Presented at the Neonatal Society 2015 Autumn Meeting.
Chalia M1,2, Cooper R1,4, Lee CW1,2, Dempsey L1,4, Edwards A1,2, Michell A1,3, Brigadoi S1,4, Everdell N1,4, Hebden J1,4, Austin T1,2
1 neoLAB, The Evelyn Perinatal Imaging Centre, Cambridge University Hospitals NHS Foundation Trust
2 Department of Neonatology, Cambridge University Hospitals NHS Foundation Trust
3 Department of Clinical Neurophysiology, Cambridge University Hospitals NHS Foundation Trust
4 Department of Medical Physics and Biomedical Engineering, University College London
Background: The aim of this prospective study was to explore the neurovascular coupling of these abnormal EEG states in term neonates with HIE and to provide valuable data to support the significance of combined DOI-EEG in newborn brain monitoring.
Methods: Twenty-three infants with HIE following informed parental consent, were recruited from the Neonatal Intensive Care Unit of the Rosie Hospital, Cambridge. The NTS DOI system (developed in University College London) coupled to a video EEG was used to scan each infant during therapeutic hypothermia. Spectral analysis of the EEG data was performed followed by independent review by a Clinical Neurophysiologist. The data were further analysed and optical density changes were converted to those of total, oxy- and deoxy-haemoglobin concentrations using the modified Beer-Lambert law. By using a standard deconvolution approach the haemodynamic response to electrographic burst activity could be isolated. Based on this analysis and the “timeresolved optical absorption and scatter tomography” (TOAST) (3) software package images demonstrating this haemodynamic event were reconstructed.
Results: Eight patients demonstrated burst suppression or discontinuous EEG pattern during scanning. All infants had required anticonvulsant medications. Two subjects were excluded due to poor optical trace. The cortical haemodynamic relation to the mean average of burst durations was studied. At the bursts’ onset there is a small decrease in the total and oxy-haemoglobin concentration followed by a rapid increase and subsequent recovery to the baseline concentrations. The duration and scale of this, is variable amongst subjects, yet consistent and the response apparent across the cortex. Images created based on the vascular activity associated with burst activity demonstrate a temporal and spatial distribution of the response across the cortex. In particular for one of the subjects, the area of maximum haemodynamic changes was associated with haemorrhagic and oedematous cerebral injury seen on the infants subsequent MRI.
Conclusion: The results obtained to date have shown a completely novel haemodynamic phenomenon associated with electrical abnormalities in the brain with a high degree of spatial resolution. It is also demonstrated that optical topography with EEG is a powerful, reliable, safe and non-invasive tool for monitoring sick neonates.
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1. Volpe , Neurology of the Newborn, 2001; 497-520
2. Japaritze, et al, PLoS One, 2015; 10(4):e0123807
3. Schweiger, et al., J Biomed Opt. 2014;19(4):040801