Tissue liquid detection system

Patent metadata

Field	Value
Publication number	US-9907540-B2
Application number	US-201214362907-A
Country	US
Kind code	B2
Filing date	Jun 11, 2012
Priority date	Jun 11, 2012
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A method of detecting liquid in animal tissue is disclosed. The method comprises providing an electromagnetic radiation generator, and applying electromagnetic radiation to a tissue region using the electromagnetic radiation generator. The characteristics of the electromagnetic radiation are selected so as to cause differential heating in a tissue region based on liquid content in the tissue region, differential expansion of matter in the tissue region, and thereby generation of ultrasound signals that vary according to the liquid content. The method also comprises providing an ultrasound detector, detecting the ultrasound signals using the ultrasound detector, and using the detected ultrasound signals to produce an indication of concentration of liquid in the tissue region and a determination as to whether a change in liquid concentration in the tissue region has occurred.

First claim

The invention claimed is:

1. A method of detecting a liquid in an animal tissue, the method comprising:
applying electromagnetic radiation to a tissue region using an electromagnetic radiation generator, wherein characteristics of the electromagnetic radiation are selected so as to cause differential heating in the tissue region based on liquid content in the tissue region, thereby causing differential expansion of matter in the tissue region and generation of ultrasound signals that vary according to the liquid content in the tissue region;
providing an ultrasound detector;
detecting the generated ultrasound signals using the ultrasound detector;
using the detected ultrasound signals to determine a liquid content value in the tissue region based on ultrasound pulses generated in response to expansion of the tissue region, wherein the expansion of the tissue region is based on the differential heating of the liquid in the tissue region, and to determine whether a change in liquid concentration in the tissue region has occurred based on a comparison of the detected ultrasound signals with reference ultrasound signals; and
determining whether the liquid content value is abnormal based on a comparison of the liquid content value to stored values of expected liquid content.

2. The method as claimed in claim 1 , wherein the electromagnetic radiation generator comprises a microwave, near infra-red, or RF signal generator.

3. The method as claimed in claim 1 , wherein the electromagnetic radiation generator comprises an electromagnetic pulse generator arranged to generate electromagnetic pulses, wherein the electromagnetic pulses comprise microwave pulses.

4. The method as claimed in claim 3 , wherein applying the electromagnetic radiation comprises applying the microwave pulses of duration substantially in the range 0.5 μs to 2 μs.

5. The method as claimed in claim 4 , wherein applying the microwave pulses comprises applying the microwave pulses of average power substantially in the range 0.75 W to 60 W.

6. The method as claimed in claim 5 , wherein applying the microwave pulses comprises applying the microwave pulses of frequency substantially in the range 50 Hz to 4 kHz.

7. The method as claimed in claim 1 , wherein using the detected ultrasound signals comprises using the detected ultrasound signals to produce an absorption profile indicative of absorption of electromagnetic energy in the tissue region, and comparing the absorption profile with a previously generated reference absorption profile and using the comparison to determine whether the absorption profile is indicative of the change in liquid concentration in the tissue region.

8. The method as claimed in claim 1 , wherein using the detected ultrasound signals comprises using the detected ultrasound signals to produce the liquid content value indicative of an average detected ultrasound intensity, and comparing the liquid content value with a reference recovery profile for a patient, and wherein the reference recovery profile defines the expected change in the liquid content value over time.

9. The method as claimed in claim 8 , further comprises selecting the reference recovery profile using biometric data associated with the animal tissue, wherein the biometric data includes at least one of temperature, body weight, age, and location of the tissue region.

10. The method as claimed in claim 1 , further comprising disposing liquid absorptive material adjacent to the tissue region and determining whether the absorption profile is indicative of the change in the liquid concentration in the tissue region based on a detected liquid content value in the liquid absorptive material.

11. A method of detecting an anastomotic leakage in a patient, the method comprising:
applying electromagnetic radiation to an anastomosis tissue region using an electromagnetic radiation generator, wherein characteristics of the electromagnetic radiation are selected so as to cause differential heating in the tissue region based on liquid content in the tissue region, thereby causing expansion of matter in the tissue region and generation of ultrasound signals that vary according to the liquid content in the tissue region;
providing an ultrasound detector;
detecting the generated ultrasound signals using the ultrasound detector;
using the detected ultrasound signals to determine a liquid content value in the tissue region based on ultrasound pulses generated in response to expansion of the tissue region, wherein the expansion of the tissue region is based on the differential heating of the liquid in the tissue region, and to determine whether a leakage of the liquid from the anastomosis tissue region has occurred based on a comparison of the detected ultrasound signals with reference ultrasound signals; and
determining whether the liquid content value is abnormal based on a comparison of the liquid content value to stored values of expected liquid content.

12. The method as claimed in claim 11 , wherein the anastomosis tissue is colorectal anastomosis tissue.

13. A system for detecting a liquid in an animal tissue, the system comprising:
an electromagnetic radiation generator arranged to apply electromagnetic radiation to a tissue region, wherein characteristics of the electromagnetic radiation selected so as to cause differential heating in a tissue region based on liquid content in the tissue region, thereby causing expansion of matter in the tissue region and generation of ultrasound signals that vary according to the liquid content in the tissue region;
an ultrasound detector arranged to detect the ultrasound signals;
the system further comprising an analyzer arranged to:
use the detected ultrasound signals to determine a liquid content value in the tissue region based on ultrasound pulses generated in response to expansion of the tissue region, wherein the expansion of the tissue region is based on the differential heating of the liquid in the tissue region;
determine whether a leakage of the liquid from the anastomosis tissue region has occurred based on a comparison of the detected ultrasound signals with reference ultrasound signals; and
determine whether the liquid content value is abnormal based on a comparison of the liquid content value to stored values of expected liquid content.

14. The system as claimed in claim 13 , wherein the electromagnetic radiation generator is arranged to generate microwave, near infra-red, or RF signals.

15. The system as claimed in claim 13 , wherein the electromagnetic radiation comprises microwave radiation.

16. The system as claimed in claim 15 , wherein the microwave radiation comprises microwave pulses of duration substantially in the range 0.5 μs to 2 μs.

17. The system as claimed in claim 16 , wherein the microwave pulses comprise an average power substantially in the range 0.75 W to 60 W.

18. The system as claimed in claim 13 , wherein the electromagnetic radiation comprises frequency of pulses substantially in the range 50 Hz to 4 kHz.

19. The system as claimed in claim 13 , wherein the analyzer is configured to use the detected ultrasound signals to produce the liquid content value indicative of an average detected ultrasound intensity and compare the liquid content value with a reference recovery profile for a patient, wherein the reference recovery profile defines the expected change in the liquid content value over time, and wherein the analyzer is configured to use biometric data associated with the patient to select the reference recovery profile,

Assignees

• Kery Robert
• Gal John
• Chen Sung Wei
• Rothfuss Christopher J
• Empire Technology Dev Llc

Inventors

• Kery Robert
• Gal John
• Chen Sung Wei

Classifications

• A61B8/48

  Diagnostic techniques (A61B8/13 takes precedence) · CPC title

• A61B8/5223 Primary

  for extracting a diagnostic or physiological parameter from medical diagnostic data (for algorithms to analyse biomedical images G06T7/0012) · CPC title

• A61B5/4848

  Monitoring or testing the effects of treatment, e.g. of medication · CPC title

• A61B8/0858

  involving measuring tissue layers, e.g. skin, interfaces · CPC title

• A61B5/0507

  using microwaves or terahertz waves · CPC title