NEONATAL SOCIETY ABSTRACTS
Diffuse white matter abnormalities on magnetic resonance imaging of the brain in preterm infants at term and neurodevelopmental outcome
Presented at the Neonatal Society 2004 Summer Meeting (programme).
Dyet LE1, Kennea NL1, Counsell S2, Duggan P1, Allsop J2, Maalouf E1, Rutherford MA2, Edwards AD1,2, Cowan F1
1 Department of Paediatrics, Imperial College Faculty of Medicine,
Hammersmith Hospital, London W12 0NN, UK
2 Imaging Sciences Department, MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, Hammersmith Hospital, London W12 0NN, UK
Introduction: Diffuse Excessive High Signal Intensity (DEHSI) in the white matter on T2 weighted magnetic resonance (MR) imaging of the brain is present in approximately 75% of preterm infants at term corrected age (1). MR diffusion imaging suggests that DEHSI represents abnormality (2), and this is supported by its absence in normal term born infants. It is therefore important to investigate whether DEHSI impacts on later neurodevelopmental outcome.
Aim: To investigate the relationship between DEHSI on T2 weighted brain MR imaging in preterm infants at term and their subsequent neurodevelopmental outcome.
Methods: Infants were recruited from a consecutive cohort born at the Hammersmith Hospital at < 30 weeks gestation, who underwent serial brain MR imaging between birth and term. The Hammersmith Hospitals Research Ethics Committee approved the study. Infants with brain imaging at term and a neurodevelopmental assessment at 2 years corrected age were eligible for this part of the study. Infants with focal cerebral lesions known to be associated with a poor neurodevelopmental outcome were excluded from further analysis; these included haemorrhagic parenchymal infarction, cystic periventricular leucomalacia and cerebellar haemorrhage. The MR images were analysed by 2 independent investigators and categorized as having normal white matter, DEHSI or severe DEHSI on the basis of the degree of signal abnormality. The Developmental Quotient (DQ) was calculated at 2 years corrected age using Griffiths Mental Development Scales (Revised). The relationship between DQ and DEHSI was analysed using Analysis of Variance with correction for gestational age.
Results: 57 preterm infants were scanned at term and had a neurodevelopmental assessment at 2 years corrected age. 11 were excluded from further analysis because of associated cerebral lesions. 34 (74%) of the remaining infants had DEHSI on their MR scan at term and 6 of these were classified as severe. There was complete concordance between the 2 investigators for the classification of DEHSI. The presence of DEHSI was not related to gestational age at birth (p=0.7). The mean (range) DQ in the 3 groups was 111 (91-154) for normal white matter, 94 (67-129) for DEHSI and 92 (84-106) for severe DEHSI. The presence and severity of DEHSI was significantly related to a decreased DQ on neurodevelopmental assessment (p=0.02).
Conclusion: The presence of DEHSI in the white matter on T2 weighted brain MR imaging in the preterm infant at term is related to impaired neurodevelopmental outcome. However, the aetiology and pathology underlying DEHSI remains unknown.
1. Maalouf E et al, J Pediatr 1999; 135: 351-357
2. Counsell S et al, Pediatrics 2003; 112: 1-7