Three-dimensional impedance imaging process

• US 5,351,697 A
• Filed: 09/29/1993
• Issued: 10/04/1994
• Est. Priority Date: 12/16/1991
• Status: Expired due to Term

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Isaacson, David, Cheney, Margaret
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US08/128,834
• Time in Patent Office: 370 Days
• Field of Search: 128/734, 364/413.13
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: G01R 27/26 Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

A method for obtaining sets of current patterns for three-dimensionally imaging the interior of a body having an internal resistivity using electrical impedance tomography comprises providing an array of electrodes arranged in a plurality of groups for an impedance imaging system. A linearly independent set of current patterns is also established for forming a basis for each group. A constant pattern is then adjoined to each basis for forming an augmented basis for each group. A tensor product is then taken of the augmented basis for forming a tensor product basis. Finally, the constant pattern from the tensor product basis is removed in order to establish a basis of current patterns for being applied to the array of electrodes.

Claims

1. A method for electrical impedance imaging by obtaining and using sets of current patterns for three-dimensionally imaging the interior of a body having an internal resistivity using electrical impedance tomography, the method comprising:

providing a multidimensional array of electrodes arranged in a plurality of groups for an impedance imaging system;

establishing a linearly independent set of current patterns for forming a basis for each group;

adjoining a constant pattern to each basis for forming an augmented basis for each group;

taking the tensor product of the augmented bases for forming a tensor product basis for each group;

removing the constant pattern from the tensor product basis for establishing a basis of current patterns for being applied to the array of electrodes;

applying the current patterns to the electrodes to form voltage patterns at the electrodes; and

measuring the voltage patterns to create an electrical impedance image of the body.

2. The method according to claim 1, including selecting the current patterns to be trigonometric patterns.

3. The method according to claim 1, including selecting the current patterns to be Walsh patterns.

4. A method according to claim 1, including selecting the array to be a matrix of electrodes, some of the plurality of groups comprising rows of electrodes in the matrix and others of the plurality of groups comprising columns of electrodes in the matrix.