In the largest sample studied to date, white matter microstructural trajectories and their relation to persistent symptoms were examined after pediatric mild traumatic brain injury (mTBI). This prospective, longitudinal cohort study recruited children aged 8-16.99 years with mTBI or mild orthopedic injury (OI) from five pediatric emergency [Correction added on 04 May 2022, after first online publication: Quynh Doan's affiliation is updated and subsequent affiliations were re-numbered.]

Background: Motion can compromise image quality and confound results, especially in pediatric research. This study evaluated qualitative and quantitative approaches to motion artifacts detection and correction, and whether motion artifacts relate to injury history, age, or sex in children with mild traumatic brain injury or orthopedic injury relative to typically developing children. The concordance between qualitative and quantitative motion ratings was also examined.Method: Children aged 8-16 years with mild traumatic brain injury (n=141) or orthopedic injury (n=73) were recruited from the emergency department and completed an MRI scan roughly 2 weeks post-injury.Typically developing children (n=41) completed a single MRI scan. T1-and diffusion-weighted images were visually inspected and rated for motion artifacts by trained examiners. Quantitative estimates of motion artifacts were derived from FreeSurfer and FSL.Results: Age (younger > older) and sex (boys > girls) were signi cantly associated with motion artifacts on both T1-and diffusion-weighted images. Children with mild traumatic brain or orthopedic injury had signi cantly more motion-corrupted diffusion-weighted volumes than typically developing children, but mild traumatic brain injury and orthopedic injury groups did not differ from each other. The exclusion of motion-corrupted volumes did not signi cantly change diffusion tensor imaging metrics.Discussion: Results indicate that automated quantitative estimates of motion artifacts, which are less labour-intensive than manual methods, are appropriate. Results have implications for the reliability of structural magnetic resonance imaging research and highlight the importance of considering motion artifacts in studies of pediatric mild traumatic brain injury.

Highlights We examined white matter microstructure after pediatric mTBI using NODDI and DTI. Children with mTBI did not significantly differ from those with OI on any metrics. Minor alterations, if any, may be present in children at the post-acute stage after mTBI. Large longitudinal studies are needed to understand long-term brain changes post injury.

Background: Motion can compromise image quality and confound results, especially in pediatric research. This study evaluated qualitative and quantitative approaches to motion artifacts detection and correction, and whether motion artifacts relate to injury history, age, or sex in children with mild traumatic brain injury or orthopedic injury relative to typically developing children. The concordance between qualitative and quantitative motion ratings was also examined.Method: Children aged 8-16 years with mild traumatic brain injury (n=141) or orthopedic injury (n=73) were recruited from the emergency department and completed an MRI scan roughly 2 weeks post-injury. Typically developing children (n=41) completed a single MRI scan. T1- and diffusion-weighted images were visually inspected and rated for motion artifacts by trained examiners. Quantitative estimates of motion artifacts were derived from FreeSurfer and FSL. Results: Age (younger > older) and sex (boys > girls) were significantly associated with motion artifacts on both T1- and diffusion-weighted images. Children with mild traumatic brain or orthopedic injury had significantly more motion-corrupted diffusion-weighted volumes than typically developing children, but mild traumatic brain injury and orthopedic injury groups did not differ from each other. The exclusion of motion-corrupted volumes did not significantly change diffusion tensor imaging metrics. Discussion: Results indicate that automated quantitative estimates of motion artifacts, which are less labour-intensive than manual methods, are appropriate. Results have implications for the reliability of structural magnetic resonance imaging research and highlight the importance of considering motion artifacts in studies of pediatric mild traumatic brain injury.