Electrode configurations for detection of intraventricular haemorrhage in the premature neonate

Abstract

Intraventricular haemorrhage is a common cause of death in premature human infants. As preventative measures and treatments become available, a method for monitoring and detection is required. Electrical impedance tomography (EIT) is a viable monitoring method compared to modalities such as ultrasound, MRI or CT because of its low cost and contrast sensitivity to blood. However, its sensitivity to blood may be obscured by the low conductivity skull, high conductivity cerebrospinal fluid (CSF) and shape changes in the head and body. We estimated the sensitivity of three 16-electrode and impedance measurement configurations to bleeding using both idealized spherical and realistic geometry three-dimensional finite element models of the neonatal head. Sensitivity distribution responses to alterations in skull composition as well as introduction of conductivity anomalies were determined. Of the three patterns tested, a measurement scheme that employed electrodes at locations based on the 10-20 EEG layout, and impedance measurements involving current return over the anterior fontanelle produced superior distinguishabilities in regions near the lateral ventricles. This configuration also showed strongly improved sensitivities and selectivities when skull composition was varied to include the anterior fontanelle. A pattern using electrodes placed in a ring about the equator of the model had similar sensitivities but performed worse than the EEG layout in terms of selectivity. The third pattern performed worse than either the Ring or EEG-based patterns in terms of sensitivity. The overall performance of the EEG-based pattern on a spherical homogeneous model was maintained in a sensitivity matrix calculated using a homogeneous realistic geometry model.

In vivoquantification of intraventricular hemorrhage in a neonatal piglet model using an EEG-layout based electrical impedance tomography array

“…In previous papers (Sadleir and Tang 2009, Sadleir et al 2009, Tang et al 2010, Tang and Sadleir 2010, 2011) we described promising results in numerical simulations and phantom experiments. We found that an 16-electrode layout based on the electroencephalograph (EEG) 10–20 layout, combined with a measurement strategy that involved applying a sequence of current patterns with all return paths over the anterior fontanel (the ‘Cz pattern’) was superior to other patterns considered.…”

“…The sensitivity matrix may be computed from a finite element model of the imaged domain (Sadleir and Tang 2009). We found that reliable representations of introduced anomalies were produced when the head was modeled as a homogeneous sphere (Tang and Sadleir 2011), and this model was used as the sensitivity matrix in the in vivo reconstructions presented here.…”

“…A monitoring strategy is appropriate if early detection is required, or for investigations of the etiology of IVH. The variation in clinical presentation and need to intervene early further stresses the need for a simple to interpret device that can monitor and detect IVHs in real time (Sadleir and Tang 2009). …”

“…Furthermore, unlike magnetic resonance imaging (MRI), computed tomography (CT) and even ultrasound, EIT can be used in continuous monitoring mode and thus can be used to alert clinicians of the onset of bleeding (Sadleir and Tang 2009, Bera 2015). …”

Application of Electrical Impedance Tomography for Continuous Monitoring of Retroperitoneal Bleeding After Blunt Trauma

“…EIT systems have been reported to be used as research devices to investigate lung function, brain function, heart function, breast cancer, etc. 4,5,9,11,13,18,20 The region of interest within the cross-sectional images is well defined and EIT has the potential for quantification and visualization of regional ventilation. 1,10 In the case of abdominal applications, gastric function has been studied and assessed using EIT.…”