Enhanced ultrasound detection with temperature-dependent contrast agents

a technology of contrast agent and ultrasound detection, which is applied in the field of ultrasound detection and imaging, can solve the problems of inability to detect pathological changes on or near vascular surfaces, the temperature-dependent ultrasound velocity of perfluorocarbon liquid has not been suggested to have any applicability in ultrasound imaging systems, and the detection of pathological changes may be compromised, etc., to achieve enhanced contrast imaging, little or no detectable change in acoustic reflectivity, and sensitive measurement of ultrasound reflectivity

Inactive Publication Date: 2007-11-01
BARNES JEWISH HOSPITAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010] Accordingly, the inventors herein have succeeded in discovering that changing the temperature of nanoparticles which contain a nongaseous fluorocarbon liquid and which are bound to a target, produces a detectable change in acoustic reflectivity of the target. Non-targeted regions which are adjacent to the target, but are not bound by the nanoparticles, show little or no detectable change in acoustic reflectivity. As a result, the temperature-dependent change in acoustic reflectivity of site-targeted nanoparticles provides a sensitive measurement of ultrasound reflectivity and provides enhanced contrast imaging.
[0014] In one aspect of the present invention, the change in temperature can be produced by energizing the bound nongaseous nanoparticles to increase temperature of the bound substance and enhance acoustic reflectivity of the target. The nanoparticles can be energized by ultrasound, shortwave, microwave, magnetic radiation, electromagnetic energy or a combination thereof.
[0015] In another aspect of the present invention, the temperature of the bound nanoparticles can be decreased to produce a measurable decrease in acoustic reflectivity of the target.

Problems solved by technology

One of the challenges confronting the use of site-targeted contrast agents is the sensitive detection and differentiation of the particles from the surrounding soft tissue.
Detection of pathological changes on or near vascular surfaces may be compromised because the targeted substrate itself is echogenic or the signal from that surface may be somewhat view or angle dependent.
Furthermore, the contrast agent may manifest velocities too slow for the sensitivity of Doppler techniques.
Nevertheless, the temperature-dependence of ultrasound velocity in perfluorocarbon liquids has not, heretofore, been suggested to have any applicability in ultrasound imaging systems.

Method used

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  • Enhanced ultrasound detection with temperature-dependent contrast agents
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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0081] This example illustrates the measurement of temperature dependence of ultrasound velocity in perfluorooctane, perfluorodichlorooctane and perfluorooctylbromide.

[0082] Ultrasound velocities were determined using a 25 MHz, Panametrics V324 spherically focused transducer. Measurements were made for perfluorooctane, perfluorodichlorooctane or perfluorooctylbromide at discrete temperatures by placing 8 mL of fluorocarbon in a sealed, vertically mounted sample chamber in heated water bath. The back of the chamber consisted of a stainless steel reflector, which extended past the fully enclosed well to allow for water-path and sample-path measurements. The chamber was mounted so that the stainless steel reflector was perpendicular to the insonifying beam.

[0083] The times of flight from the transducer to front wall of the chamber and from the transducer to the stainless steel plate were determined for nine independent locations over the sample. The speeds of sound were then averaged...

example 2

[0085] This example illustrates the preparation of a biotinylated microemulsion for avidin-biotin targeting.

[0086] A biotinylated emulsion was prepared by incorporating biotinylated phosphatidylethanolamine into the outer lipid monolayer of a perfluorocarbon microemulsion. The microemulsion was prepared containing perfluorooctane (40% w / v, 3M), vegetable oil (2% w / v) a surfactant co-mixture (2.0%, w / v) and glycerin (1.7%, w / v) in water as follows. The surfactant co-mixture was prepared by dissolving 64 mole % lecithin (Pharmacia, Inc), 35 mole % cholesterol (Sigma Chemical Co.) and 1 mole % N-(6-(biotinoyl)amino) hexanoyl)-dipalmitoyl-L-alpha-phosphatidyl-ethanolamine, Pierce, Inc.) in chloroform. The chloroform-lipid mixture was evaporated under reduced pressure, dried in a 50° C. vacuum oven overnight and dispersed into water by sonication. The suspension was then transferred into a blender cup (Dynamics Corporation of America) with the fluorocarbon, vegetable oil, glycerin and d...

example 3

[0087] This example illustrates a method which can be used to prepare an emulsion in which the nanoparticles are conjugated with an F(ab) fragment.

[0088] Targeting of emulsions can be achieved by direct chemical conjugation of an antibody to the nanoparticle through a primer material incorporated into the lipid monolayer. The perfluorocarbon nanoparticle contrast agent is prepared as described in Example 1.

[0089] F(ab) fragments are generated and isolated using an immunopure F(ab) preparation kit (Pierce, Rockford, Ill.). Briefly, IgG is dialyzed into 20 mM phosphate / 10 mM EDTA buffer (pH 7.0), concentrated to 20 mg / ml and digested by immobilized papain. Solubilized F(ab) is purified from Fe fragments and undigested IgG protein using a protein A column. F(ab) fragments is purified from excess cysteine using a G25-150 column and deoxygenated phosphate buffer (pH 6.7). Fraction identity is confirmed by routine SDS-PAGE procedures.

[0090] F(ab) fractions are pooled and combined with ...

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Abstract

Methods and devices for enhanced ultrasound detection based upon changing temperature and ultrasound reflectivity of a temperature-dependent contrast agent bound to an ultrasound target are disclosed. The methods and devices can be used for enhanced imaging alone or in conjunction with drug delivery, with therapeutic approaches such as hyperthermia or cryotherapy or with other imaging modalities.

Description

BACKGROUND OF THE INVENTION [0001] (1) Field of the Invention [0002] This invention relates generally to ultrasound detection and imaging and, more particularly, to novel compositions, methods and devices for detecting a change in ultrasound reflectivity based upon changing the temperature of a temperature-dependent contrast agent bound to the target. [0003] (2) Description of the Related Art [0004] Molecular imaging can enhance the utility of traditional clinical imaging by allowing specific detection of molecular markers in tissues using site-targeted contrast agents (Weissleder, Radiology 212:609-614, 1999). Three approaches to site-targeted ultrasonic agents have been reported and these are based upon the use of liposomes (Alkan-Onyuksel et al., J. Pharm. Sci 85:486-490, 1996; Demos et al., J. Pharm. Sci. 86:167-171, 1997; Demos et al., J. Am. Col. Cardiol. 33:867-875, 1999), the use of microbubbles (Mattrey et al, Am. J. Cardiol. 54:206-210, 1984; Unger et al., Am. J. Cardiol. ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61B5/00A61B5/055G01R33/28A61B8/00A61K9/133A61K49/00A61K49/04A61K49/22A61K51/00
CPCA61K49/223Y10S514/938Y10S514/937A61K49/226
Inventor LANZA, GREGORYWICKLINE, SAMUELHALL, CHRISTOPHER
Owner BARNES JEWISH HOSPITAL
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