Ultrasonic Characterization of Internal Body Conditions Using Information Theoretic Signal Receivers

Abstract

Disclosed herein is a technique for performing medical imaging on a region of interest (ROI) wherein information theoretic signal receivers are used to enhance the detection and monitoring of pathologies such as angiogenesis and muscular dystrophy. Examples of information theoretic signal receivers that can be used in the practice of the invention include Shannon entropy signal receivers, continuous limit Shannon entropy signal receivers, Renyi entropy signal receivers, specific heat analog signal receivers, and thermodynamic energy analog signal receivers. The contrast enhancement provided by contrast agents, either targeted contrast agents or bubble-based contrast agents, is enhanced through the use of such information theoretic signal receivers. Further still, the contrast agents can be heated to further enhance visualization with information theoretic signal receivers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary overview of an imaging system capable of implementing the present invention;

FIG. 2 depicts an exemplary flowchart that describes a methodology of a preferred embodiment of the present invention;

FIG. 3 depicts an exemplary perfluorocarbon nanoparticle emulsion;

FIG. 4 depicts an exemplary cumulative distribution function histogram with upper 5% thresholding;

FIG. 5 depicts an exemplary flowchart that describes a methodology for a microbubble-based contrast agent imaging embodiment;

FIG. 6 depicts an exemplary flowchart that describes a methodology for an embodiment wherein heating is used to enhance performance;

FIG. 7 depicts a plot of contrast enhancement as a function of temperature for an information theoretic signal receiver and conventional signal receivers;

FIG. 8 illustrates “contact-facilitated” drug delivery that can be monitored through the use of the present invention; and

FIG. 9 illustrates images produced in accordance with the present invention showing contrast enhancement of targeted areas corresponding to a VX-2 tumor in a New Zealand white rabbit.

Claims

1. A method for imaging a region of interest (ROI) within a body to obtain an image indicative of a condition of muscular dystrophy affecting the ROI, the method comprising: applying ultrasound energy to the ROI;acquiring raw ultrasound data for the ROI in response to the applied energy; andapplying an information theoretic signal receiver to the acquired raw ultrasound data to thereby generate information theoretic data from which an ultrasound image of the ROI can be created, wherein the ultrasound image is indicative of a condition of muscular dystrophy affecting the ROI.

2. The method of claim 2 wherein the ROI comprises tissue that has been treated with a steroid.

3. The method of claim 2 further comprising repeating the method steps over time to determine a progressive condition of the muscular dystrophy affecting the steroid-treated tissue over time.

4. The method of claim 3 wherein the repeating step is performed without requiring exact matching of previous settings for an ultrasound imager when it performs the applying and raw ultrasound data acquiring steps.

5. The method of claim 3 wherein the ROI comprises tissue that has been treated with a steroid, the method further comprising: applying an energy-based signal receiver to the acquired raw ultrasound data to thereby generate data from which another ultrasound image of the ROI can be created; anddetermining the progressive condition of the muscular dystrophy affecting the steroid-treated tissue based on a combination of the information theoretic-based ultrasound image and the energy-based ultrasound image.

6. The method of claim 1 wherein the applying step comprises applying ultrasound energy to the ROI wherein the applied ultrasound energy has a frequency in a range of approximately 2 MHz to approximately 15 MHz.

7. A method for imaging a region of interest (ROI) within a volume to obtain an image indicative of whether a condition of interest exists within the volume, the method comprising: injecting the region of interest with a contrast agent that is targeted to the condition of interest;applying ultrasound energy to the ROI;acquiring ultrasound data for the ROI in response to the applied energy; andapplying an information theoretic signal receiver to the acquired ultrasound data to thereby generate information theoretic data from which an ultrasound image of the ROI can be created, wherein the ultrasound image is indicative of whether the condition of interest exists within the volume.

8. The method of claim 7 wherein the step of applying ultrasound energy comprises applying ultrasound energy to the ROI wherein the applied ultrasound energy has a frequency in a range of approximately 2 MHz to approximately 15 MHz.

9. The method of claim 8 wherein the condition of interest comprises angiogenesis.

10. The method of claim 8 further comprising repeating the ultrasound energy applying step, the acquiring step and the information theoretic signal receiver applying step over time to monitor how the condition of interest progresses over time.

11. The method of claim 10 wherein the contrast agent comprises a targeted contrast agent that has been loaded with a therapeutic drug for contact-facilitated drug delivery, and wherein the repeating step thereby allows the drug delivery to be monitored over time.

12. The method of claim 8 wherein the contrast agent comprises a bubble-based contrast agent.

13. The method of claim 8 wherein the condition of interest comprises tissue affected by muscular dystrophy.

14. The method of claim 7 wherein the acquiring step comprises: (1) receiving raw ultrasound data in response to the applied ultrasound energy and upsampling the raw ultrasound data to stabilize the information theoretic signal receiver when it is applied to the acquired ultrasound data, and (2) performing a moving window analysis on the upsampled data to generate a plurality of windows of upsampled data, and wherein the information theoretic signal receiver applying step comprises applying an information theoretic signal receiver to each generated window of upsampled data.

15. The method of claim 7 wherein the step of applying an information theoretic signal receiver comprises applying at least one member selected from the group consisting of: a Shannon entropy (Hs) signal receiver, a continuous limit Shannon entropy (Hc) signal receiver, a Renyi entropy (Z) signal receiver, a specific heat analog (Cv) signal receiver, and a thermodynamic energy analog (Eth) signal receiver to the acquired ultrasound data to thereby generate an ultrasound image that is indicative of whether the condition of interest exists within the volume.

16. The method of claim 7 wherein the ROI comprises a region within a patient's body having a plurality of cells, the method further comprising heating at least a portion of the ROI to a temperature that is nonlethal to a majority of cells within the ROI after the contrast agent has been injected and prior to the ultrasound data acquiring step.

17. The method of claim 16 wherein the heating step comprises applying the heat to the ROI with a heating pulse of ultrasound energy.

18. The method of claim 7 wherein the information theoretic data comprises a plurality of pixels having data values, the method further comprising: defining a threshold for the information-theoretic data;selecting pixels of the information theoretic data whose data values are equal to or greater than the threshold; andgenerating the ultrasound image by combining the acquired ultrasound data with the selected pixels to create a hybrid ultrasound image.

19. A method for imaging a region of interest (ROI) within a volume to obtain an image indicative of whether a condition of interest exists within the volume, the method comprising: injecting the ROI with a contrast agent, the contrast agent comprising a plurality of bubbles;applying a first ultrasound energy to an area within the ROI, wherein the ultrasound energy has sufficient power to eliminate substantially all of the bubbles from the area;after the area has refilled with a plurality of wash-in bubbles, applying a second ultrasound energy to the area within the ROI, wherein the ultrasound energy has a sufficiently low power to not eliminate the wash-in bubbles;acquiring raw ultrasound data for the ROI in response to the applied second ultrasound energy;applying an information theoretic signal receiver to the acquired raw ultrasound data to thereby generate an ultrasound image that is indicative of whether the condition of interest exists within the volume.

20. The method of claim 19 wherein the contrast agent comprises at least one selected from the group consisting of a microbubble-based contrast agent and a nanobubble-based contrast agent, and wherein the step of applying the second ultrasound energy comprises applying second ultrasound energy to the ROI at a clinical frequency.