Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Local control of temperature in a theoretical human model of selective brain cooling.
A method of feedback control of local brain temperature during therapeutic intracarotid cold saline infusion is presented and tested on a theoretical cerebral heat transfer model based on the Pennes bioheat equation. In this temperature control method, the infusion rate of cold saline is varied based on the rate of temperature change, and the deviation of temperature to a target, within a voxel in the treated region of brain. ⋯ Two hours of treatment decreased the required inflow of ice-cold saline from 30 ml/min to 21 and 7 ml/min in the non-ice and ice cases, respectively. Intracarotid hematocrit had higher values in the non-ice case.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
The complete electrode model for imaging and electrode contact compensation in electrical impedance tomography.
Electrical Impedance Tomography (EIT) is an imaging modality which currently shows promise for the detection and characterization of breast cancer. A very significant problem in EIT imaging is the proper modeling of the interface between the body and the electrodes. We have found empirically that it is very difficult, in a clinical setting, to assure that all electrodes make satisfactory contact with the body. ⋯ To compensate for these problems, we have developed a hybrid nonlinear-linear reconstruction algorithm in which we first estimate electrode surface impedances, using a Newton-type iterative optimization procedure with an analytically computed Jacobian matrix. We subsequently make use of a linearized algorithm to perform a three-dimensional reconstruction of perturbations in both contact impedances and in the spatial distributions of conductivity and permittivity. Results show that, using this procedure, artifacts due to electrodes making poor contact can be greatly reduced.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
A simple and efficient algorithm with a coarse to fine approach for arterial beat pulse detection.
This paper presents a simple algorithm for arterial beat pulse detection. It consists in a coarse to fine approach : the first step is performed with a lifting Haar wavelet transform with thresholding and provides search intervals, the second step is to localize the beat pulse in the original signal within these areas. Thanks to online available database, the performance of this algorithm can be compared to others and its ability to detect peaks is sufficient considering its low amount of calculation.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Clinical TrialA system for analyzing intraoperative B-Mode ultrasound scans of the liver.
In this article, a system for automatic analysis of intraoperative B-Mode ultrasound images of the liver is presented. The system is part of an assistance system for open liver surgery. ⋯ With this segmentation results, an ultrasound based 3D-model of the vascular structure is extracted and manually registered to a preoperative CT-based model. Anatomical landmarks like bifurcations of vessels are automatically extracted in the ultrasound-based model and will be used for an automatic registration process in further developments.
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the continuous monitoring of splanchnic organ oxygen saturation (SpO2) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischemia, multiple organ failure, and, ultimately, death. In an attempt to create a splanchnic SpO2 sensor that can be used intra-operatively, pre-operatively and post-operatively this paper describes the design and technical evaluation of fiber optic based reflectance pulse oximeter sensor and processing system. In a detailed investigation to determine the optimal source-emitter spacing it was found that the optimum separation distance was between 3mm and 6mm. In vivo thermal testing showed that the rise in temperature at the tip of the fiber at both wavelengths was insignificant and therefore should have no effect in the splanchnic tissue.