Towards continuous EIT monitoring for hemorrhagic stroke patients.

The practical implementation of continuous monitoring of stroke patients by Electrical Impedance Tomography (EIT) is addressed. In a previous paper, we have demonstrated EIT sensitivity to cerebral hemodynamics, using scalp-mounted electrodes, very low-noise measurements, and a novel image reconstruction method. In the present paper, we investigate the potential to adapt that system for clinical application, by using 50% fewer electrodes and by incorporating into the measurement protocol an additional high-frequency measurement to provide an effective reference.

Scalp-Mounted Electrical Impedance Tomography of Cerebral Hemodynamics.

An Electrical Impedance Tomography (EIT) system has been developed for dynamic three-dimensional imaging of changes in conductivity distribution in the human head, using scalp-mounted electrodes. We attribute these images to changes in cerebral perfusion. At 100 frames per second (fps), voltage measurement is achieved with full-scale signal-to-noise ratio of 105 dB and common-mode rejection ratio > 90 dB.

CSTNet: A Dual-Branch Convolutional Neural Network for Imaging of Reactive Flows Using Chemical Species Tomography.

Chemical species tomography (CST) has been widely used for in situ imaging of critical parameters, e.g., species concentration and temperature, in reactive flows.

Reconstruction of two-dimensional velocity distribution in scramjet by laser absorption spectroscopy tomography.

We propose a method to reconstruct the two-dimensional (2D) velocity distribution of flow fields by laser absorption spectroscopy tomography. A mathematic model is established to reveal the dependence of spectral absorbance on line-of-sight velocity distribution. Then, with multiple laser beams from different angular views covering the region of interest, a nonlinear equation set of 2D velocity distribution is established according to the model.

Constrained models for optical absorption tomography.

We consider the inverse problem of concentration imaging in optical absorption tomography with limited data sets. The measurement setup involves simultaneous acquisition of near-infrared wavelength-modulated spectroscopic measurements from a small number of pencil beams equally distributed among six projection angles surrounding the plume. We develop an approach for image reconstruction that involves constraining the value of the image to the conventional concentration bounds and a projection into low-dimensional subspaces to reduce the degrees of freedom in the inverse problem.

Tackling modelling error in the application of electrical impedance tomography to the head.

In the head application of Electrical Impedance Tomography (EIT), reconstruction of voltage measurements for a conductivity distribution image using an ordinary method, the absolute imaging approach, is impossible due to the traditional ignorance of modelling error. The modelling error comes from the inaccuracy of geometry and structure, which are unable to be known accurately in practice, and are usually large in head application of EIT. Difference imaging is an alternative approach which is able to reduce the size of this error, but it introduces other kinds of error.

The Brady Bunch? New evidence for nominative determinism in patients' health: retrospective, population based cohort study.

Objective: To ascertain whether a name can influence a person's health, by assessing whether people with the surname "Brady" have an increased prevalence of bradycardia.

Design: Retrospective, population based cohort study.

Setting: One university teaching hospital in Dublin, Ireland.

Multiwavelength diode-laser absorption spectroscopy using external intensity modulation by semiconductor optical amplifiers.

A novel opto-electronic scheme for line-of-sight Near-IR gas absorption measurement based on direct absorption spectroscopy (DAS) is reported. A diode-laser-based, multiwavelength system is designed for future application in nonintrusive, high temporal resolution tomographic imaging of H2O in internal combustion engines. DAS is implemented with semiconductor optical amplifiers (SOAs) to enable wavelength multiplexing and to induce external intensity modulation for phase-sensitive detection.

A portable instrument for high-speed brain function imaging: FEITER.

Electrical Impedance Tomography (EIT) can resolve dynamic physiological information deep within human subjects [1], but its sensitivity is challenged in the case of imaging the head [2]. Here, we report a new system called fEITER that has been designed and built to enable functional imaging of the human brain using EIT via scalp-mounted electrodes, integrated with stimulation of evoked responses. Using Field-Programmable Gate Array (FPGA) technology, it provides excellent flexibility in terms of current-pattern excitation and signal processing.

The Dublin cardiac arrest registry: temporal improvement in survival from out-of-hospital cardiac arrest reflects improved pre-hospital emergency care.

Aims: Out-of-hospital cardiac arrest (OOHCA) survival remains poor, estimated at 3-7%. We aim to describe the incidence of OOHCA, survival from OOHCA, and the impact of improved pre-hospital care on survival from OOHCA.

Methods And Results: A retrospective registry was established using multi-source information to assess survival from cardiac arrest following the introduction of several improvements in pre-hospital emergency medical care from 2003.

Contemporary management of and outcomes from cardiac device related infections.

Aims: To describe the incidence and management of cardiac device infection. Infection is a serious, potentially fatal complication of device implantation. The numbers of device implants and infections are rising.

Dobutamine stress echo-induced apical ballooning (Takotsubo) syndrome.

Aims: We report a case of dobutamine stress echocardiography (DSE) resulting in transient apical ballooning syndrome to highlight this rare condition as a potential complication of DSE.

Background: Takotsubo cardiomyopathy, or transient apical ballooning syndrome, is a recently described form of left ventricular (LV) dysfunction induced by stress. Clinically it can mimic acute coronary syndrome in its presentation.

Toward in-cylinder absorption tomography in a production engine.

Design requirements for an 8000 frame/s dual-wavelength ratiometric chemical species tomography system, intended for hydrocarbon vapor imaging in one cylinder of a standard automobile engine, are examined. The design process is guided by spectroscopic measurements on iso-octane and by comprehensive results from laboratory phantoms and research engines, including results on temporal resolution performance. Novel image reconstruction techniques, necessary for this application, are presented.

Krylov subspace iterative techniques: on the detection of brain activity with electrical impedance tomography.

In this paper, we review some numerical techniques based on the linear Krylov subspace iteration that can be used for the efficient calculation of the forward and the inverse electrical impedance tomography problems. Exploring their computational advantages in solving large-scale systems of equations, we specifically address their implementation in reconstructing localized impedance changes occurring within the human brain. If the conductivity of the head tissues is assumed to be real, the pre-conditioned conjugate gradients (PCGs) algorithm can be used to calculate efficiently the approximate forward solution to a given error tolerance.