Structural correlates of preterm birth in the adolescent brain.
OBJECTIVE
The Stockholm Neonatal Project involves a prospective, cross-sectional, population-based, cohort monitored for 12 to 17 years after birth; it was started with the aim of investigating the long-term structural correlates of preterm birth and comparing findings with reports on similar cohorts.


METHODS
High-resolution anatomic and diffusion tensor imaging data measuring diffusion in 30 directions were collected by using a 1.5-T MRI scanner. A total of 143 adolescents (12.18-17.7 years of age) participated in the study, including 74 formerly preterm infants with birth weights of <or=1500 g (range: 645-1486 g) and 69 term control subjects. The 2 groups were well matched with respect to demographic and socioeconomic data. The anatomic MRI data were used for calculation of total brain volumes and voxelwise comparison of gray matter (GM) volumes. The diffusion tensor imaging data were used for voxelwise comparison of white matter (WM) microstructural integrity.


RESULTS
The formerly preterm individuals possessed 8.8% smaller GM volume and 9.4% smaller WM volume. The GM and WM volumes of individuals depended on gestational age and birth weight. The reduction in GM could be attributed bilaterally to the temporal lobes, central, prefrontal, orbitofrontal, and parietal cortices, caudate nuclei, hippocampi, and thalami. Lower fractional anisotropy was observed in the posterior corpus callosum, fornix, and external capsules.


CONCLUSIONS
Although preterm birth was found to be a risk factor regarding long-term structural brain development, the outcome was milder than in previous reports. This may be attributable to differences in social structure and neonatal care practices.
Neonatal Units, Department of Woman andChild Health, Karolinska Institute, Stockholm, Sweden. zoltan.nagy@ki.se
Zoltan
Z
Nagy
John
J
Ashburner
Jesper
J
Andersson
Saad
S
Jbabdi
Bogdan
B
Draganski
Stefan
S
Skare
Birgitta
B
Böhm
Ann-Charlotte
AC
Smedler
Hans
H
Forssberg
Hugo
H
Lagercrantz
D000293:Adolescent; D001724:Birth Weight; D001921:Brain / Q000033:anatomy & histology* / Q000254:growth & development; D002648:Child; D015331:Cohort Studies; D056324:Diffusion Tensor Imaging; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008137:Longitudinal Studies; D009929:Organ Size; D047928:Premature Birth