Neuroimaging and Neurocognitive Markers of Brain Injury in Young Children with Sickle Cell Disease

Project Summary/Abstract Sickle cell disease (SCD) is an inherited blood disorder with several neurological and developmental complications. Young children with SCD between 2 and 5 years of age, in particular, have an increased risk for ischemic stroke and silent cerebral infarctions (SCI). SCI are hyperintense T2 brain magnetic resonance imaging (MRI) lesions with no accompanying acute neurological symptoms but with associated impaired cognition and increased risk of future progressive or additional stroke/SCI. Neuroimaging and neurocognitive profiles associated with SCI are well established in school-aged and adult SCD populations. This information is largely unknown in young children under 6 years of age with SCD due to risk of sedation/anesthesia with MRI. Our preliminary studies have shown that behavioral training can yield high quality neuroimaging data without sedation in 3 to 4 years old children with SCD through a pilot study. The long term goal of this application is to develop a diagnostic battery using a combination of unsedated neuroimaging measures, neurocognitive testing, and plasma brain injury protein levels to identify young children with SCD at risk for SCI. Through a prospective longitudinal case-control study, we will collect medical history and clinical data and perform neurological examination and blood draws annually in 100 children with SCD from study entry to study exit. Participants will also undergo initial neuroimaging battery at 3 to 4 years of age with repeat neuroimaging at study exit as well as longitudinal neurocognitive testing at study entry, with initial neuroimaging, and with exit neuroimaging. This multi-disciplinary and multi-modality proposal has two Aims. Aim 1 will identify the cross-sectional neuroimaging and neurocognitive findings in 3 to 4 year- old children with SCD and SCI on initial MRI by comparing their results to children with SCD without SCI. Aim 2 will compare longitudinal data from 6 year-old children with and without SCI on exit MRI. Exploratory aims will explore differences in the neuroimaging measures in children on different disease-modifying treatments (hydroxyurea) and plasma protein levels in children with and without SCI. The proposed work will determine which neuroimaging measures and neurocognitive testing may predict SCI, leading to a multi-site study to validate these findings in a larger regionally heterogenous SCD population. The study PI, a neurodevelopmental physician, is an early stage investigator well suited to expand her existing study cohort with support from a team of co-investigators, including a senior behavioral psychologist and neuroimaging physicist, as well as existing collaborators and staff.