Tractography of white-matter tracts in very preterm infants: a 2-year follow-up study

Aim The aim of this study was to determine whether tractography of white-matter tracts can independently predict neurodevelopmental outcome in very preterm infants. Method Out of 84 very preterm infants admitted to a neonatal intensive care unit, 64 (41 males, 23 females; median gestational age 29.1weeks [range 25.631.9]; birthweight 1163g [range 5851960]) underwent follow-up at 2years. Diffusion tensor imaging (DTI) values obtained around term were associated with a neurological examination and mental and psychomotor developmental index scores at 2years based on the Bayley Scales of Infant Development (version 3). Univariate and logistic regression analyses tested for associations between DTI values and follow-up parameters. Cut-off values predicting motor delay and cerebral palsy (CP) were determined for fractional anisotropy, apparent diffusion coefficient (ADC), and fibre lengths. Results Infants with psychomotor delay and CP had significantly lower fractional anisotropy values (p=0.002, p=0.04 respectively) and shorter fibre lengths (p=0.02, p=0.02 respectively) of the posterior limb of the internal capsule. Infants with psychomotor delay also had significantly higher ADC values (p=0.03) and shorter fibre lengths (p=0.002) of the callosal splenium. Fractional anisotropy values of the posterior limb of the internal capsule independently predicted motor delay and CP, with sensitivity between 80 and 100% and specificity between 66 and 69%. ADC values of the splenium independently predicted motor delay with sensitivity of 100% and specificity of 65%. Interpretation Diffusion tensor imaging tractography at term-equivalent age independently predicts psychomotor delay at 2years of age in preterm infants.