Systems And Methods For Combined Ultrasound And Electrical Impedance Imaging

• US 20110034806A1
• Filed: 01/07/2009
• Published: 02/10/2011
• Est. Priority Date: 01/09/2008
• Status: Active Grant

• Current Assignee: Dartmouth College, The Trustees of Dartmounth College (Dartmouth College)
• Original Assignee: The Trustees of Dartmounth College (Dartmouth College)
• Inventors: Paulsen, Keith D., Hartov, Alex
• Granted Patent: US 8,886,291 B2
• Time in Patent Office: Days
• US Class Current: 600/443
• CPC Class Codes: A61B 5/0035 adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
• CPC Class Codes: A61B 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: A61B 5/7425 Displaying combinations of multiple images regardless of image source, e.g. displaying a reference anatomical image with a live image geometric transforms for image registration G06T3/14; enhancement using image fusion G06T5/50; algorithms for registration of images G06T7/30
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4411 Device being modular
• CPC Class Codes: A61B 8/4416 related to combined acquisition of different diagnostic modalities, e.g. combination of ultrasound and X-ray acquisitions
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/4472 Wireless probes
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data

Abstract

A dual imaging probe 300 for obtaining both ultrasound and electrical impedance data is disclosed along with methods of using the dual imaging probe 300 to interrogate tissue. An electrical impedance imaging overlay 330 is adapted to be positioned on a transducer window 304 of an ultrasound probe 320, and may be integrally formed as part of the ultrasound probe 320 or as a modular adapter for coupling with, and optionally uncoupling from, an ultrasound probe 320 to form the dual imaging probe 300. A method (FIG. 6) of reconstructing composite images using both ultrasound and electrical impedance data is described. Applications for medical diagnosis are described. A particular use for prostate imaging is described.

Claims

1. An electrical impedance imaging (EII) overlay 330 adapted to be positioned on an ultrasound probe, the EII overlay being substantially transparent to ultrasound and comprising a plurality of electrodes 314 for electrically contacting tissue, the overlay configured such that when attached to an ultrasound probe 320 at least some of the electrodes of the overlay locate over an ultrasound transducer window 304 of the probe.

2. The EII overlay of claim 1, wherein the EII overlay 330 is formed as a modular adapter for coupling with the ultrasound probe 320.

3. The EII overlay of claim 1, wherein the EII overlay 330 comprises a flexible printed circuit.

4. The EII overlay of claim 1, wherein the EII overlay 330 provides an electrical current of less than 10 mA.

5. A dual-mode imaging probe 300, comprising:

an ultrasound probe 320; and

an electrical impedance imaging (EII) electrode 314 array having at least one electrode for electrically contacting tissue, the at least one electrode located to provide an EII currents through a portion of tissue that overlaps an area in tissue within an ultrasound field of view of an ultrasound window 304 of the dual imaging probe 300.

6. The dual imaging probe 300 of claim 5, wherein the EII electrode array 314 is integrally formed with the ultrasound probe 320.

7. The dual imaging probe of claim 5, wherein the EII electrode array 314 is formed as an EII overlay 330 and is formed as a modular adapter for coupling with the ultrasound probe 320.

8. The dual imaging probe 300 of claim 5, wherein the ultrasound probe 320 produces a frequency between 6 MHz and 30 MHz.

9. The dual imaging probe 300 of claim 8, wherein the ultrasound probe 320 produces a frequency between 6 MHz and 15 MHz.

10. The dual imaging probe 300 of claim 5, wherein the EII electrode array 314 provides an electrical current of less than 10 mA.

11. A method for imaging tissue using a dual imaging probe 300, comprising:

transmitting 404 acoustic signals from an ultrasound transducer into a tissue;

receiving 406 reflected acoustic signals;

transducing 408 the reflected acoustic signals into transduced electrical signals;

sending 410 the transduced electrical signals as ultrasound data to an electronic system;

transmitting 412 electrical current through a first subset of the electrodes of an electrical impedance imaging (EII) overlay into a tissue, the EII overlay comprising a plurality of electrodes;

measuring 414 parameters selected from the group consisting of electrical current and electrical voltage at each electrode of a second subset of the electrodes of the EII overlay;

sending the measured electrical parameters as EII data to the electronic system; and

analyzing 418 and co-registering the ultrasound data and the EII data to create at least one tomographic image of the tissue.

12. The method of claim 11, further comprising displaying 420 the one or more tomographic images on an output device.

13. The method of claim 11, further comprising evaluating the one or more tomographic images to make a diagnosis of damage or disease to the tissue.

14. The method of claim 11, wherein the acoustic signals have a frequency between 6 MHz and 30 MHz.

15. The method of claim 14, wherein the acoustic signals have a frequency between 6 MHz and 15 MHz.

16. The method of claim 14, wherein the electrical current is of less than 10 mA.

17. The method of claim 16, wherein the one or more tomographic images are three-dimensional.

18. The method of claim 11, wherein the tomographic images are constructed by:

extracting 502 regions from the ultrasound data;

constructing 504 a finite element model of the tissue, the finite element model having impedance parameters at each node of the model;

constraining 506 the model with the regions extracted from the ultrasound data; and

determining 508 impedance at nodes of the model such that simulation of the model approximately matches measured EII data.

19. The method of claim 18, wherein a false-color image is constructed having edges extracted from the ultrasound data and colors representing impedance at nodes of the model corresponding to the regions extracted from the ultrasound data.

20. The method of claim 11, wherein at least one electrode 314 of the EII overlay is located over an ultrasound imaging window of the probe.

21. A method for imaging tissue using a dual imaging probe, comprising:

transmitting 404 acoustic signals from a transducer of the probe;

receiving 406 reflected acoustic signals;

transducing 408 the reflected acoustic signals into transduced electrical signals;

sending 410 the transduced electrical signals as ultrasound data to an electronic system;

transmitting 412 electrical current through a first subset of a group of electrical impedance imaging (EII) electrodes of the probe;

measuring 414 parameters selected from the group consisting of electrical current and electrical voltage at each electrode of a second subset of the EII electrodes;

sending the measured electrical parameters as EII data to the electronic system; and

analyzing 418 and co-registering the ultrasound data and the EII data to create at least one EII image of the tissue wherein the EII image is constructed by;

extracting 502 regions from the ultrasound data;

constructing 504 a finite element model of the tissue, the finite element model having an impedance parameter at each node of the model;

constraining 506 the model of the tissue with the regions extracted from the ultrasound data; and

determining 508 impedance at nodes of the model of the tissue such that simulation of the model of the tissue approximately matches measured EII data.

22. The method of claim 21 wherein the tissue comprises a prostate gland.

23. A computer program product for constructing images of tissue comprising a machine readable memory device having stored therein computer readable instructions for:

reading ultrasound data, the ultrasound data acquired by transmitting acoustic signals from a transducer into tissue, receiving reflected acoustic signals, transducing the reflected acoustic signals into transduced electrical signals, and recording the transduced electrical signals as ultrasound data in an electronic system;

reading electrical impedance imaging (EII) data, the EII data having been generated by transmitting electrical current through at least a first subset of electrodes, measuring parameters selected from the group consisting of electrical current and electrical voltage at each electrode of at least a second subset of electrodes of an EII overlay, and recording the measured electrical current and voltage as EII data; and

analyzing and co-registering the ultrasound data and the EII data to create at least one composite tomographic image of the tissue.