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Because of the intrinsically low sensitivity of any surface potential measurement to resistivity changes within a volume conductor, any data collection system for impedance imaging must be sensitive to changes in the peripheral potential profile of the order of 0.1%. For example, whilst the resistivity changes associated with lung ventilation and the(More)
  • B H Brown
  • 2003
Electrical impedance tomography (EIT) has been the subject of quite intensive research for about 20 years but has yet to become established as a routine tool in healthcare. None the less the volume of published research work in this area is still rising. This review takes a broad look at what has been achieved and attempts to give the reader sufficient(More)
The electrical resistivity of mammalian tissues varies widely and is correlated with physiological function. Electrical impedance tomography (EIT) can be used to probe such variations in vivo, and offers a non-invasive means of imaging the internal conductivity distribution of the human body. But the computational complexity of EIT has severe practical(More)
Electrical impedance tomography (EIT) is an attractive method for clinically monitoring patients during mechanical ventilation, because it can provide a non-invasive continuous image of pulmonary impedance which indicates the distribution of ventilation. However, most clinical and physiological research in lung EIT is done using older and proprietary(More)
Electrical impedance tomographic spectroscopy measurements of the lungs are taken from nine normal subjects, in the frequency range 9.6 kHz–1.2 MHz. The results show that resistivity ρ′FRC relative to functional residual capacity increases almost linearly with inspiration volume V, with the slope of the curve increasing with frequency f. Resistivity ρ′9.6(More)
Electrical recordings have been made from cutaneous electrodes placed on the trunk with a view to establishing the source of the slow potential changes which can be recorded. Cutaneous recordings have been made on 16 normal subjects in both the fasted and fed states, and in some cases simultaneous recordings have been made from electrodes attached to the(More)
Electrical impedance tomography (EIT) is a recently developed medical imaging method which has practical advantages for imaging brain function as it is inexpensive, rapid and portable. Its principal use in validated human studies to date has been to image changes in impedance at a single excitation frequency over time, but there are potential applications(More)
An electrical impedance tomographic imaging system has been developed which can monitor changes in the resistivity of the thorax at a rate of 5 frames per second. There is a high correlation (r greater than 0.95) between changes in resistivity of the lungs and the volume of air inspired. Calibration of the system allows continuous monitoring of the level of(More)
Experiments have been carried out to investigate the information transfer available via a single vibrator on the fingertip. In a first experiment, for stimuli with durations 80 to 320 ms, discrimination of a one-octave step change in frequency at the halfway point was investigated. Results were similar for three stimulus types--sinewave, monophasic pulse(More)