Presented at the Neonatal Society 2002 Autumn Meeting.
Shanmugalingam S1 (Introduced by Professor J S Wyatt), Bainbridge A2, Thornton J2, Priest A2, Iwata O1, Cady E2, Ordidge R2, Wyatt JS1
1 Department of Paediatrics, University College London, UK
2 Department of Medical Physics and Bioengineering, University College London, UK
Purpose of study: To investigate the correlation between apparent diffusion coefficient (ADC) of brain water with neurodevelopmental outcome at one year in infants with suspected perinatal hypoxic- ischaemic encephalopathy.
Subjects: 15 term infants with mean corrected gestational age at scan (CGA) 40.2 +/- 2.2 weeks; median post natal age at scan (PA) 4 days (range 1-51 days) were studied. All subjects demonstrated clinical signs of encephalopathy and had a history consistent with perinatal hypoxia- ischaemia.
Methods: All infants had a modified Amiel-Tison (AT) neurological assessment daily for the first week of life. An imaging slice was selected so as to intersect the basal ganglia. Regions of interest were defined as listed in the table and mean grey and white matter values were calculated. An AT neurological assessment and a Griffiths developmental assessment were performed at one year and subjects were divided into three outcome groups.
Results: Data presented as: group mean (standard deviation).
*p<0.05; ANOVA. T=thalamus; BG=basal ganglia;
PWM, OWM, FWM =parietal, occipital, frontal white matter;
DGM/WM = average deep grey/white matter
Conclusion: Group averaged ADC shows significant differences between normal and severe groups in both DGM and WM. Although global ischaemia is known to cause DGM injury, the WM data appears to be more specific in predicting outcome. The initial drop in ADC normalises in the days after injury and there is tentative evidence in the literature that this process is slower in WM than in DGM in neonates (1,2). Plotting the above data against PA gives a suggestion of this trend and may explain why, at median PA of 4 days, the WM data shows more specificity than the DGM data. Clearly, understanding the time-course of ADC evolution is crucial in interpreting data of this kind.
References
1. Robertson et al; AJNR 1999; 20; 1658-1670.
2. Soul et al; Pediatrics 2002; 108; 1211-1213.