Mapping cortical haemodynamics during neonatal seizures using diffuse optical tomography: A case study

Abstract

Seizures in the newborn brain represent a major challenge to neonatal medicine. Neonatal seizures are poorly classified, under-diagnosed, difficult to treat and are associated with poor neurodevelopmental outcome. Video-EEG is the current gold-standard approach for seizure detection and monitoring. Interpreting neonatal EEG requires expertise and the impact of seizures on the developing brain remains poorly understood. In this case study we present the first ever images of the haemodynamic impact of seizures on the human infant brain, obtained using simultaneous diffuse optical tomography (DOT) and video-EEG with whole-scalp coverage. Seven discrete periods of ictal electrographic activity were observed during a 60 minute recording of an infant with hypoxic–ischaemic encephalopathy. The resulting DOT images show a remarkably consistent, high-amplitude, biphasic pattern of changes in cortical blood volume and oxygenation in response to each electrographic event. While there is spatial variation across the cortex, the dominant haemodynamic response to seizure activity consists of an initial increase in cortical blood volume prior to a large and extended decrease typically lasting several minutes. This case study demonstrates the wealth of physiologically and clinically relevant information that DOT–EEG techniques can yield. The consistency and scale of the haemodynamic responses observed here also suggest that DOT–EEG has the potential to provide improved detection of neonatal seizures.

Long-term continuous monitoring of the preterm brain with diffuse optical tomography and electroencephalography: a technical note on cap manufacturing

“…Austin et al 32 employed a custom-made helmet with whole-head coverage, made of an outer shell of thermoplastic and an inner part of NIR-absorbing foam. Crucially, in all these DOT studies, the length of registration did not exceeded 2 h, with a minimal length of 60 min 6,14 up to a maximum of 115 min 13 and the gestational age ranged from 34 weeks gestation 13 to term. Here, we showed that the adoption of our hand-made cap (NeoCAP) enabled a safe continuous DOT monitoring for a 7-day period in a very preterm infant.…”

“…6,13,[25][26][27][28][29][30][31] Prior studies in this field have raised the issue related to the cap tolerance by the neonates as a possible factor limiting the duration of DOT data acquisition. Singh et al 6 and Chalia et al 13 adopted a soft and flexible cap (EasyCap, Germany, i.e., our outer layer), with a whole-head coverage for a multimodal DOT-EEG acquisition. Ferradal and colleagues 14 employed a custom-made optode holder, composed of five triangular patches joined together with a neoprene headband, fixed to the head via Velcro straps.…”

“…4 Optical imaging is particularly suitable for the (term and preterm) neonatal population, because of its noninvasive nature, portability-it can be used in the neonatal intensive care unit (NICU) at the cradle-side-and technical compatibility with other clinical recording systems. [5][6][7][8][9][10][11][12] For instance, it can be employed in multimodal acquisitions with electroencephalography (EEG), which is used for seizure detection in clinical practice. So far, DOT studies in neonates have monitored hemodynamic changes in the whole brain up to a maximum of 2 h. 6,[13][14][15] Prolonging this "monitoring window" would, however, increase the chance to document important intracranial events in the neonatal population, such as seizures or intracranial hemorrhages.…”

“…[5][6][7][8][9][10][11][12] For instance, it can be employed in multimodal acquisitions with electroencephalography (EEG), which is used for seizure detection in clinical practice. So far, DOT studies in neonates have monitored hemodynamic changes in the whole brain up to a maximum of 2 h. 6,[13][14][15] Prolonging this "monitoring window" would, however, increase the chance to document important intracranial events in the neonatal population, such as seizures or intracranial hemorrhages. 16 The reasons that could explain the limited monitoring time lie primarily in (1) the discomfort of the optode holder for the baby and the skin damage that it can possibly produce and (2) a possible interference of the cap with clinical procedures and nursing.…”

Non-iterative model based image reconstruction of diffuse optical tomography based on DE and RTE in quality control of agricultural product studies

“…Usually, the development of non-destructive evaluation (NDE) based on optical tomography method has been focused on medical application [4,6,8,9]. Nevertheless, NDE OT development on other application is also interesting and promising as described by some researcher on this field [3,14].…”