Ventricular dilatation in ex-prematures: only confined to the occipital region? MRI-based normative standards for 19-year-old ex-prematures without major handicaps.

Background: Premature birth may be associated with white matter injury later developing with widening of the ventricles. However, population-based data on normal ventricular size by age are sparse, making the evaluation of possible ventricular dilatation difficult.
Purpose: To present the linear measurements of the ventricular system, to compare these to subjectively assessed ventricular size, and to examine differences in ventricular size between ex-prematures and controls.
Material and Methods: Eligible survivors (n = 113) from the initial birth cohort (n = 217, born in 1986-1988, birth weight <2000 g) underwent MRI during 2006-2007. One hundred and three were ex-premature and included in the study. The ventricular size was subjectively judged by a pediatric neuroradiologist, and scored as normal, mildly, moderately, or severely dilated. Objective measurements, including width and depth of the frontal and occipital horns, were performed in a blinded fashion, by a pediatric radiologist.
Results: The normative standards for different parts of the ventricular system in ex-premature young adults varied considerably. We found significant associations between the objective measurements and the subjectively classification of ventricular dilatation. Ex-prematures had smaller heads than those born term (control group). After adjustment for head circumference, there were no significant group differences regarding the frontal horns, but the occipital horns were proportionately wider among ex-prematures.
Conclusion: Young adults born prematurely, with a birth weight <2000 g, do not have larger lateral ventricles than healthy controls born term, even after correcting for a smaller head size. However, they do have larger occipital horns, confirming previous studies and strengthening our belief of a specific vulnerability of the occipital region.