Pulmonary Ventilation and Pulsatile Perfusion Imaging on Premature Neonates using Simultaneous Multi-Source EIT.

We applied our Simultaneous Multi-Source Electrical Impedance Tomography (SMS-EIT) system to detect pulmonary ventilation and pulsatile perfusion on 5 preterm newborns with respiratory distress syndrome under the nasal continuous positive airway pressure (CPAP) treatment. The results show that derived impedance changes have a potential for clinical application to evaluate effects in spontaneously breathing preterm infants with and without CPAP.

Efficient Simultaneous Reconstruction of Time-Varying Images and Electrode Contact Impedances in Electrical Impedance Tomography.

Objective: In electrical impedance tomography (EIT), we apply patterns of currents on a set of electrodes at the external boundary of an object, measure the resulting potentials at the electrodes, and, given the aggregate dataset, reconstruct the complex conductivity and permittivity within the object. It is possible to maximize sensitivity to internal conductivity changes by simultaneously applying currents and measuring potentials on all electrodes but this approach also maximizes sensitivity to changes in impedance at the interface.

Methods: We have, therefore, developed algorithms to assess contact impedance changes at the interface as well as to efficiently and simultaneously reconstruct internal conductivity/permittivity changes within the body.

Detection of small bleeds in the brain with electrical impedance tomography.

In this paper, we describe and assess feasibility of instrumentation and algorithms for detecting bleeding due to hemorrhagic strokes and traumatic brain injury using electrical impedance tomography, a novel biomedical diagnostic modality in which the body is probed noninvasively with generally imperceptible alternating currents applied in patterns to a set of electrodes placed in contact with the skin. We focus on the GENESIS instrument developed by GE Global Research and on the achievability of our goal to detect a bleed in the center of the head with a volume of several ml. Our main topic is compensation for the large changes in voltages that tend to occur when the electrodes are in contact with biological media, specifically either human subjects or with vegetable matter proxies which seem to exhibit the same 'drift' phenomenon.

Comparison of impedance measurements near the skin of newborns and adults.

Electrical impedance tomography (EIT) is a non-invasive imaging technology that has been extensively studied for monitoring lung function of neonatal and adult subjects, especially in neonatal intensive care unit (NICU) and intensive care unit (ICU) environments. The sources of the total impedance in these applications include internal organs, near-boundary tissues, electrode-skin impedance, electrodes and conducting wires. This total impedance must be considered for system design and setting voltage gain since it will contribute to the measured voltage.

Peripheral nerve stimulation characteristics of an asymmetric head-only gradient coil compatible with a high-channel-count receiver array.

Purpose: To characterize peripheral nerve stimulation (PNS) of an asymmetric head-only gradient coil that is compatible with a commercial high-channel-count receive-only array.

Methods: Two prototypes of an asymmetric head-only gradient coil set with a 42-cm inner diameter were constructed for brain imaging at 3T with maximum performance specifications of up to 85 mT/m and 708 T/m/s. Tests were performed in 24 volunteers to measure PNS thresholds with the transverse (x = left-right; y = anterior-posterior [A/P]) gradient coils of both prototypes.

Real-time 3D electrical impedance imaging for ventilation monitoring of the lung: Pilot study.

We report an Electrical Impedance Tomography device capable of detecting gravity-induced regional ventilation changes in real-time without averaging or using a contrast medium. Changes in lung ventilation are demonstrated in right and left lateral decubitus position and compared to those seen in an upright and supine normal subject.

Real-time 3D electrical impedance imaging for ventilation and perfusion of the lung in lateral decubitus position.

We report a prototype Electrical Impedance Imaging System. It is able to detect the gravity-induced changes in the distributions of perfusion and ventilation in the lung between supine and lateral decubitus positions. Impedance data were collected on healthy volunteer subjects and 3D reconstructed images were produced in real-time, 20 frames per second on site, without using averaging or a contrast agent.