Biomedical subjects
Publications and source records attributed to M Granié.
This paper represents a reconstruction algorithm using a direct sensitivity matrix (DSM) approach for fast 3D image reconstruction in electrical impedance imaging. The boundary element method (BEM) is used in the construction of this matrix. The first images of a conductivity perturbation inside a sphere are reconstructed, using theoretical data.
Two experimental set-ups for in vitro characterization of electrical bio-impedance are described. The first one, based on a commercially available instrument, operates in the frequency range 1 Hz-10 MHz. The second one uses an identification process and operates in the frequency range 1 Hz-1 MHz. Some results are presented and discussed in the context of multifrequency electrical impedance tomography.
In electrical impedance imaging, several proposed reconstruction algorithms have employed the concept of a sensitivity matrix, which can be used to relate the magnitude of a boundary voltage change of a 2D object to the change in conductivity inside the object that has given rise to it. The search for an appropriate inversion of the sensitivity matrix is the key to these algorithms. In this work, a method called the direct sensitivity matrix (DSM) approach for fast image reconstruction is proposed. Both theoretical and experimental results showing the efficiency of this proposed method are also presented.
Optimal control techniques have been combined with Alessandrini's singular perturbation method and Wexler's algorithm to reconstruct images in impedance imaging. We have also considered an integral formulation of the potential problem, which has led us to introduce an array of dipoles whose position, orientation and length can be optimised to model the conductivity discontinuities.
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Is there an effect on binocular coordination during reading of oculomotor imbalance (heterophoria, strabismus and inadequate convergence) and of functional lateral characteristics (eye preference and perceptually privileged visual laterality)? Recordings of the binocular eye-movements of ten-year-old children show that oculomotor imbalances occur most often among children whose left visual perceptual channel is privileged, and that these subjects can present optomotor dissociation and manifest lack of motor coordination. Close binocular motor coordination is far from being the norm in reading. The faster reader displays saccades of differing spatial amplitude and the slower reader an oculomotor hyperactivity, especially during fixations. The recording of binocular movements in reading appears to be an excellent means of diagnosing difficulties related to visual laterality and to problems associated with oculomotor imbalance.