44 White Matter Abnormality is Associated with Volume Reduction in Deep Grey Nuclei Following Preterm Birth

Abstract

Background. Diffuse white matter disease, which can be seen on MRI as Diffuse Excessive High Signal Intensity (DEHSI) and quantified using apparent diffusion coefficient (ADC) values is the most common abnormality in preterm infants at term equivalent age. We used a computational anatomic approach to survey the brain for structural alterations associated diffuse white matter disease.Methods. Subjects: 62 preterm infants without parenchymal cerebral lesions, born at median 29.7 weeks GA were studied at term equivalent age (median 40.4 weeks GA) together with 12 term born controls. Image acquisition: A 1.5 Tesla MR system was used to acquire high resolution T1-weighted volume datasets with a voxel size 1x1x1.6mm, in addition to conventional and diffusion weighted imaging. Diffuse white matter disease was defined as ADC values > 2 standard deviations above the mean of the control group in one or more white matter region. Image processing: non-rigid image registration was used to transform all images to a reference subject, and voxel-wise volume change values extracted from transformations were analysed with a correction for multiple comparisons.Results. Preterm infants showed volume loss within lentiform and thalamic nuclei (p<0.05), particularly among infants with diffuse white matter disease (p<0.05) and with increasing prematurity at birth (p<0.05), but ADC values in the thalamus and lentiform nuclei were similar to controls.Conclusions. Growth failure within deep grey nuclei occurs in association with diffuse white matter disease and without evidence of acute injury. This suggests deep grey matter connectivity is altered by preterm birth.