Brain T 1 in young children with sickle cell disease: evidence of early abnormalities in brain development

Measurement of tissue spin lattice relaxation time (T 1 ) has been used to characterize brain development in healthy children. Here we report the first study of brain T 1 in young children with sickle cell disease (SCD). The T 1 in 10 tissue samples was measured by established techniques; 46 SCD patients under the age of 4 years were compared to 267 controls, including 55 well children under the age of 4 years. A model was developed to predict the relationship between age and brain T 1 in controls, then we compared patient T 1 to healthy normal T 1. Most white matter and gray matter tissues in infant patients (<2 years old), had T 1 values significantly higher than normal. For example, 15.0% of patient caudate T 1 values were above the upper bound of the 95% confidence interval for controls, but only 2.5% of normal values are expected to be this high ( p = 0.0003). Among infant patients, brain T 1 was significantly higher than normal in every tissue ( p < 0.01) except cortical gray matter. However, patient T 1 values declined rapidly to values lower than normal by about age 4. Our findings imply that patients follow an abnormal developmental trajectory beginning early in infancy.