Research on Hihg-Performance Electrical Impedance Tomography

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Electrical impedance tomography (EIT) is capable of visualizing the electrical impedance distribution and its changes related to the anatomical disorders or physiological activities in the living body, to be applied for monitoring the biological conditions such as blood-flow changes in the brain, swellings and urinary bladder content etc.In this research we developed neural network methods to solve the inverse problems in estimating the conductivity distribution from the superficial potential distribution measured via a set of electrodes densely placed on the body surface. For improving the resolution of the conductivity profile, MR-based deconvolution will be effective used when we want to identify the localized blood-flow increment in the brain ; in this case ill-posedness of the inverse problem can be well improved by applying the dynamic regularization technique. We also developed a GA method to select the best indices for MR segmentation, which is a key-technology for incorporating the MR data to the deconvolution network after segmenting the CSF,the gray-matter and the white-matter of the brain automatically.Another topic, we investigated is the use of magnetically controlled tetrapolar method to monitor the pulsatile impedance changes in the brain : we experimentally tested the system to prove the effectiveness of the method in estimating the blood-glow increment during the mental-loading tests.We are now planning to improve the resolution of magnetically controlled tetrapolar method by deconvolving the series of data obtained in the measurement with the magnetic field continuously shifted.