Preterm birth frequently involves white matter injury and affects long-term neurologic and cognitive outcomes. Diffusion tensor imaging has been used to show that the white matter microstructure of newborn, preterm children is compromised in a regionally specific manner. However, until now it was not clear whether these lesions would persist and be detectible on longterm follow-up. Hence, we collected diffusion tensor imaging data on a 1.5-T scanner, and computed fractional anisotropy and coherence measures to compare the white matter integrity of children born preterm to that of control subjects. The subjects for the preterm group (10.9 Ϯ 0.29 y; n ϭ 9; birth weight Յ 1500 g; mean gestational age, 28.6 Ϯ 1.05 wk) possessed attention deficits, a common problem in preterms. They were compared with age-and sex-matched control children (10.8 Ϯ 0.33 y; n ϭ 10; birth weight Ն 2500; gestational age, Ն 37 wk). We found that the preterm group had lower fractional anisotropy values in the posterior corpus callosum and bilaterally in the internal capsules. In the posterior corpus callosum this difference in fractional anisotropy values may partially be related to a difference in white matter volume between the groups. An analysis of the coherence measure failed to indicate a group difference in the axonal organization. These results are in agreement with previous diffusion tensor imaging findings in newborn preterm children, and indicate that ex-preterm children with attention deficits have white matter disturbances that are not compensated for or repaired before 11 y of age. Preterm birth, and the early exposure to the extrauterine environment, increases the risks of perinatal brain injury (1, 2). Often these injuries involve the white matter (2, 3) and affect long-term neurologic and cognitive outcome, including problems with attention (4 -8). These long-term effects of perinatal complications are either a result of the inability to repair the original lesions, such as PVL, or caused by a disruption of the maturational processes.DTI is a relatively recent method of MRI. From the fact that the preferential direction of water diffusion within the white matter of the brain occurs along the axons, this technique identifies white matter and indicates the direction of the fiber bundles within (9). In the absence of restriction, water diffusion is spatially uniform (i.e. isotropic). However, depending on the number, size, arrangement, and density of axons, as well as on the extent of myelination, water diffusion in the brain deviates from spherical and approaches the shape of an ellipsoid (i.e. anisotropic diffusion) with the long axis pointing along the axons [for a review, see Westin et al. (10)]. Therefore DTI provides information on the microstructure of white matter. To estimate the extent of anisotropy we calculated FA, which ranges in value between 0 and 1 for isotropic and onedimensional diffusion, respectively (11).Several studies have used conventional MRI to investigate the immediate effects of brain injury in prete...
