Method and apparatus for mapping pressure and tissue properties
First Claim
1. A method of mapping and presenting a fluid pressure parameter in a living body comprising the steps of:
- introducing microbubbles into said body;
applying ultrasound waves to the body wherein returned waves from the microbubbles contribute to the formation of an acoustic spectrum associated with the microbubbles;
determining a fluid pressure parameter in response to at least one characteristic of the acoustic spectrum; and
mapping the fluid pressure parameter in at least two dimensions.
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Abstract
The invention disclosed relates to a novel method of mapping and presenting fluid pressure information within a living body utilizing changes in acoustic behavior of microbubbles situated in a bodily fluid such as blood. Differences in the returned acoustic spectra from the microbubbles are related by an algorithm to fluid pressure which is colorized and presented in a manner similar to Doppler imaging. In a further aspect of the invention, the work output of an organ such as the heart may computed from the blood pressure information in association with flow information obtained through Doppler related imaging, which then, is presented in a colorized fashion. In a still further aspect, an improved method of assessing the health of tissue is disclosed utilizing changes in the acoustic spectra of microbubbles infused in the tissue in response to palpitation.
297 Citations
54 Claims
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1. A method of mapping and presenting a fluid pressure parameter in a living body comprising the steps of:
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introducing microbubbles into said body; applying ultrasound waves to the body wherein returned waves from the microbubbles contribute to the formation of an acoustic spectrum associated with the microbubbles; determining a fluid pressure parameter in response to at least one characteristic of the acoustic spectrum; and mapping the fluid pressure parameter in at least two dimensions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of mapping and graphically presenting in at least two dimensions the hydraulic work performed by or on a bodily organ or vasculature comprising the steps of:
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introducing microbubbles into a living body such that the microbubbles enter the organ or vasculature; applying ultrasound waves to the body wherein returned waves from the microbubbles contribute to the formation of an acoustic spectrum associated with the microbubbles; and determining a pressure parameter in response to at least one characteristic of the acoustic spectrum; wherein said hydraulic work is computed from, at least in part, a product of pressure parameter and flow information obtained using Doppler-related techniques. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 32, 33)
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31. A method according to 22 wherein microbubble behavior is observed in a time period of a blood pressure cycle.
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34. A method of assessing the health of bodily organs, vasculature, or bodily tissue comprising the steps of:
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introducing microbubbles into the body; applying high frequency sound waves to the region to be examined thereby causing an acoustic spectrum to be returned from the microbubbles; determining pressure changes in response to at least one characteristic of the returned acoustic spectrum of microbubbles infused in said organs and tissue, wherein differences in the spectral characteristics of the microbubbles are used to assess the presence of abnormalities in the examined region and are displayed in at least a two dimensional mapping for presentation to the user.
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35. A method according to 34 wherein the characteristics are comprised of changes of at least one of:
- a microbubble resonant frequency;
a microbubble harmonic frequency;
reflective power;
degree of contrast; and
amplitude and phase angle.
- a microbubble resonant frequency;
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36. A method according to 34 wherein the presence of abnormalities is presented in a colorized fashion wherein the state of health is depicted as:
- areas that contain no abnormalities are represented in blue;
areas containing abnormalities are represented in red; and
areas containing varying degrees of abnormalities are represented as a gradation between red and blue in accordance to the degree.
- areas that contain no abnormalities are represented in blue;
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37. A method according to 34 wherein the mapped representation of the health of the organ, vasculature, or tissue is presented in conjunction with other ultrasound imaging modalities.
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38. A method according to 34 wherein spectral characteristic is observed in a time period during the influence of an external probing low frequency wave applied to the region being examined.
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39. A method according to 34 wherein spectral characteristic is observed in a time period after the influence of an external low frequency wave applied to the region being examined.
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40. A method of detecting one of tumors, lesions, or abnormal growths in a human body comprising the steps of:
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introducing microbubbles into a region of the body to be examined, wherein said microbubbles infuse into both healthy tissue and tumor tissue; applying high frequency sound waves to the region to be examined thereby causing an acoustic spectrum to be returned from the microbubbles; applying an external low frequency pressure wave to the region to be examined; monitoring at least one characteristic of the acoustic spectrum of said microbubbles in response to the applied external compressional wave; and ascertaining the presence of tumors, lesions, or abnormal growths from changes in the spectral characteristics between the healthy tissue and tumor tissue. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 53, 54)
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49. A method according to 40 wherein the probing low frequency wave operates in cooperation with ultrasound imaging such that the images are sampled at specific times during or related to the probing excitation cycle.
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50. A method according to 40 wherein the external static compressional wave is caused by the infusion of a liquid or gas into the region being examined resulting in probing pressure changes.
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51. A method according to 50 wherein the infusion of said liquid includes microbubbles.
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52. A method according to 51 wherein said liquid is injected via one of a syringe and a catheter.
Specification