Cerebral MRI of very low birth weight children at 6 years of age compared with the findings at 1 year.

BACKGROUND

We have previously reported the results of cerebral MRI examinations in an unselected year cohort of very low birth weight (VLBW) infants at one year of corrected age. Twenty-one (78 %) of 27 infants had abnormal myelination, mainly in the central occipital white matter (COWM) and in the centrum semiovale (CS), seen on T2-weighted images. Twelve infants had irregular and dilated lateral ventricles. We speculated whether these findings indicated perinatal periventricular leukomalacia (PVL). Only two infants had completely normal MRI at age 1 year.

OBJECTIVE

To determine whether the abnormal myelination seen at 1 year of age, was still present, either as delayed myelination or as gliosis caused by perinatal PVL.

MATERIALS AND METHODS

In the present study, we report the results of follow-up cerebral MRI in 20 of these infants at 6 years of age.

RESULTS

Most of the children with MRI deviations at 1 year still had abnormalities at 6 years. Abnormal myelination in the central occipital white matter combined with abnormalities in the CS or with ventricular dilatation at age 1 year, presented as gliosis in 12 of 13 children at 6 years of age. Abnormalities solely in the COWM at age 1 year had normalised in two of five children and persisted as delayed myelination in three at age 6 years. Gliotic changes in periventricular white matter were found in 12 of 20 children (60 %). Areas most affected were the CS (11 children) and the COWM (9 children). Delayed myelination in COWM was found in six children (30 %), combined with gliosis in CS in three children. Twelve infants had ventricular dilatation both at 1 and 6 years of age.

CONCLUSIONS

The MRI correlates of PVL, i. e. gliosis and ventricular dilatation, are common findings on cerebral MRI at 6 years of age in VLBW infants.