Functional MRI of visual cortex in sedated 18 month-old infants with or without periventricular leukomalacia

Functional MRI (fMRI) of the visual cortex was evaluated in 42 sedated 18-m onth-old infants (mean corrected age; 31 males, 11 females) with or without periventricular leukomalacia (PVL), Data from 14 infants could not be eval uated because of movement artefacts. Ten of the remaining 28 infants showed no significant fMRI response upon visual stimulation, In 18 infants, a sig nificant signal change upon stimulation was found in the visual cortex: in 17 a signal decrease and in one a signal increase, Functional changes were located mainly in the anterior part of the visual cortex. Seven of the 28 i nfants had normal MRI and 21 showed variable occipital PVL, An fMRI respons e was equally frequent in infants without PVL 14 of 7 infants) and with PVL (14 of 21 infants). In conclusion, fMRI was shown to be feasible in sedate d infants. No correlation was found between functional activation and the p resence or absence of occipital PVL, Type of fMRI response (signal decrease ) and localization (anterior part of the visual cortex) are different from those seen in adults, probably reflecting a combination of sedation effects and immaturity of the visual system. At present, fMRI is a highly promisin g research tool; its clinical relevance still has to be established.