matter tracts of OCD children/adolescents using a myelin water imaging approach

Motivation: White matter tracts have been implicated in pediatric OCD by DTI studies; however, the interpretation of DTI-derived indices regarding attributes of WM microstructure is limited and poorly understood. Goal(s): To identify group differences and age effects on MWI metrics (MWF and geomT2IEW) across WM tracts in pediatric OCD compared to controls. Approach: MWF and geomT2IEW across 5 WM tracts were assessed in 33 OCD and 58 HC. Results: Significantly lower myelin content was observed in association fibers in OCD compared to HC. Age effects were observed for MWF in projection/association fibers reflecting a lack of progressive increasing MWF values with age in OCD. Impact: Compared to healthy individuals, OCD children/adolescents show deficits in myelin content in association fibers, as well as evidence suggesting a lack of progressive maturation of both (anterior) projection and association fibers in pediatric OCD, which warrants longitudinal studies.