CompanyName: Middle East Technical Univ.

Country: Turkey


B. Murat EYÜBOGLU* and Y.Ziya IDER**
*Dept. of Electrical and Electronics Engineering, Middle East Technical University,
**Dept. of Electrical and Electronics Engineering, Bilkent University,
Ankara - TURKEY

Magnetic Resonance - Electrical Impedance Tomography (MR-EIT)
is an imaging modality, which is developed to produce images
of true conductivity with high resolution. Electric current
applied to a conductor body, results in a potential field and
a magnetic flux density distribution inside the body. Conventional
EIT uses the voltage measurements made on the surface of the
conductor to reconstruct images of conductivity distribution
inside. Sensitivity of peripheral voltage measurements to internal
conductivity perturbations and spatial resolution of the reconstructed
images are position dependent. In fact, sensitivity and spatial
resolution degrade with the distance from the surface. The best
spatial resolution is in the order of a few centimeters, for an
average human thorax. Magnetic flux density distribution can be
imaged using Magnetic Resonance Imaging (MRI) techniques. Relative
distribution of conductivity can be related to the flux density
distribution and conductivity images can be reconstructed utilizing
flux density measurements. Sensitivity of measurements to internal
conductivity perturbations is uniform in this case, since the measurements
are made for the entire object. Spatial resolution is also independent
of position and in the order of a few millimeters. Combining magnetic flux
density measurements with EIT surface potential measurements, images
of true conductivity distribution can be obtained. We present several
MR-EIT reconstruction algorithms developed by our group in Ankara, the
results of performance tests on simulated data and the results of experiments
performed on 0.15 Tesla METU-MRI system.

Close Window