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

Abstract

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 29.1 weeks [range 25.6-31.9]; birthweight 1163 g [range 585-1960]) underwent follow-up at 2 years. Diffusion tensor imaging (DTI) values obtained around term were associated with a neurological examination and mental and psychomotor developmental index scores at 2 years 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 2 years of age in preterm infants.