text:
Prof. Joe Heithaus Remembers Author Maurice Sendak
May 9, 2012
"Maurice Sendak, for me, embodied the pleasure of curling in next to your child and reading something that could delight both of you," Joseph Heithaus tells the Christian Science Monitor. A tribute to Sendak, who died yesterday, includes comments from Heithaus, "a DePauw University professor, poet, and father of four," as the article notes.
"His youngest, now 10, he says, 'still wants her childhood story books read aloud at night, and just last week we read again Chicken Soup with Rice.' That Sendak poem, he says, 'even outside its hilarious illustrations, does just what a poem should do. It sets up a pattern and then surprises you again and again.' Professor Heithaus says the Sendak work, working similarly to a ghazal, an ancient Persian poetic form, incites the reader to play along. 'What child hearing that book aloud doesn't join you in the refrain –- Chicken Soup with Rice?' he says."
Sendak's works included the popular children's book, Where the Wild Things Are.
You'll find the full article by Gloria Goodale at the Monitor's website.
Joe Heithaus, University Professor and professor of English at DePauw University, published a collection of poems, Poison Sonnets, earlier this year. He is one of five "Airpoets," whose poems have been integrated into stained-glass window murals in the Indianapolis International Airport and are featured in two books, Rivers, Rails and Runways and Airmail.
Learn more about Professor Heithaus in this previous story.
Source: Christian Science MonitorBack


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Database software
Lead story: Do-it-all databases
Microsoft Access 2007
Filemaker Pro 10 Advanced
Corel Paradox X4
Alpha Five Version 9 Platinum
askSam Professional Version 7
Pros: Robust Web capabilitiesCons: Steep learning curve, expensiveFeatures: A-Performance: B+Ease of Use: CValue: CPrice: $399
If you have all the time in the world to learn a personal database, Alpha Five Version 9 Platinum is for you. However, if you want an easy-to-use program that you can learn as you go along, you might want to try one of the other databases in this review.
You can tell a lot about a database by the size of the reading material associated with it. Maybe I'm not a strong reader, but I don't see anything pleasant about a 961-page manual entitled, "Alpha Five Made Easy." A second book that came with the $399 Alpha Five explained why there is so much reading material: Alpha Five is a lot more than a database. It's also a tool for designing extensive Web applications with little or no programming. All you need is time to read and learn.
Like FileMaker, Alpha Five has a big developer community. However, unlike FileMaker, Alpha Five provides far fewer templates and seems to target medium to advanced users. Alpha Five has wizards, named Genies, that are easy to use and are relatively intuitive. However, these Genies are less refined than their FileMaker counterparts, and their interfaces are a little more cluttered than those in FileMaker and Access.
Nonprogrammers will have a hard time with Alpha Five, but you can still create powerful applications without scripting. All you have to do is what I did, spend a lot of time reading help files and studying the examples. I usually can figure out most things on my own, but I needed help with Alpha Five, particularly in understanding the Web applications that this software is capable of performing or even designing.
Alpha Five has a more cluttered and overwhelming environment than its competitors but still manages to pull off a sleek and modern look. You can now add buttons and images that are conditional on data in browse views. For example, I was able to easily add a button that would send an e-mail message to a person in that row. Likewise, you can configure a button to bring up a photo from a connected personnel database.
Other important features in Alpha Five include a Cascading Style Sheet builder for better Web form designs. Extremely strong client/server desktop support now lets you work directly with SQL Server databases. And a query optimizer for working with SQL data is new, as is the ability to build highly responsive Web 2.0/Asynchronous JavaScript and Extensible Markup Language applications in less time than in Visual Studio, Ruby or PHP.
Perhaps the most important feature for government agencies is a well-designed Web Security framework, which lets you define privileges for users and groups for pages or groups of pages in your Web application.
A new feature named Super Controls lets you place live reports, Web content and PDF documents directly into forms. Alpha Five can create virtual tables, XML Parser and HTML memo fields with hyperlinks.
However, nothing with Alpha Five is easy. And that includes testing our spreadsheet file. Of four ways to input an Excel file, the least difficult was to make a copy of the data you want from Excel and paste it into a new sheet in Excel. Then save that new sheet as a DBF IV file. Finally in Alpha Five, add the DBF file to your database. In FileMaker and Access, all I had to do was navigate to the document and click Open.
FileMaker's simple-to-learn nature, coupled with its robust template library, SQL capabilities and instant Web publishing, makes it the better choice for typical small-agency users. But Alpha Five has FileMaker beat when it comes to advanced features, such as script building and Web application development.
Alpha Software, 617-838 4488, www.alphafive.com
About the Authors
Carlos A. Soto is a former GCN Lab technology analyst.
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subset: commoncrawl


text:
Area/Code takes advantage of today's environment of pervasive technologies and overlapping media to create new kinds of gameplay. We are inspired by both the future potential of ubiquitous networked computing and the long historical tradition of games as social interaction.
Area/Code games highlight the connections between the interactive systems and imaginary landscapes inside of games and the real world around them. These connections can take many forms:
- Facebook games that create innovative new forms of social interaction
- online games that respond to broadcast TV in real time
- game systems that explore real-world social issues
- urban environments transformed into spaces for public play
- game events driven by real-world data
Area/Code works with game publishers like Electronic Arts and Ubisoft. We also work with advertising agencies, media firms, non-profit organizations, universities, and large consumer brands. Clients include: Nike, Disney, CBS, Nokia, MTV, The Discovery Channel, A&E, The History Channel, JWT, Cramer-Krasselt, Deutsch, SS+K, the National Association of Public Administration, the UK Department for Transport, and the Knight Foundation.
Projects have been awarded at the Clios, the One Show, OMMA and the Future of Marketing Summit. Area/code and its work have been covered in the Wall Street Journal, Creativity, The New York Times, Businessweek, The Chicago Tribune, MTV, Ad Age, and some of our favorite blogs including Joystiq, Kotaku, boingboing and PSFK.
The company was founded in early 2005 by Frank Lantz and Kevin Slavin; it has an HQ in Manhattan at 45 West 21st Street, Suite 3C.
Big Games are games that spill out over the edges of our screens and devices to blend with the real world in new and surprising ways.
Big Games excavate vast possibility spaces out of compact rulesets.
Big Games are building a future in which socially aware networks, smart objects, location sensing and mobile computing open up new ways for people to play.
Big Games build on thousands of years of games as a stylized form of social interaction
Big Games use technology, but are not subservient to it.
Big Games are made out of people, connections, ideas, situations, and events.
Big Games have computers inside of them, not the other way around.
Big Games create a conscious confusion between the real and the imaginary, between ideas and objects, between information and space.
Big Games transform the physical, social, and media spaces around us into a shared gameworld brought to life by the choices and actions of the players.
Big Games run the gamut from purely abstract formal systems to richly rendered narrative experiences.
Big Games connect people to people whether they are designers, players, strangers, rivals or friends.
Big Games are human-powered software for cities, life-size collaborative hallucinations, and serious fun.


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April 15 - 21, 2013
SKF warmly invites you to visit our booth at this years Bauma exhibition in Munich.
Our exhibits will be presented in an 'application led' format, clearly demonstrating where SKF products can add value for our customers for a wide variety of machine types.
The SKF booth will provide an opportunity to learn about SKF's wide portfolio of offers for Mining, Construction, Monitoring and Service and to discuss potential requirements with our specialist team. The exhibition is being presented under the overall theme: "The power of knowledge engineering."
Alongside our existing offers for mining & construction, such as our automated lubrication systems and the recently launched heavy duty hydraulic seals, we will be presenting a selection of exciting and innovative new products, including:
- New simple electrical multi-line grease pump P 502 - compact and economical for small machines
- New datalogger pump P 243 - to control warranty claims
- New Hose tear off control unit for big hydraulic excavators - simple electrical detection of hose tears
We hope that you can make it to the show and look forward to welcoming you to the SKF booth F7.709/4!
About bauma
With giant machines on 555.000 m² of exhibition space with 3,256 exhibitors and 420,000 visitors - bauma is the largest and perhaps most impressive trade fair
in the world. This is the 30th edition of this international trade fair for building material machines, mining machines and construction machines and vehicles.
The trade show is open from 15th -21st of April, in Munich, Germany. Link to website: http://www.bauma.de/en/home/startseite.php


text: Is there something hot in here or is it just these guys? The New York Post has shots from this year's nationwide firefighter calendar, and we can't say we minded looking through the gallery of our country's shirtless heroes. Above is Mr. Minneapolis (otherwise known as Justin Reid) and Mr. New York (real name Philip Sylvester). Check out the rest at The Post.


text:
I design and develop User Interfaces.
I'm good at HTML5 & CSS, LESS, jQuery, LAMP, Cordova and I love web standards.
You may look at my portfolio and if you believe I am the right man for the job, feel free to contact me by mail (email@example.com), phone (at +40 727 343nope 191), Skype (bynopecolor.ro) or by filling this quick contact form.
Thank you!


text:
TypeSolution Brief Market Guide Guide Case Study eBook Video Data Sheet Infographic White Paper Webinar Tool Podcast Incident Report Finance Partners Report Threat Intelligence
TopicsManaged Detection and Response Best Practice Threat Intelligence Ransomware Malware Regulatory Compliance GDPR Suspicious Activity Partners Endpoint Risk Advisory Managed Prevention Vulnerability Scanning Insider Threats Cybersec Decoded
IndustriesLaw Healthcare Finance Manufacturing Retail Technology
Industry: Healthcare
Ready to get started?
Get Started
We're here to help.
Reach out to schedule a meeting and learn more about our Managed Detection and Response, Risk Advisory and Managed Prevention capabilities.


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My husband and I are pretty lucky. We own a yachting business that allows us to travel all over the country. We've been up and down the Florida coast and just recently made a trip to New York. Traveling is something that we enjoy, so when we were looking to expand, one of the things that attracted us to our current home based internet business is the fact that it integrated nicely into our active lifestyle.
When it comes to starting a home based business, you certainly have a lot of choices. The internet has opened a lot of doors for people and has made it possible to start any kind of business you can imagine. If you love making wooden toys, you can start a home based internet business selling your crafts online. The possibilities are endless.
When it comes to achieving your life goals, however, you want to make sure your business fits in with the kind of lifestyle you want to create for yourself. If you are free birds, like my husband and I, who love to travel, then a home based business that requires you to stay home and produce a product is probably not the best business for you. For travel lover, an internet based business is the best option for you.
A home based internet business offers several distinct advantages over other types of home based businesses. The major advantage is that you won't be tied down. If you have a cell phone and a laptop, you'll be able to run your business wherever there is an internet connection. This means, if you suddenly want to pick up and take a road trip to California, you'll have the freedom to do so.
If you tap into the right home internet based opportunity, then you will also be able to make money even if you are not actively working your business. I am a firm believer in having multiple streams of income. But just as important is the fact that your business should also provide ways to generate passive income.
Passive, or residual, income is money that you continue to earn long after you have put in the initial effort to generate it. A prime example of this is book authors earn royalties on their books years after they first wrote and published them. Having streams of passive income in your work at home internet business makes it so your time and your income aren't so tightly wound together. This provides even more freedom to come and go as you please which is particularly important as we draw closer to our retirement years.
When evaluating home based internet business opportunities, it is important to make sure the business will fit into your active lifestyle. My husband and I settled on online business because it provided us with the maximum amount of freedom, offered opportunities for passive income, and didn't require us to deal will selling a product or managing inventory.


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Bathmate Hydromax X40 Review – The Original Water Pump
The Bathmate Hydromax X40 has been dubbed the best penis pump on the planet and for good reason. Bathmate is one of the leading manufacturers of pumps and made a huge hit with the X40's former model, the X30. With the introduction of the X40, users will be able to enjoy better suction, faster growth and the utmost in comfort. Let's take a look into the product with this immersive Bathmate Hydromax X40 review.
What's New
At first glance, Hydromax X40 provides a noticeable 15 percent enlargement over previous models. This allows those with already large penises to be able to enjoy all of the benefits of the pump with comfort. There is no squeezing yourself into the tube anymore. It is a great fit that will accommodate almost any size. The real improvement will be seen with the suction power that has been increased drastically.
35% More Suction
The Bellows Pump has been enhanced so that the Hydromax produces 35 percent more suction force. This alone allows users to see gains much faster than any other product on the market. Now, it takes 1/3 less of the time it used to take to see an increase in growth.
Swivel Bellows
Rotating the pump is easy with the 360 degree chamber. Users can simply view their penis through the clear, tinted chamber to ensure that they are snug inside of the tube and that they are fully erect.
Latch Valve
Want to take a shower with the pump? Now, the Super Flow Latch will ensure that you are able to use the Bathmate Hydromax X40, while being soaking wet. This is by far the most comfortable, private option. With the valve, the pump will still stay flush against a person's skin and not lose its suction power.
Growth Chart
No pump would be complete without a way to measure positive growth. Thanks to the clear tube, it is possible to see your penis and measure it along the guidelines on the outside of the cylinder. Now, you will be able to determine if growth has occurred and will be able to have a solid metric to determine just how much gains you have truly seen.
New Sealing
Rounding out this Bathmate review is the Bellows new sealing technology. This ensures that all of the pumping pressure is never lost when using the device. A soft seal ensures that the groin is never irritated during use and it even comes apart for easy cleaning.
As seen within this Bathmate Hydromax X40 review, this is the ideal pump for seeing positive penis size gains. With the great sealing of the Bellows system and the increased suction, it is easier to force blood into the penis and see the positive growth gains that users want. In fact, many users boast positive gains in a few months' time and put all of their trust in Bathmate to help them reach the girth they have always wanted. With the most advanced penis pump technology on the market put into the Bathmate Hydromax X40, this is the ideal pump for anyone that wishes they were just a little larger. Shipment is even done discretely so that users never have to let others know about their newfound growth.


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Gaseous ultrasound contrast media and method for selecting gases for use as ultrasound contrast media
Disclosed herein are agents for enhancing the contrast in an ultrasound image. These agents are extremely small bubbles, or "microbubbles," comprised of specially selected gases. The microbubbles described herein exhibit long life spans in solution and may be produced at a size small enough to traverse the lungs, thus enabling improved ultrasound imaging of the cardiovascular system and other vital organs. Also disclosed herein is a method for selecting gases from which contrast agents may be produced. The method is based on calculations using inherent physical properties of gases and describes a means to associate the properties of a gas with the time for dissolution of microbubbles comprised of the gas.
Latest Amersham Health A/S Patents:
This is a continuation of application Ser. No. 08/900,986, filed Jul. 25, 1997, now abandoned, which is a continuation of application Ser. No. 08/466,104 filed Jun. 6, 1995, now abandoned, which is a continuation of application Ser. No. 08/380,085 filed Jan. 30, 1995, now U.S. Pat. No. 5,558,854, which is a divisional of application No. 07/936,011 filed Sep. 2, 1992, now abandoned, which is a continuation-in-part of application Ser. No. 07/893,657 filed Jun. 5, 1992, now U.S. Pat. No. 5,409,688, which is a continuation-in-part of application Ser. No. 07/761,311 filed Sep. 17, 1991, now abandoned.DESCRIPTION
This invention relates to agents that enhance the contrast in an ultrasound image generated for use in medical diagnosis. The contrast-enhancing media disclosed herein are comprised of extremely small gas bubbles which are present in a solution that is infused into the body during or just before an ultrasound image is generated. This invention is also directed to a method for enhancing such images by selecting gases from which a collection of free gas microbubbles can be prepared that have novel and superior properties. These microbubbles, composed of the gases whose selection is enabled by the process of this invention, may be extremely small in size and yet survive in the bloodstream long enough to allow contrast-enhanced imaging of parts of the cardiovascular system, peripheral vascular system, and vital organs previously believed to be inaccessible to free gas microbubbles.BACKGROUND
When using ultrasound to obtain an image of the internal organs and structures of a human or animal, ultrasound waves—waves of sound energy at a frequency above that discernable by the human ear—are reflected as they pass through the body. Different types of body tissue reflect the ultrasound waves differently and the reflections, often aptly described as "echoes," that are produced by the ultrasound waves reflecting off different internal structures are detected and converted electronically into a visual display. This display may prove invaluable to a physician or other diagnostician in several ways, including evaluating the progression of cardiovascular disease or the existence or nature of a tumor.
For some medical conditions, obtaining a useful image of the organ or structure of interest is especially difficult because the details of the structure may not be adequately discernible from the surrounding tissue in an ultrasound image produced by the reflection of ultrasound waves absent a contrast-enhancing agent. Additionally, traditional ultrasound images are notoriously poor in quality and resolution. For these reasons, detection and observation of certain physiological conditions may be substantially improved by enhancing the contrast in an ultrasound image by infusing an agent into an organ or other structure of interest. In other cases, detection of the movement of the contrast-enhancing agent itself is particularly important. For example, a distinct blood flow pattern that is known to result from particular cardiovascular abnormalities may only be discernible by infusing a contrasting agent into the bloodstream and observing the dynamics of the blood flow.
Medical researchers have made extensive investigation into the use of solids, gases and liquids in an attempt to discover ultrasound contrast-enhancing agents suitable for particular diagnostic purposes. Composite substances such as gelatin encapsulated microbubbles, gas-incorporated liposomes, sonicated partially denatured proteins and emulsions containing highly fluorinated organic compounds have also been studied in an attempt to develop an agent that has certain ideal qualities, primarily, stability in the body and the ability to provide significantly enhanced contrast in an ultrasound image.
Small bubbles of a gas, termed "microbubbles," are readily detected in an image produced using standard ultrasound imaging techniques. When infused into the bloodstream or a particular site in the body, microbubbles enhance the contrast between the region containing the microbubbles and the surrounding tissue.
A substantial amount of the research effort directed at contrast-enhancing agents has focused on the use of extremely small gas bubbles. Investigators have long known that free gas bubbles provide a highly effective contrast agent because a gas bubble has unique physical characteristics that affect ultrasound energy as it is directed through the body. The advantages offered by free gas bubbles as opposed to liquid or solid agents that exhibit contrast enhancement is described in detail below in the context of the discussion of ultrasound diagnostic techniques.
Despite the known advantages, however, the rapid dissolution of free gas bubbles in solutions such as blood or many aqueous intravenous solutions, severely limits their use as an ultrasound contrast-enhancing agent. The most important limitations are the size of the microbubble and the length of time that a microbubble will exist before dissolving into the solution.
Examining the size requirements for microbubbles more closely, the gas bubbles must, of course, be sufficiently small that a suspension of the bubbles does not carry the risk of embolism to the organism in which they are infused. At the same time, extremely small free gas bubbles composed of the gases generally used in ultrasound contrast imaging dissolve into solution so rapidly that their image-enhancing capability exists only immediately proximate to the infusion site. An additional obstacle exists for ultrasound imaging of the cardiovascular system. Medical researchers have studied the time required for microbubbles composed of ordinary air, pure nitrogen, pure oxygen, or carbon dioxide, to dissolve into solution. Microbubbles of these gases that are sufficiently small to be able to pass through the lungs and reach the left heart, less than about 8 microns in diameter, have a life span of less than approximately 0.25 seconds. Meltzer, R. S., Tickner, E. G., Popp, R. L., "Why Do the Lungs Clear Ultrasonic Contrast?" Ultrasound in Medicine and Biology, Vol. 6, p. 263, 267 (1980). Since it takes over 2 seconds for blood to pass through the lungs, microbubbles of these gases would be fully dissolved during passage through the lungs and would never reach the left heart. Ibid. Primarily because of this tradeoff between bubble size and life span, many researchers concluded that free gas microbubbles were not useful as a contrast-enhancing agent for ultrasound diagnosis of certain parts of the cardiovascular system.
However, the ultrasound contrast-enhancing media described herein comprises microbubbles, composed of the biocompatible gases whose selection is also provided by this invention, that are sufficiently small that they pass through the pulmonary capillary diameter of approximately 8 microns and thereby allow contrast-enhanced ultrasound diagnosis of the left chambers of the heart. The free gas microbubbles survive in the bloodstream long enough that they may be peripherally intravenously infused, travel through the right heart, through the lungs, and into the left cardiac chambers without dissolving into solution. Additionally, certain of these media have extremely long persistence in solution and will enable contrast-enhancement of many other organs and structures.
This invention overcomes many of the inherent limitations thought to exist with the use of free gas microbubbles by providing, in part, a method for selecting special gases based on particular physical criteria such that microbubbles composed of these gases do not suffer from the same limitations as the microbubbles previously investigated. Therefore, it has been discovered that the ultrasound contrast-enhancing media described herein comprising a composition of microbubbles produced using a biocompatible gas or combination of gases selected by the physical and chemical parameters disclosed herein can exist for a sufficient length of time and be of sufficiently small size that their stability in the bloodstream allows enhanced ultrasound contrast imaging of particular structures in the body previously thought inaccessible to free gas microbubbles.
By using the term "biocompatible gas" I mean a chemical entity which is capable of performing its functions within or upon a living organism in an acceptable manner, without undue toxicity or physiological or pharmacological effects, and which is, at the temperature of the living organism, in a state of matter distinguished from the solid or liquid states by very low density and viscosity, relatively great expansion and contraction with changes in pressure and temperature, and the spontaneous tendency to become distributed uniformly throughout any container. The following Table contains the assumed body temperatures for various living organisms:.Rectal Temperature Organism (degree Fahrenheit) Swine (Sus Scrofa) 101.5-102.5 Sheep (Ovis sp.) 101-103 Rabbit (Oryctolaqus cuniculus) 102-103.5 Rat (Tattus morvegicus) 99.5-100.6 Monkey (Macaca mulatta) 101-102 Mouse (Mus Musculus) 98-101 Goat (Capra hircus) 101-103 Guinea pig (Cavia porcellus) 102-104 Hamster (Mesocricetus sp.) 101-103 Ham (Homo sapiens) 98.6-100.4 Horse (Equus sp.) 101-102.5 Dog (Canin familiaris) 101-102 Baboon (Papio) 98-100 Cat (Felis catus) 101-102 Cattle (Bos taurus) 101.5-102.5 Chimpanzee (Pan) 96-100 Techniques For Measuring Ultrasound Contrast-enhancement Phenomena
To more fully appreciate the subject matter of the present invention, it is useful to describe what is presently known about the technology of ultrasound imaging and to review the search for improved ultrasound contrast-enhancing agents in that light.
Materials that are useful as ultrasound contrast agents operate by having an effect on ultrasound waves as they pass through the body and are reflected to create the image from which a medical diagnosis is made. In an attempt to develop an efficient image-contrast agent, one skilled in the art recognizes that different types of substances affect ultrasound waves in different ways and to varying degrees. Moreover, certain of the effects caused by contrast-enhancing agents are more readily measured and observed than others. Thus, in selecting an ideal composition for a contrast-enhancing agent, one would prefer the substance that has the most dramatic effect on the ultrasound wave as it passes through the body. Also, the effect on the ultrasound wave should be easily measured. There are three main contrast-enhancing effects which can be seen in an ultrasound image: backscatter, beam attenuation, and speed of sound differential. Each of these effects will be described in turn.
When an ultrasound wave that is passing through the body encounters a structure, such as an organ or other body tissue, the structure reflects a portion of the ultrasound wave. Different structures within the body reflect ultrasound energy in different ways and in varying strengths. This reflected energy is detected and used to generate an image of the structures through which the ultrasound wave has passed. The term "backscatter" refers to the phenomena in which ultrasound energy is scattered back towards the source by a substance with certain physical properties.
It has long been recognized that the contrast observed in an ultrasound image may be enhanced by the presence of substances known to cause a large amount of backscatter. When such a substance is administered to a distinct part of the body, the contrast between the ultrasound image of this part of the body and the surrounding tissues not containing the substance is enhanced. It is well understood that, due to their physical properties, different substances cause backscatter in varying degrees. Accordingly, the search for contrast-enhancing agents has focused on substances that are stable and non-toxic and that exhibit the maximum amount of backscatter.
Making certain assumptions about the way a substance reflects ultrasound energy, mathematical formulae have been developed that describe the backscatter phenomenon. Working with these formulae, a skilled researcher can estimate the ability of gas, liquid, and solid contrast-enhancing agents to cause backscatter and the degree to which a particular substance causes measurable backscatter can be compared with other substances based on the physical characteristics known to cause the backscatter phenomenon. As a simple example, the ability of substance A to cause backscatter will be greater than substance B, if, all other factors being equal, substance A is larger than substance B. Thus, when both substances are encountered by an ultrasound wave, the larger substance scatters a greater amount of the ultrasound wave.
The capability of a substance to cause backscatter of ultrasound energy also depends on other characteristics of the substance such as its ability to be compressed. Of particular importance is the dramatic increase in backscatter caused by gas bubbles due to the bubble resonance phenomenon which is described below. When examining different substances, it is useful to compare one particular measure of the ability of a substance to cause backscatter known as the "scattering cross-section."
The scattering cross-section of a particular substance is proportional to the radius of the scatterer, and also depends on the wavelength of the ultrasound energy and on other physical properties of the substance, J. Ophir and K. J. Parker, Contrast Agents in Diagnostic Ultrasound, Ultrasound in Medicine & Biology, vol. IS, n. 4, p. 319, 323 (1989).
The scattering cross-section of a small scatterer, a, can be determined by a known equation: σ = [ 4 9  π   ( a 2  ( ka ) ) 4 ]  [ &LeftBracketingBar; κ s - κ κ &RightBracketingBar; 2 + 1 3  &LeftBracketingBar; 3  ( ρ s - ρ ) 2   ρ s - ρ &RightBracketingBar; 2 ]
where &kgr;=2&pgr;/&lgr;, where &lgr; is the wavelength; a=the radius of the scatterer; &kgr;s=adiabatic compressibility of the scatterer; &kgr;=adiabatic compressibility of the medium in which the scatterer exists, &rgr;s=density of the scatterers and &rgr;=the density of the medium in which the scatterer exists. P. M. Morse and K. U. Ingard, Theoretical Acoustics, p. 427, McGraw Hill, New York (1968).
In evaluating the utility of different substances as image contrasting agents, one can use this equation to determine which agents will have the higher scattering cross-section and, accordingly, which agents will provide the greatest contrast in an ultrasound image.
Referring to the above equation, the first bracketed quantity in the above equation can be assumed to be constant for the purpose of comparing solid, liquid and gaseous scatterers. It can be assumed that the compressibility of a solid particle is much less than that of the surrounding medium and that the density of the particle is much greater. Using this assumption, the scattering cross section of a solid particle contrast-enhancing agent has been estimated as 1.75. Ophir and Parker, supra, at 325.
For a pure liquid scatterer, the adiabatic compressibility and density of the scatterer &kgr;s and the surrounding medium &kgr; are likely to be approximately equal which would, from the above equation, yield the result that liquids would have a scattering cross-section of zero. However, liquids may exhibit some backscatter if large volumes of a liquid agent are present presumably because the term a in the first bracketed quantity in the above equation may become sufficiently large. For example, if a liquid agent passes from a very small vessel to a very large one such that the liquid occupies substantially all of the vessel the liquid may exhibit measurable backscatter. Nevertheless, in light of the above equation and the following, it is appreciated by those skilled in the art that pure liquids are relatively inefficient scatterers compared to free gas microbubbles.
It is known that changes in the acoustic properties of a substance are pronounced at the interface between two phases, i.e., liquid/gas, because the reflection characteristics of an ultrasound wave change markedly at this interface. Additionally, the scatter cross-section of a gas is substantially different than a liquid or solid, in part, because a gas bubble can be compressed to a much greater degree than a liquid or solid. The physical characteristics of gas bubbles in solution are known and standard values for compressibility and density figures for ordinary air can be used in the above equation. Using these standard values, the result for the second bracketed term alone in the above equation is approximately 1014, Ophir and Parker supra, at 325, with the total scattering cross section varying as the radius a of the bubble varies. Moreover, free gas bubbles in a liquid exhibit oscillatory motion such that, at certain frequencies, gas bubbles will resonate at a frequency near that of the ultrasound waves commonly used in medical imaging. As a result, the scattering cross-section of a gas bubble can be over a thousand times larger than its physical size.
Therefore, it is recognized that gas micro bubbles are superior scatterers of ultrasound energy and would be an ideal contrast-enhancing agent if the obstacle of their rapid dissolution into solution could be overcome.
Another effect which can be observed from the presence of certain solid contrast-enhancing agents, is the attenuation of the ultrasound wave. Image contrast has been observed in conventional imaging due to localized attenuation differences between certain tissue types. K. J. Parker and R. C. Wang, "Measurement of Ultrasonic Attenuation Within Regions selected from B-Scan Images," IEEE Trans. Biomed. Enar. BME 30(8), p. 431-37 (1983); K. J. Parker, R. C. Wang, and R. M. Lerner, "Attenuation of Ultrasound Magnitude and Frequency Dependence for Tissue Characterization," Radiology, 153(3), p. 785-88 (1984). It has been hypothesized that measurements of the attenuation of a region of tissue taken before and after infusion of an agent may yield an enhanced image. However, techniques based on attenuation contrast as a means to measure the contrast enhancement of a liquid agent are not well-developed and, even if fully developed, may suffer from limitations as to the internal organs or structures with which this technique can be used. For example, it is unlikely that a loss of attenuation due to liquid contrast agents could be observed in the image of the cardiovascular system because of the high volume of liquid contrast agent that would need to be present in a given vessel before a substantial difference in attenuation could be measured.
Measurement of the attenuation contrast caused by microspheres of Albunex (Molecular Biosystems, San Diego, Calif.) in vitro has been accomplished and it has been suggested that in vivo attenuation contrast measurement could be achieved. H. Bleeker, K. Shung, J. Burnhart, "On the Application of Ultrasonic Contrast Agents for Blood Flowometry and Assessment of Cardiac Perfusion," J. Ultrasound Med. 9:461-471 (1990). Albunex is a suspension of 2-4 micron encapsulated air-filled microspheres that have been observed to have acceptable stability in vivo and are sufficiently small in size that contrast enhancement can occur in the left atrium or ventricle. Also, attenuation contrast resulting from iodipamide ethyl ester (IDE) particles accumulated in the liver has been observed. Under such circumstances, the contrast enhancement is believed to result from attenuation of the ultrasound wave resulting from the presence of dense particles in a soft medium. The absorption of energy by the particles occurs by a mechanism referred to as "relative motion." The change in attenuation caused by relative motion can be shown to increase linearly with particle concentration and as the square of the density difference between the particles and the surrounding medium. K. J. Parker, et al., "A Particulate Contrast Agent with Potential for Ultrasound Imaging of Liver," Ultrasound in Medicine & Biology, Vol. 13, No. 9, p. 555, 561 (1987). Therefore, where substantial accumulation of solid particles occurs, attenuation contrast may be a viable mechanism for observing image contrast enhancement although the effect is of much smaller magnitude than the backscatter phenomenon and would appear to be of little use in cardiovascular diagnoses.
An additional possible technique to enhance contrast in an ultrasound image has been proposed based on the fact that the speed of sound varies depending on the media through which it travels. Therefore, if a large enough volume of an agent, through which the speed of sound is different than the surrounding tissue, can be infused into a target area, the difference in the speed of sound through the target area may be measurable. Presently, this technique is only experimental.
Therefore, considering the three techniques described above for contrast enhancement in an ultrasound image, the marked increase in backscatter caused by free gas microbubbles is the most dramatic effect and contrast-enhancing agents that take advantage of this phenomenon would be the most desirable if the obstacle of their limited stability in solution could be overcome.The Materials Presently Used as Contrast-enhancing Agents
In light of what is known about the various techniques described above, attempts to develop a contrast-enhancing agent whose presence generates substantial contrast in an ultrasound image, and whose survival in vivo is sufficiently long to allow contrast-enhanced imaging of the cardiovascular system, has led to the investigation of a broad variety of substances—gases, liquids, solids, and combinations of these—as potential contrast-enhancing agents.
Typically, the solid substances that have been studied as potential contrast-enhancing agents are extremely small particles that are manufactured in uniform size. Large numbers of these particles can be infused and circulate freely in the bloodstream or they may be injected into a particular structure or region in the body.
IDE particles are solid particles that can be produced in large quantities with a relatively narrow size distribution of approximately 0.5-2.0 microns. Sterile saline injections of these particles may be injected and will tend to accumulate in the liver. Once a substantial accumulation occurs, contrast enhancement may be exhibited by either attenuation contrast or backscatter mechanisms. Although suspensions comprising these solid particles dispersed in a liquid may exhibit acceptable stability, the backscatter or attenuation effects are relatively minor compared to free gas bubbles and a substantial accumulation of the particles must occur before appreciable contrast is observed in an ultrasound image. Thus, use of these suspensions has been limited to certain cell types in which the particles have the tendency to coagulate because unless the suspension becomes highly concentrated in particular tissue, the contrast enhancement will be minor.
SHU-454 (Schering, A. G., West Berlin, Germany) is an experimental contrast-enhancing agent in powder form that, when mixed with a saccharide diluent, forms a suspension of crystals of various rhomboid and polyhedral shapes ranging in size from 5 to 10 microns. Although the precise mechanism by which these crystals enhance ultrasound contrast is not completely understood, it is suspected that the crystals may trap microbubbles in their structure or that the crystals themselves may backscatter ultrasound energy by an as-yet undetermined mechanism.
In another attempt to achieve a satisfactory agent, emulsions are prepared by combining a chemical species compatible with body tissue and a species that provides high ultrasound contrast enhancement. European Patent Application 0231091 discloses emulsions of oil in water containing highly fluorinated organic compounds that have been studied in connection with their possible use as a blood substitute and are also capable of providing enhanced contrast in an ultrasound image.
Emulsions containing perfluorooctyl bromide (PFOB) have also been examined. Perfluorooctyl bromide emulsions are liquid compounds known to have the ability to transport oxygen. PFOB emulsions have exhibited a limited utility as ultrasound contrast agents because of a tendency to accumulate in certain types of cells. Although the mechanism is not completely understood, PFOB emulsions may provide ultrasound contrast because of their high density and relatively large compressibility constant.
U.S. Pat. No. 4,900,540 describes the use of phospholipid-based liposomes containing a gas or gas precursor as a contrast-enhancing agent. A liposome is a microscopic, spherical vesicle, containing a bilayer of phospholipids and other amphipathic molecules and an inner aqueous cavity, all of which is compatible with the cells of the body. In most applications, liposomes are used as a means to encapsulate biologically active materials. The above reference discloses the use of a gas or gas precursors incorporated into the liposome core to provide a longer life span for the gas when infused into the body. Production of stable liposomes is an expensive and time consuming process requiring specialized raw materials and equipment.
As noted above, a critical parameter that must be satisfied by a microbubble used as a contrast-enhancing agent is size. Free gas microbubbles larger than approximately 8 microns may still be small enough to avoid impeding blood flow or occluding vascular beds. However, microbubbles larger than 8 microns are removed from the bloodstream when blood flows through the lungs. As noted above, medical researchers have reported in the medical literature that microbubbles small enough to pass through the lungs will dissolve so quickly that contrast enhancement of left heart images is not possible with a free gas microbubble. Meltzer, R. S., Tickner, E. G., Popp, R. L., "Why Do the Lungs Clear. Ultrasonic Contrast?" Ultrasound in Medicine and Biology, vol. 6, p. 263, 267 (1980).
However, cognizant of the advantages to be gained by use of microbubbles as contrast-enhancing agents by virtue of their large scattering cross-section, considerable attention has been focused on developing mixtures containing microbubbles that are rendered stable in solution. Enhancing the stability of gas microbubbles may be accomplished by a number of techniques.
Each of the following techniques essentially involves suspending a collection of microbubbles in a substrate in which a bubble of ordinary gas is more stable than in the bloodstream.
In one approach, microbubbles are created in viscous liquids that are injected or infused into the body while the ultrasound diagnosis is in progress. The theory behind the use of viscous fluids involves an attempt to reduce the rate at which the gas dissolves into the liquid and, in so doing, provide a more stable chemical environment for the bubbles so that their lifetime is extended.
Several variations on this general approach have been described. EPO Application No. 0324938 describes a viscous solution of a biocompatible material, such as a human protein, in which microbubbles are contained. By submitting a viscous protein solution to sonication, microbubbles are formed in the solution. Partial denaturation of the protein by chemical treatment or heat provides additional stability to microbubbles in the solution by decreasing the surface tension between bubble and solution.
Therefore, the above approaches may be classified as an attempt to enhance the stability of microbubbles by use of a stabilizing medium in which the microbubbles are contained. However, none of these approaches have addressed the primary physical and chemical properties of gases which have seriously limited the use of free gas microbubbles in ultrasound diagnosis, particularly with respect to the cardiovascular system. None of these approaches suggest that selection of the gases, by precise criteria, would yield the ability to produce stable microbubbles at a size that would allow transpulmonary contrast-enhanced ultrasound imaging.
The behavior of microbubbles in solution can be described mathematically based on certain parameters and characteristics of the gas of which the bubble is formed and the solution in which the bubble is present. Depending on the degree to which a solution is saturated with the gas of which the microbubbles are formed, the survival time of the microbubbles can be calculated. P. S. Epstein, M. S. Plesset, "On the Stability of Gas Bubbles in Liquid-Gas Solutions," The Journal of Chemical Physics, Vol. 18, n. 11, 1505 (1950). Based on calculations, it is apparent that as the size of the bubble decreases, the surface tension between bubble and surrounding solution increases. As the surface tension increases, the rate at which the bubble dissolves into the solution increases rapidly and, therefore, the size of the bubble decreases more and more rapidly. Thus, the rate at which the bubble shrinks increases as the size of the bubble decreases. The ultimate effect of this is that a population of small free gas microbubbles composed of ordinary air dissolves so rapidly that the contrast-enhancing effect is extremely short lived. Using known mathematical formula, one can calculate that a microbubble of air that is 8 microns in diameter, which is small enough to pass through the lungs, will dissolve in between 190 and 550 milliseconds depending on the degree of saturation of the surrounding solution. Based on these calculations, medical investigators studying the way in which the lungs remove ultrasound contrast agent have calculated the dissolution times of oxygen and nitrogen gas microbubbles in human and canine blood and have concluded that free gas microbubble contrast agents will not allow contrast-enhanced imaging of the left ventricle because of the extremely brief life of the microbubbles.
The physical properties of the systems that feature gas bubbles or gases dissolved in liquid solutions have been investigated in detail including the diffusion of air bubbles formed in the cavitating flow of a liquid and the scatter of light and sound in water by gas bubbles.
The stability of gas bubbles in liquid-gas solution has been investigated both theoretically, Epstein P. S. and Plesset M. S., On the Stability of Gas Bubbles in Liquid-Gas Solutions, J. Chem. Phys. 18:1505-1509 (1950) and experimentally, Yang W J, Dynamics of Gas Bubbles in Whole Blood and Plasma, J. Biomech 4:119-125 (1971); Yang W J, Echigo R., Wotton D R, and Hwang J B, Experimental Studies of the Dissolution of Gas Bubbles in Whole Blood and Plasma-I. Stationary Bubbles. J. Biomech 3:275-281 (1971); Yang W J, Echigo R., Wotton D R, Hwang J B, Experimental Studies of the Dissolution of Gas Bubbles in Whole Blood and Plasma-II. Moving Bubbles or Liquids. J. Biomech 4:283-288 (1971). The physical and chemical properties of the liquid and the gas determine the kinetic and thermodynamic behavior of the system. The chemical properties of the system which influence the stability of a bubble, and accordingly the life time, are the rate and extent of reactions which either consume, transform, or generate gas molecules.
For example, a well known reaction that is observed between a gas and a liquid takes place when carbon dioxide gas is present in water. As the gas dissolves into the aqueous solution, carbonic acid is created by hydration of the carbon dioxide gas. Because carbon dioxide gas is highly soluble in water, the gas diffuses rapidly into the solution and the bubble size diminishes rapidly. The presence of the carbonic acid in the solution alters the acid-base chemistry of the aqueous solution and, as the chemical properties of the solution are changed by dissolution of the gas, the stability of the carbon dioxide gas bubbles changes as the solution becomes saturated. In this system, the rate of dissolution of a gas bubble depends in part on the concentration of carbon dioxide gas that is already dissolved in solution.
However, depending on the particular gas or liquid present in the system, the gas may be substantially insoluble in the liquid and dissolution of a gas bubble will be slower. In this situation, it has been discovered that it is possible to calculate bubble stability in a gas-liquid system by examining certain physical parameters of the gas.BRIEF DESCRIPTION OF THE INVENTION
It has been discovered that it is possible to identify chemical systems where extremely small gas bubbles are not reactive in an aqueous solution. Relying on the method disclosed herein one skilled in the art may specially select particular gases based on their physical and chemical properties for use in ultrasound imaging. These gases can be used to produce the contrast-enhancing media that is also the subject matter of this invention. The microbubbles can be produced using certain existing techniques that use ordinary air, and can be infused as in a conventional ultrasound diagnosis.
The method that is the subject matter of this invention requires that calculations be made, consistent with the equations provided herein, based on the intrinsic physical properties of a gas and a liquid. Particularly, the density of a gas, the solubility of a gas in solution, and the diffusivity of a gas in solution, which in turn is dependent on the molar volume of the gas and the viscosity of the solution, are used in the equations disclosed below. Thus, by the method disclosed herein, the physical properties of a given gas-liquid system can be evaluated, the rate and extent of bubble collapse can be estimated, and gases that would constitute effective contrast-enhancing agents can be selected based on these calculations. Using existing techniques, substantially improved contrast-enhancing media may then be produced and used to improve the quality and usefulness of ultrasound imaging.DETAILED DESCRIPTION OF THE INVENTION
To understand the method of this invention, it is useful to derive the mathematical relationships that describe the parameters of a gas-liquid system and the effect on bubble stability that occurs when a value for one or more of these parameters is altered. It is assumed that, at an initial time, T0, a spherical gas bubble of gas X, with a radius of R0, is placed in a solution in which the initial concentration of gas X dissolved in the solution is equal to zero. Over some period of time, the bubble of gas X will dissolve into the solvent at which time its radius R will equal zero. Assume further that the solution is at constant temperature and pressure and that the dissolved gas concentration for a solution saturated with the particular gas is designated Cs. Thus, at T0, the concentration of the gas in the solution is zero, meaning that none of the gas has yet dissolved and all of the gas that is present is still contained within the bubble of radius R0.
As time progresses, due to the difference in the concentration of the gas in the bubble and the gas in solution, the bubble will tend to shrink as gas in the bubble is dissolved into the liquid by the process of diffusion. The change in bubble radius from its original radius of R0 to, after the passage of a particular amount of time, a smaller radius R is expressed by Equation (1), R R 0 = [ 1 - ( 2   DC s ρ   R 0 2 )  T ] 1 / 2
where R is the bubble radius at time T, D is the coefficient of diffusivity of the particular gas in the liquid, and &rgr; is the density of the particular gas of which the bubble is composed.
It follows that the time T required for a bubble to dissolve completely may be determined from Equation (1) by setting R/R0=0, and solving for T: T = R 0 2  ρ 2  DC s Equation   ( 2 )
This result qualitatively indicates that bubble stability, and hence life span, is enhanced by increasing the initial bubble size R0 or by selecting a gas of higher density &rgr;, lower solubility Cs in the liquid phase, or a lower coefficient of diffusivity D.
The diffusivity D of a gas in a liquid is dependent on the molar volume of the gas (Vm), and the viscosity of the solution (&eegr;) as expressed by a known Equation;
D=13.26×10−5·&eegr;−1.14·Vm−0.589 (Equation 3)
By substituting the expression for D given in Equation (3) into Equation (2) it is revealed that bubble stability is enhanced by using gases of larger molar volume Vm, which tend to have a higher molecular weight, and liquids of higher viscosity.
By way of example, a comparison of the stability of air microbubbles and microbubbles composed of gases specially selected by the method disclosed herein may be made. Taking the value of D for air in water at 22° C. as 2×10−5 cm−2sec−1 and the ratio Cs/&rgr;=0.02 (Epstein and Plesset, Ibid.), one obtains the following data for the time t for complete solution of air bubbles in water (unsaturated with air):TABLE I INITIAL BUBBLE DIAMETER, microns TIME, milliseconds 12 450 10 313 8 200 6 113 5 78 4 50 3 28 2 13 1 3
If the blood transit time from the pulmonary capillaries to the left ventricle is two seconds or more (Hamilton, W. F. editor, Handbook of Physiology, Vol. 2, section 2, CIRCULATION. American Physiology Society, Washington, D.C., p. 709, (1963)), and recognizing that only microbubbles of approximately 8 microns or less will be small enough to pass through the lungs, it is clear that none of these bubbles have a life span in solution long enough to be useful contrast agents for ultrasound contrast-enhanced imaging of the left ventricle.
The method of the present invention allows identification of potentially useful gases by comparing the properties of any particular gas, denoted gas X in the following description, to air. Taking Equations (2) and (3) above, a coefficient Q may be formulated for a particular gas X that will describe the stability of microbubbles composed of gas X in a given liquid. The value of the Q coefficient determined by this method for a particular gas X also can be used to determine the utility of gas X as an ultrasound contrast-enhancing agent as compared to ordinary air.
From Equation (2) above, an equation that describes the time for complete dissolution of a bubble of gas X compared to the same size bubble of ordinary air under identical conditions of solution temperature and solution viscosity may be written based on the physical properties of gas X and air: T x = T air  [ ρ x ρ air ]  [ ( C s ) air ( C s ) x ]  [ D air 13.26 × 10 - 5 · η - 1.14 · ( V m ) x - .589 ] Equation   ( 4 )
or, if D is known for gas X, T x = T air  [ ρ x ρ air ]  [ ( C s ) air ( C s ) x ]  [ D air D x ] Equation   ( 5 )
To formulate this equation so that the value Q may be obtained to enable comparison of gas X with air, the above equation may be rewritten:
Tx=QTair where Equation (6)
Q = [ ρ x ρ air ]  [ ( C s ) air ( C s ) x ]  [ D air D x ]
Assuming for comparison, a solution of water at 22 degrees C., the density, diffusivity, and solubility of air in the solution are known quantities which may be substituted into the above equation yielding: Q = 4.0 × 10 - 7  [ ρ x ( C x ) x  D x ] Equation   ( 7 )
Substituting Equation (3) into the above for gases whose diffusivity Dx is not readily known, and assuming that the viscosity term &eegr; below for water at 22 degrees C. is approximately equal to 1.0 cP, Q = 3.0 × 10 - 3  [ ρ x ( C s ) x  ( V m ) x - .589 ] Equation   ( 8 )
Thus, knowing the density, solubility and molar volume of a gas, this method allows the calculation of the value of the Q coefficient.
If Q is less than one, microbubbles of gas X will be less stable in a given solvent than microbubbles of air. If Q is greater than one, microbubbles formed of gas X are more stable than microbubbles of air and will survive in solution longer than air bubbles. All other properties being the same for a given microbubble size, the time for complete dissolution of a microbubble of gas X is equal to the time for complete dissolution of a microbubble of ordinary air multiplied by the Q coefficient. For example, if the Q coefficient for gas X is 10,000, a microbubble of gas X will survive 10,000 times as long in solution compared to a microbubble of air. A Q value can be determined for any gas in any solution assuming the quantities identified herein are known or can be estimated.
Different methods for determining or estimating values for the individual parameters of density, diffusivity, and solubility may be needed depending on the chemical structure of the gas. Values for these parameters may or may not be available from known scientific literature sources such as the Gas Encyclopedia or the tabulations published by the American Chemical Society. Values for the density of most gases are readily available from sources such as the Handbook of Chemistry and Physics, CRC Press, 72d Ed. (1991-92). Additionally, the solubility in water and molar volume of some gases has been measured with accuracy. In many cases however, calculations for the numerical values for molar volume and solubility may need to be calculated or estimated to provide the data used to determine the value of the Q coefficient for an individual gas by the method described above. An example of the calculation of Q values for a preferred selection of gases illustrates how the method of this invention can be applied to individual gases.
Generally, many fluorine-containing gases exhibit extremely low solubility in water, and have relatively high molecular weights, high molar volumes, and high densities. To determine the Q value for several gases, the solubility, molar volume and density of the individual gases are determined and the values are substituted into Equations (7) or (8) above.Determination of Gas Solubility for Fluorocarbons
This method for estimating the gas solubility of fluorocarbons uses extrapolation of the experimental data of Kabalnov A S, Makarov K N, and Scherbakova O V. "Solubility of Fluorocarbons in Water as a Key Parameter Determining Fluorocarbon Emulsion Stability," J. Fluor. Chem. 50, 271-284, (1990). The gas solubility of these fluorocarbons is determined relative to perfluoro-n-pentane which has a water solubility of 4.0×10−6 moles per liter. For a homologous series of non-branched fluorocarbons, the gas solubility may be estimated by increasing or reducing this value by a factor of about 8.0 for each increase or reduction in the number of additional —CF2— groups present in the molecule.Determination of Molar Volume
The molar volume (Vm) is estimated from the data of Bondi A., "Van der Waals Volumes and Radii," J. Phys. Chem. 68, 441-451 (1964). The molar volume of a gas can be estimated by identifying the number and type of atoms that make up the molecule of gas in question. By determining the number and type of atoms present in the molecule and how the individual atoms are bound to each other, known values may be applied for the molecular volume of the individual atoms. By considering the contribution of each individual atom and its frequency of occurrence, one may calculate the total molar volume for a particular gas molecule. This calculation is best demonstrated with an example.
It is known that a carbon molecule in an alkane carbon-carbon bond has a molar volume of 3.3 cubic centimeters per mole, a carbon atom in an alkene carbon-carbon bond has a molar volume of 10.0 cubic centimeters per mole, and when multiple fluorine atoms are bound to an alkane carbon, a fluorine atom has a molar volume of 6.0 cubic centimeters per mole.
Examining octafluoropropane, this molecule contains three carbon atoms in alkane carbon-carbon bonds (3 atoms at 3.3 cubic centimeters per mole) and 6 fluorine atoms bound to alkane carbons (6 atoms at 6.0 cubic centimeters per mole) hence, octafluoro-propane has a molar density of 58 cubic centimeters per mole.
Once density, molar volume, and solubility are determined, the Q value is calculated using Equation 8 above.
The following Table lists the Q value for a number of gases based on the calculations detailed above.TABLE II SOL- UBILITY MOLAR DENSITY micromoles/ VOLUME GAS kg/m3 liter cm3/mole Q Argon 1.78 1500 17.9 20 n-Butane 2.05 6696 116 5 Carbon Dioxide 1.98 33000 19.7 1 Decafluorobutane 11.21 32 73 13,154 Dodecafluoropentane 12.86 4 183 207,437 Ethane 1.05 2900 67 13 Ethyl ether 2.55 977,058 103 0.1 Helium 0.18 388 8 5 Hexafluorobuta-1,3- 9 (*) 2000 56 145 diene Hexafluoro-2-butyne 9 (*) 2000 58 148 Hexafluoroethane 8.86 2100 43 116 Hexafluoropropane 10.3 260 58 1299 Krypton 3.8 2067 35 44 Neon 0.90 434 17 33 Nitrogen ## ## ## 1 Octafluoro-2-butene 10 (*) 220 65 1594 Octafluorocyclobutane 9.97 220 61 1531 Octafluoropropane 10.3 260 58 1299 Pentane 2 1674 113 58 Propane 2.02 2902 90 30 Sulfur Hexafluoride 5.48 220 47 722 Xenon 5.90 3448 18 28 *These density values are estimated from the known density of homologous fluorocarbons. ## The solubility/density ratio value of 0.02 (supra) and the diffusivity of 2 × 10−5 cm2sec−1 given above were used in equation 7 for this Q-value determination.
Once the Q value has been determined the utility of an individual gas as an ultrasound contrast-enhancing agent can be analyzed by determining the life span of a collection of microbubbles composed of the gas in question at different sizes, as was done for air in Table I above. Taking the value of Q for decafluorobutane and examining the time necessary for various sized bubbles to dissolve in water, one obtains the values in Table III below by multiplying each of the time values in Table I by the Q value for decafluorobutane:TABLE III INITIAL BUBBLE DIAMETER, microns TIME, minutes 12 99 10 69 8 44 6 25 5 17 4 11 3 6.1 2 2.9 1 0.7
Notice that the time scale in Table III is minutes rather than milliseconds as was the case for air. All bubbles of decafluorobutane, even as small as 1 micron, can be injected peripherally and will not dissolve into solution during the approximately 10 seconds needed to reach the left ventricle. Similar calculations can be performed for a gas with any Q coefficient. Slightly larger bubbles will be able to pass through the lungs and yet survive long enough to permit both examination of myocardial perfusion and dynamic abdominal organ imaging. Moreover, as with many of the gases identified by this method, decafluorobutane features low toxicity at small dosages and would, therefore, offer substantial advantages as a contrast-enhancing agent in conventional ultrasound diagnosis.
Manual creation of a microbubble suspension may be accomplished by several methods. U.S. Pat. No. 4,832,941, the disclosure of which is incorporated herein by reference, refers to a method for producing a suspension of microbubbles with a diameter less than seven microns created by spraying a liquid through a quantity of gas using a three-way tap. Although techniques could vary in practice, the three-way tap is a preferred method to manually suspend a quantity of high Q coefficient gas to produce the contrast-enhancing media described herein.
The general techniques for use of a three-way tap device are well known in connection with preparation of the common Freund's adjuvant for immunizing research animals. Typically, a three-way tap is comprised of a pair of syringes, both of which are connected to a chamber. The chamber has outlet from which the suspension may be collected or infused directly.
Techniques for use of the three-way tap may differ from that described in U.S. Pat. No. 4,832,941 because different gases are being used in this procedure. For example, use of one of the high Q coefficient gases disclosed herein may be more efficient if the system is purged of ordinary air or flushed with another gas before the microbubble suspension is produced.
In a preferred embodiment of the present invention, a 40-50% Sorbitol (D-glucitol) solution is mixed with approximately 1-10% by volume of a high Q-coefficient gas with approximately 5% gas being an optimal value. Sorbitol is a commercially available compound that when mixed in an aqueous solution substantially increases the viscosity of the solution. Higher viscosity solutions, as seen in equation 3 above, extend the life of a microbubble in solution. A 40-50% Sorbitol solution is preferred to maintain as a bolus upon injection; that is as intact as possible without exceeding a tolerable injection pressure. To produce the suspension of microbubbles, a quantity of the chosen gas is collected in a syringe. In the same syringe, a volume of the Sorbitol solution may be contained. A quantity of Sorbitol solution is drawn into the other syringe so that the sum of the two volumes yields the proper percentage of gas based on the volume percentage of microbubbles desired. Using the two syringes, each featuring a very small aperture, the liquid is sprayed into the gas atmosphere approximately 25 times or as many times as is necessary to create a suspension of microbubbles whose size distribution is acceptable for the purposes described herein. This technique may be varied slightly, of course, in any manner that achieves the resulting suspension of microbubbles of the desired size in a desired concentration. Microbubble size may be checked either visually or electronically using a Coulter Counter (Coulter Electronics) by a known method, Butler, B. D., "Production of Microbubble for Use as Echo Contrast Agents," J. Clin. Ultrasound, V.14 408 (1986).EXAMPLES Example 1
An ultrasound contrast agent was prepared using decafluorobutane as the microbubble-forming gas. A solution was prepared containing:sorbitol 20.0 g NaCl 0.9 g soy bean oil 6.0 mL Tween 20 0.5 mL water q.s. 100.0 mL
A soapy, clear, yellow solution was afforded with stirring. A 10 mL aliquot of this solution was taken up in a 10 mL glass syringe. The syringe was then attached to a three-way stopcock. A second 10 mL syringe was attached to the stopcock and 1.0 cc of decafluorobutane (PCR, Inc., Gainesville, Fla.) was delivered to the empty syringe. The stopcock valve was opened to the solution-containing syringe and the liquid and gas phases mixed rapidly 20-30 times. A resulting milky-white, slightly viscous solution was obtained.Example 2
The gas emulsion obtained in Example 1 was diluted with water (1:10 to 1:1000), placed in a hemocytometer, and examined under the microscope using an oil immersion lens. The emulsion consisted of predominately 2-5 micron bubbles. The density was 50-100 million microbubbles per mL of original undiluted formulation.Example 3
The formulation of Example 1 was prepared and echocardiography performed in a canine model. A 17.5 kg mongrel dog was anesthetized.with isoflurane and monitors established to measure ECG, blood pressure, heart rate, and arterial blood gases according to the methods described by Keller, M W, Feinstein, S B, Watson, D D: Successful left ventricular opacification following peripheral venous injection of sonicated contrast agent: An experimental evaluation. Am Heart J 114:570d (1987).
The results of the safety evaluation are as follows:MAXIXUM PERCENTAGE CHANGE IN MEASURED PARAMETER WITHIN 5 MIN POST INJECTION AORTIC PRESSURE SYSTOLIC DIASTOLIC BLOOD GASES DOSE mm Hg MEAN PaO2 PaCO2 pH HEART RATE 0.5 mL +6, −14 +9, 0 +8, −6 329 58.1 7.26 +10 −19 1.0 mL +9, <2 +5, −1 +4, −4 +1, −4 2.0 mL +5, −3 +5, −1 +5, −1 0, −1 3.0 mL +6, −2 +7, 0 +4, −3 0, −3 4.0 mL +5, −1 +3, −3 +5, −3 0, −3 5.0 mL 0, −10 +1, −3 0, −4 +1, −1 7.0 mL 0, −13 0, −8 0, −9 313 28.6 7.36 0, −1
All changes were transient and returned to baseline values typically within 3-6 minutes. The above safety data demonstrate minimal changes in the measured hemodynamic parameter. All doses provided both right and left ventricular chamber opacification. The intensity increased with the increasing dose.Example 4
The above specific determinations of the suitability of a particular gas for use as an ultrasound agent can be approximated if the molecular weight of a particular gas is known, can be calculated, or can be measured. This approximation is based on the determination that there is a linear relationship between the logarithm of the Q-value and the molecular weight for a gas, thus the following guidelines can be used to estimate a Q-value:Molecular Weight Estimated Q-Value <35 <5 35-70 5-20 71-100 21-80 101-170 81-1000 171-220 1001-10,000 221-270 10,001-100,000 >270 >100,000
The following Table contains a series of gases with the relevent data on molecular weight and estimated Q-value. The higher Q-value the more promising is the particular gas. Especially promising are gases with Q-values greater than five. Additional issues, including, but not limited to, cost and toxicity, should be considered in addition to longevity of the derived microbubbles (as estimated by the Q-value) in determining the suitability of any particular gas as an ultrasound contrast agent.TABLE IV Molecular Estimated O Chemical Name Weight Value Acetone, hexafluoro 166.02 81-1000 Acetylene, isopropyl 68 5-20 Air 28.4 <5 Allene 40.06 5-20 Allene, tetrafluoro 112.03 81-1000 Argon 39.98 5-20 Borne, dimethyl, methoxy 71.19 21-80 Borne, trimethyl 55.91 5-20 Boron fluoride dihydrate 103.84 81-1000 1,2-Butadiene 54.09 5-20 1,3-Butadiene 54.09 5-20 1,3-Butadiene, 1,2,3-trichloro 157.43 81-1000 1,3-Butadiene, 2-fluoro 72.08 21-80 1,3-Butadiene, 2-methyl 68.12 5-20 1,3-Butadiene, hexafluoro 162.03 81-1000 Butadiyne 50.06 5-20 n-Butane 58.12 5-20 Butane, 1-fluoro 76.11 21-80 Butane, 2-methyl 72.15 21-80 Butane, decafluoro 238.03 10,001-100,000 1-Butene 56.11 5-20 2-Butene {cis} 56.11 5-20 2-Butene {trans} 56.11 5-20 1-Butene, 2-methyl 70.13 5-20 1-Butene, 3-methyl 70.13 5-20 2-Butene, 3-methyl 68 5-20 1-Butene, perfluoro 200.03 1001-10,000 2-Butene, perfluoro 200.03 1001-10,000 3-Butene-2-one, 4-phenyl {trans} 146.19 81-1000 1-Butene-3-yne, 2-methyl 66.1 5-20 Butyl nitrite 103.12 81-100 1-Butyne 54.09 5-20 2-Butyne 54.09 5-20 Butyne, 2-chloro-1,1,1,4,4,4-hexafluoro 199 1001-10,000 1-Butyne, 3-methyl 68.12 5-20 2-Butyne, perfluoro 162.03 81-1000 Butyraldehyde, 2-bromo 151 81-1000 Carbon dioxide 44.01 5-20 Carbonyl sulfide 60.08 5-20 Crotononitrile 67.09 5-20 Cyclobutane 56.11 5-20 Cyclobutane, methyl 70.13 5-20 Cyclobulane, octafluoro 200.03 1001-100,000 Cyclobutene, perfluoro 162.03 81-1000 Cyclopentene, 3-chloro 102.56 81-1000 Cyclopropane 42.08 5-20 Cyclopropane, 1,2-dimethyl {trans, dl} 70.13 5-20 Cyclopropane, 1,1-dimethyl 70.13 5-20 Cyclopropane, 1,2-dimethyl {cis} 70.13 5-20 Cyclopropane, 1,2-dimethyl {trans, l} 70.13 5-20 Cyclopropane, ethyl 70.13 5-20 Cyclopropane, methyl 56.11 5-20 Deuterium 4.02 <5 Diacetylene 50.08 5-20 Diaziridine, 3-ethyl-3-methyl 86.14 21-80 Diazoethane, 1,1,1-trifluoro 110.04 81-1000 Dimethyl amine 45.08 5-20 Dimethyl amine, hexafluoro 153.03 81-1000 Dimethyl disulfide, hexafluoro 202.13 1001-10,000 Dimethylethylamine 73.14 21-80 bis-(Dimethyl phosphino) amine 137.1 81-1000 2,3-Dimethyl-2-norbornano 140.23 81-1000 Dimethylamine, perfluoro 171.02 1001-10,000 Dimethyloxonium chloride 82.53 21-80 1,3-Dioxolane-2-one, 4-methyl 102.09 81-1000 Ethane 30.07 <5 Ethane, 1,1,1,2-tetrafluoro 102.03 81-1000 Ethane, 1,1,1-trifluoro 84.04 21-80 Ethane, 1,1,2,2-tetrafluoro 102.03 81-1000 Ethane, 1,1,2-trichloro-1,2,2-trifluoro 187.38 1001-10,000 Ethane, 1,1-dichloro 98 21-80 Ethane, 1,1-dichloro-1,2,2,2-tetrafluoro 170.92 1001-10,000 Ethane, 1,1-dichloro-1-fluoro 116.95 81-1000 Ethane, 1,1-difluoro 66.05 5-20 Ethane, 1,2-dichloro-1,1,2,2-tetrafluoro 170.92 1001-10,000 Ethane, 1,2-difluoro 66.05 5-20 Ethane, 1-chloro-1,1,2,2,2-pentafluoro 154.47 81-1000 Ethane, 1-chloro-1,1,2,2-tetrafluoro 136.48 81-1000 Ethane, 2-chloro,1,1-difluoro 100 21-80 Ethane, 2-chloro,1,1,1-trifluoro 118.49 81-1000 Ethane, Chloro 64.51 5-20 Ethane, chloro pentafluoro 154.47 81-1000 Ethane, dichlorotrifluoro 152 81-1000 Ethane, fluoro 48.06 5-20 Ethane,hexafluoro 138.01 81-1000 Ethane, nitro-pentafluoro 165.02 81-1000 Ethane, nitroso-pentafluoro 149.02 81-1000 Ethane, perfluoro 138.01 81-1000 Ethyl amine, perfluoro 171.02 1001-100,000 Ethyl ether 74.12 21-80 Ethyl methyl ether 60.1 5-20 Ethyl vinyl ether 72.11 21-80 Ethylene 28.05 <5 Ethylene, 1,1-dichloro 96.94 21-80 Ethylene, 1,1-dichloro-2-fluoro 114.93 81-1000 Ethylene, 1,2-dichloro-1,2-difluoro 132.92 81-1000 Ethylene, 1,2-difluoro 64 5-20 Ethylene, 1-chloro-1,2,2-trifluoro 116.47 81-1000 Ethylene, chloro trifluoro 116.47 81-1000 Ethylene, dichloro difluoro 132.92 81-1000 Ethylene, tetrafluoro 100.02 21-80 Fulvene 78.11 21-80 Helium 4 <5 1,5-Heptadiyne 92.14 21-80 Hydrogen (H2) 2.02 <5 Isobutane 58.12 5-20 Isobutane, 1,2-epoxy-3-chloro 106.55 81-1000 Isobutylene 56.11 5-20 Isoprene 68.12 5-20 Krypton 83.8 21-80 Methane 16.04 <5 Methane sulfonyl chloride, trifluoro 168.52 81-1000 Methane sulfonyl fluoride, trifluoro 152.06 81-1000 Methane, (pentafluorothio)trifluoro 196.06 1001-10,000 Methane, bromo difluoro nitroso 159.92 81-1000 Methane, bromo fluoro 112.93 81-1000 Methane, bromo-chloro-fluoro 147.37 81-1000 Methane, bromo-trifluoro 148.91 81-1000 Methane, chloro difluoro nitro 131.47 81-1000 Methane, chloro dinitro 140.48 81-1000 Methane, chloro fluoro 68.48 5-20 Methane, chloro trifluoro 104.46 81-1000 Methane, chloro-difluoro 86.47 21-80 Methane, dibromo difluoro 209.82 1001-10,000 Methane, dichloro difluoro 120.91 81-1000 Methane, dichloro-fluoro 102.92 81-1000 Methane, difluoro 52.02 5-20 Methane, difluoro-iodo 177.92 1001-10,000 Methane, disilano 76.25 21-80 Methane, fluoro 34.03 <5 Methane, iodo- 141.94 81-1000 Methane, iodo-trifluoro 195.91 1001-10,000 Methane, nitro-trifluoro 115.01 81-1000 Methane, nitroso-trifluoro 99.01 21-80 Methane, tetrafluoro 88 21-80 Methane, trichlorofluoro 137.37 81-1000 Methane, trifluoro 70.01 5-20 Methanesulfenylchloride, trifluoro 136.52 81-1000 2-Methyl butane 72.15 21-80 Methyl ether 46.07 5-20 Methyl isopropyl ether 74.12 21-80 Methyl nitrite 61.04 5-20 Methyl sulfide 62.13 5-20 Methyl vinyl ether 58.08 5-20 Neon 20.18 <5 Neopentane 72.15 21-80 Nitrogen (N2) 28.01 <5 Nitrous oxide 44.01 5-20 1,2,3-Nonadecane tricarboxylic acid, 2- 500.72 >100,000 .....hydroxytrimethylester 1-Nonene-3-yne 122.21 81-1000 Oxygen (O2) 32 <5 1,4-Pentadiene 68.12 5-20 n-Pentane 72.15 21-80 Pentane, perfluoro 288.04 >100,000 2-Pentanone, 4-amino-4-methyl 115.18 81-1000 1-Pentene 70.13 5-20 2-Pentene {cis} 70.13 5-20 2-Pentene {trans} 70.13 5-20 1-Pentene, 3-bromo 149.03 81-1000 1-Pentene, perfluoro 250.04 10,001-100,000 Phthalic acid, tetrachloro 303.91 >100,000 Piperidine, 2,3,6-trimethyl 127.23 81-1000 Propane 44.1 5-20 Propane, 1,1,1,2,2,3-hexafluoro 152.04 81-1000 Propane, 1,2-epoxy 58.08 5-20 Propane, 2,2-difluoro 80.08 21-80 Propane, 2-amino 59.11 5-20 Propane, 2-chloro 78.54 21-80 Propane, heptafluoro-1-nitro 215.03 1001-10,000 Propane, heptafluoro-1-nitroso 199.03 1001-10,000 Propane, perfluoro 188.02 1001-10,000 Propene 42.08 5-20 Propyl,1,1,1,2,3,3-hexafluoro-2,3-dichloro 221 10,001-100,000 Propylene, 1-chloro 76.53 21-80 Propylene, 1-chloro-{trans} 76.53 5-20 Propylene, 2-chloro 76.53 5-20 Propylene, 3-fluoro 60.07 5-20 Propylene, perfluoro 150.02 81-1000 Propyne 40.06 5-20 Propyne, 3,3,3-trifluoro 94.04 21-80 Styrene, 3-fluoro 122.14 81-1000 Sulfur hexafluoride 146.05 81-1000 Sulfur (di),decafluoro(S2F10) 298 >100,000 Toluene, 2,4-diamino 122.17 81-1000 Trifluoroacetonitrile 95.02 21-80 Trifluoromethyl peroxide 170.01 81-1000 Trifluoromethyl sulfide 170.07 81-1000 Tungsten hexafluoride 298 >100,000 Vinyl acetylene 52.08 5-20 Vinyl ether 70 5-20 Xenon 131.29 81-1000 Example 5
The relationship between a calculated Q-value for a given gas and the persistence of microbubbles of that gas was studied to determine what Q-value would be a lower limit for utility as an ultrasound contrast agent. For these experiments, a 190×100 mm Pyrex™ (No. 3140) evaporation dish was filled with approximately 2000 mL of water at 37° C. Five mL of a 20% sorbitol solution was taken up in a 10 mL syringe connected to a three way stopcock. A 10 mL syringe, containing 2 cubic centimeters of the subject gas (or low boiling liquid, as pertinent) was attached to the syringe containing the sorbitol solution. The sorbitol and gas or liquid are rapidly mixed 25-times to create a suspension of microbubbles or dispersed liquid and then rapidly added to the water. The microbubbles of this method are generally about 100 microns in size, and if composed of air would have a calculated persistence of 31 sec (0.5 min). Ultrasound scans before, during and after the addition were made with a Hewlett-Packard Model Sonos 500 ultrasound scanner operating at 5 MHz. The time during which the microbubbles could be observed was recorded. The results are contained in Table V below. The experimental Q-values were obtained by dividing the measured persistence of a given gas by the measured persistence for air.TABLE V RELATIONSHIP BETWEEN Q-VALUE FOR A GAS AND THE PERSISTENCE OF MICROBUBBLES PERSISTENCE Q-VALUE (Experimental GAS (Calculated) Q-Value) Diethyl ether 0.1 0.1 min (0.2) Air 1 0.6 min (1.0) Butane 5 1.5 min (2.6) Helium 5 2.0 min (3.5) Propane 30 3.2 min (6.0) Pentane 58 20.6 min (36) Dodecafluoropentane 207,437 >5760 min (>10,105)
These experiments indicate an excellent agreement between the calculated Q-value and the experimentally determined values. Based on these data, gases with Q-values calculated to be greater than five should be potentially useful as contrast agents for ultrasound imaging.Example 6
The relationship of the state of matter of a given chemical entity with a high Q-coefficient and its utility as an ultrasound contrast coefficient and its utility as an ultrasound contrast agent was tested by comparing the efficiency of perfluoropentane and perfluorohexane to act as an ultrasound contrast agent. Perfluoropentane (dodecafluoropentane) has a calculated Q-coefficient of 207,437 and a boiling point under standard pressure conditions of 29.5 degrees Centigrade. Perfluorohexane (PCR, INc., Gainsville, Fla.) has a calculated Q-coefficient of 1,659,496 and a boiling point under standard pressure conditions of 59-60 degrees C. Therefore, at 37 degrees C., the body temperature of man, perfluoropentane is a gas while perfluorohexane is a liquid.
Aqueous dispersions of perfluoropentane and perfluorohexane (2% w/v) were formed at 4 degrees C. by vigorous homogenization. A plastic beaker, containing approximately 1000 mL of water at 37 degrees C., was prepared to simulate human blood and was ultrasonically-scanned, as indicated in Example 5 above, before and after the addition of samples of each of the above dispersions.
Less than 1.0 mL of the perfluoropentane dispersion, when mixed with the simulated blood, produced an extremely bright ultrasound signal which persisted for at least 30 minutes. A 1:10,000 dilution was still detectable.
In contrast, a 1.0 mL sample of the perfluorohexane dispersion was undetectable by ultrasound scanning under the same conditions, as was even a 10 mL sample (1:100 dilution).
The conclusion to be drawn is that both a high Q-coefficient and a gaseous state at the body temperature of the organism being scanned is necessary for a substance to be effective as an ultrasound contrast agent according to the method that is the subject matter of this invention.
Although the invention has been described in some respects with reference to specified preferred embodiments thereof, variations and modifications will become apparent to those skilled in the art. It is, therefore, the intention that the following claims not be given a restrictive interpretation but should be viewed to encompass variations and modifications that are derived from the inventive subject matter disclosed. In this regard the invention allows those skilled in the art to determine the suitability of various chemicals as ultrasound contrast agents where density, solubility and molar volume data are available.
1. A method of resonance imaging using ultrasonic energy transmitted by an ultrasonic source to an object or body to be imaged, comprising:
- introducing into said object or body a contrast agent comprising microbubbles containing a gas selected from perfluoropropane, and perfluoropentane, or a mixture thereof; and
- ultrasonically imaging at least a portion of said object or body.
2. A method according to claim 1 in which the gas is perfluoropropane.
3. A method according to claim 1 in which the gas is perfluoropentane.
4. A method according to claim 1 in which the microbubbles comprise free gas microbubbles.
5. A method according to claim 1 in which the resonance imaging is medical resonance imaging.
6. A method of medical ultrasound resonance imaging using ultrasonic energy transmitted by an ultrasonic source to a body to be imaged, comprising:
- introducing into said body an ultrasound contrast agent comprising microbubbles containing a gas selected from perfluoropropane, and perfluoropentane, or a mixture thereof; and
- ultrasonically imaging at least a portion of said body.
7. A method according to claim 6 in which the gas is perfluoropropane.
8. A method according to claim 6 in which the gas is perfluoropentane.
9. A method according to claim 6 in which the microbubbles comprise free gas microbubbles.
10. A method according to claim 6 in which a portion or structure of a body is imaged.
|October 1971
|Morehouse et al.
|March 1972
|Jungermann et al.
|July 6, 1976
|Spitzer et al.
|May 31, 1977
|May 5, 1981
|July 7, 1981
|Tickner et al.
|April 17, 1984
|Rasor et al.
|August 21, 1984
|Hilmann et al.
|August 6, 1985
|Cook et al.
|October 1, 1985
|Ryan et al.
|February 25, 1986
|April 14, 1987
|Rasor et al.
|July 21, 1987
|Rasor et al.
|August 4, 1987
|January 12, 1988
|February 16, 1988
|August 30, 1988
|October 4, 1988
|May 23, 1989
|Berwing et al.
|July 4, 1989
|Widdler et al.
|August 22, 1989
|Davis et al.
|September 12, 1989
|January 23, 1990
|Schweighardt et al.
|February 13, 1990
|Ryan et al.
|May 22, 1990
|September 18, 1990
|Cerny et al.
|January 15, 1991
|Charpiot et al.
|January 22, 1991
|February 19, 1991
|January 7, 1992
|January 14, 1992
|February 18, 1992
|April 28, 1992
|Levene et al.
|May 19, 1992
|Wolf et al.
|June 23, 1992
|August 11, 1992
|Erbel et al.
|August 25, 1992
|Rasor et al.
|September 15, 1992
|Glajch et al.
|September 22, 1992
|October 13, 1992
|December 15, 1992
|Kaufman et al.
|April 27, 1993
|May 11, 1993
|July 27, 1993
|November 9, 1993
|Meinert et al.
|December 21, 1993
|Schneider et al.
|January 25, 1994
|February 8, 1994
|September 6, 1994
|Roth et al.
|September 27, 1994
|Kaufman et al.
|October 11, 1994
|Klaveness et al.
|February 28, 1995
|April 18, 1995
|Brandenburger et al.
|April 25, 1995
|May 9, 1995
|Schneider et al.
|June 20, 1995
|Reinhardt et al.
|August 29, 1995
|Schneider et al.
|January 30, 1996
|Cohen et al.
|March 26, 1996
|Rossling et al.
|April 16, 1996
|Grinstaff et al.
|April 30, 1996
|Grinstaff et al.
|June 25, 1996
|Klaveness et al.
|July 2, 1996
|Schneider et al.
|July 16, 1996
|Lohrmann et al.
|August 20, 1996
|September 3, 1996
|Lambert et al.
|September 17, 1996
|Yan et al.
|September 24, 1996
|September 24, 1996
|September 24, 1996
|September 24, 1996
|September 24, 1996
|Klaveness et al.
|September 24, 1996
|Klaveness et al.
|October 1, 1996
|October 8, 1996
|October 22, 1996
|Klaveness et al.
|October 22, 1996
|Schneider et al.
|October 22, 1996
|November 5, 1996
|November 12, 1996
|November 26, 1996
|November 26, 1996
|Schneider et al.
|January 28, 1997
|Schneider et al.
|February 4, 1997
|Beller et al.
|February 25, 1997
|Schutt et al.
|March 4, 1997
|Lambert et al.
|March 18, 1997
|Bernstein et al.
|March 25, 1997
|Klaveness et al.
|April 8, 1997
|Schroder et al.
|May 6, 1997
|Schutt et al.
|June 10, 1997
|Klaveness et al.
|June 17, 1997
|Schutt et al.
|July 1, 1997
|Schneider et al.
|August 19, 1997
|Scheider et al.
|January 13, 1998
|December 5, 2000
|August 1989
|October 1991
|April 1988
|March 1925
|0 324 938
|July 1989
|April 1990
|41 27 442
|February 1993
|0 077 752
|April 1983
|0 231 091
|August 1987
|0 245 019
|November 1987
|0 307 087
|March 1989
|0 327 490
|August 1989
|0 357 163
|March 1990
|0 359 246
|March 1990
|0 454 044
|October 1991
|0 458 745
|November 1991
|0 467 031
|January 1992
|0 494 615
|July 1992
|0 502 814
|September 1992
|0 554 213
|August 1993
|October 1966
|March 1988
|August 1990
|April 1991
|March 1992
|November 1980
|August 1989
|November 1989
|March 1990
|July 1990
|July 1990
|July 1991
|September 1991
|October 1991
|December 1991
|February 1992
|April 1992
|May 1992
|July 1992
|September 1992
|September 1992
|October 1992
|October 1992
|October 1992
|October 1992
|December 1992
|December 1992
|December 1992
|January 1993
|January 1993
|February 1993
|April 1993
|April 1993
|May 1993
|September 1993
|March 1994
|May 1994
|May 1994
|September 1994
|September 1994
|September 1994
|September 1994
|December 1994
|January 1995
- "'Freon' Fluorocarbons: Properties and Applications" in Dupont Technical Bulletin G-1 (Dupont de Nemours and Company, Wilmintong, DE)pp. 1-10 (1987).*
- Registry Copyrights 2001 ACS, RN 76-10-7 (2001).*
- Grant & Hackh's Chemical Dictionary, pp. 246 (1987).*
- Violante, et al., Particle-Stabilized Bubbles For Enhanced Organ Ultrasound Imaging, Investigative Radiology 26, Suppl. 1:S194-99 (1991).
- Vygantas, et al., Octafluorocyclobutane and Other Gases For Vitreous Replacement, Arch. Opthalmology 90:235-36 (1973).
- Wheatley, et al., Contrast Agents for Diagnostic Ultrasound: Development and Evaluation of Polymer-Coated Microbubbles, Biomaterial 11:713-717 (1990).
- Whitacre, B-Scan Ultrasonography of Eyes Containing Intravitreal Gas, Am. J. Ophthalmol.: Series 3, 112(3):272-77 (1991).
- White, et al., Bibliography of Biomedical Ultrasound, Ultrasound in Med. and Biol. 13(9):571-86 (1987).
- Widder, et al., Microbubbles as a Contrast Agent for Neurosonography and Ultrasound-Guided Catheter Manipulation: In Vitro Studies, AJR 147:347-52 (1986).
- Zarif, et al., Synergistic Stabilization of Perfluorocarbon-Pluronic F-68 Emulsion by Perfluoroalylated Polyhydroxlated Surfactants, JAOCS 66(10), 8 pages (1989).
- Ziskin, et al., Contrast Agents for Diagnostic Ultrasound, Investigative Radiology 7(6):500-05 (1972).
- Merck, The Merck Index, 11th Edition, Merck & Co., Inc. publishers, pp. 297 and 1643 (1989).
- Miller, et al., Physicochemical Approaches to the Mode of Action of General Anesthetics, Anesthesiology 36(4):339-51 (1972).
- Nomura, et al., US Contrast Enhancement of Hepatic Tumor with Helium Gas Microbubbles: A Preliminary Report, Jpn. J. Med. Ultrasonics 18(5):444-45 (1991) (includes English translation).
- Ohta, et al., Effect of the Contrast Agent and the Agitation Method on the Size, Number and Stability of Microbubbles: A Basic Experiment for the Myocardial Contrast Study, Jpn. J. Med. Ultrasonics 18(4):318-25 (1991).
- Ophir, Contrast Agents in Diagnostic Ultrasound, Ultrasound in Med. and Biol. 15:319-33 (1989).
- Fluorocarbon Numbering, Research Chemicals Catalog, pp. 206-212 (1994).
- Robertson, et al., Beyond Partition Coefficients—Individual Properties of Infused Inert Gases Influencing Their Elimination From the Lung, Prog. Resp. Res. 21:177-81 (1986).
- Rosecan, et al., Therapeutic Ultrasound in the Treatment of Retinal Detachment: Clinical Observations and Light and Electron Microsocpy, Retina 5(2):115-22 (1985).
- Sakata, et al., Acute Toxicity of Fluorocarbon-22: Toxic Symptoms, Lethal Concentration and its Fate in Rabbit and Mouse, Toxicology and Applied Pharmacology 59:64-70 (1981).
- Sass, et al., Gas Embolism Due to Intravenous FC 80 Liquid Fluorocarbon, J. Appl. Phys. 40(5):745-51 (1976).
- Schlief, Ultrasound Contrast Agents, Current Opinion in Radiology 3(2):198-07 (1991).
- Schneider, et al., Polymeric Microballoons as Ultrasound Contrast Agents: Physical and Ultrasonic Properties Compared with Sonicated Albumin, Investigative Radiology 27(2):134-39 (1992).
- Schubert, et al., Microemulsifying Fluorinated Oils with Mixtures of Fluorinated and Hydrogenated Surfactants, Colloids and Surfaces: Physicochemical and Engineering Aspects 84:97-106 (1994).
- Serratrice, et al., Co-Solubilisation De Fluorocarbures Et D'Eau En Presence De Nouveaux Tensioactifs Non Ioniques Fluores, J. Chim. Phys. 87:1969-80 (1990).
- Simaan, et al., Hemodyn Effects of Aerosol Propellants: I. Cardiac Depression in the Dog, Toxicology 5:127-38 (1995).
- Swanson, et al., Enhancement Agents for Ultrasound: Fundamentals, Pharmaceuticals in Medical Imaging MacMillan Publishing, Ch. 22, pp. 682-87 (1990).
- Szonyi, et al., Syntheses De Tensioactifs F-Alkyles Non Ioniques Monodisperses, J. Fluorine Chem. 36:195-209 (1987).
- Unger, et al., Nitrogen-Filled Liposomes as a Vascular Us Contrast Agent: Preliminary Evaluation, Radiology 185(2):453-56 (1992).
- Varescon, et al., An Easy, Convenient Way of Describing the Stability of Fluorocarbon Emulsions, J. de Chimie Physique 86(10):2111-16 (1989).
- Handa, et al., Phospholipid Monolayers at the Triolein-Saline Interface: Production of Microemulsion Particles and Conversion of Monolayers to Bilayers, Biochemistry 29:2884-90 (1990).
- Hilpert, Contrast Agents in Diagnostic Ultrasound, Diagnostic Ultrasound (Mosby Year Book) 1:30-42 (1991).
- Jacobs, Intraocular Gas Measurement Using A-Scan Ultrasound, Current Eye Research, 5(8):575-78 (1986).
- Kabalnov, et al., Solubility of Fluorocarbons in Water as a Key Parameter Determining Fluorocarbon Emulsion Stability, J. Fluorine Chem. 50(3):271-84 (1990).
- Keller, et al., The Behavior of Sonicated Albumin Microbubbles within the Microcirculation: A Basis For Their Use During Myocardial Contrast Echocardiography, Circulation Research, University of Virginia, School of Medicine, 65(2):458-67 (1989).
- Keller, et al., Successful Left Ventricular Opacification Following Peripheral Venou Injection of Sonicated Contrast Agent: An Experimental Evaluation, Am. Heart Journal 115(4):570-75 (1987).
- Keller, et al., Ultrasound Backscatter Characteristics of Sonicated Echo Contrast Agents, Circulation, Abstracts Of The 58th Scientific Sessions 72(4):III-427 (1985).
- Levene, et al., Characterization of Albunex, J. Acoust. Soc. Am. 67:S69-70 (1990).
- Lincoff, et al., Intravitreal Expansion of Perfluorocarbon Bubbles, Arch. Ophthalmol. 98:1646 (1980).
- Lincoff, et al., Intravitreal Longevity of Three Perfluorocarbon Gases, Arch. Opthalmol. 98:1610-11 (1980).
- Lincoff, et al., Perfluoro-N-Butane: A Gas For a Maximum Duration Retinal Tamponade, Arch. Ophthalmol. 101:460-62 (1983).
- Lincoff, et al., Perfluorocarbon Gases in the Treatment of Retinal Detachment, Opthalmology 90(5):546-51 (1983).
- Long, et al., Experiments with Radiopaque Perfluorocarbon Emulsions for Selective Opacification of Organs and Total Body Angiography, Investigative Radiology 15:242-47 (1980).
- Marshall, Encyclodedie Des Gaz, Encyclopedia of Gas (1976).
- Mattrey, et al., Gas Emulsions as Ultrasound Contrast Agents Preliminary Results in Rabbits and Dogs, Investigative Radiology 29:S139-S141. Jun. Supplement (1994).
- Mattrey, et al., Liver and Spleen Specific Ultrasound Contrast Material. Investigative Radiology 17(4):S28, Abstract 110 (1982).
- Mattrey, et al., Perfluorcytlbromide: A Liver/Spleen-Specific and Tumor-Imaging Ultrasound Contrast Material, Radiology 145:759-62 (1982).
- Meltzer, et al., Transmission of Ultrasonic Contrast Through the Lungs, Ultrasound in Med. & Biol. 7(4):377-84 (1981).
- Meltzer, et al., Why Do the Lungs Clear Ultrasonic Contrast?, Ultrasound in Med. and Biol. 7(6):263-69 (1980).
- Barnhart, et al., Characteristics of Albunex: Air-Filled Microspheres for Echocardiography Contrast Enhancement, Investigative Radiology, vol. 25, Suppl. 1.
- Bleeker, et al., On the Application of Ultrasonic Contrast Agents for Blood Flowmetry and Assessment of Cardiac Perfusion, J. Ultrasound Med. 9(8):461-71 (1990).
- Bleeker, et al., Ultrasonic Characterization of Albunex, a New Contrast Agent, J. Acoust. Soc. Am. 87:1792-97 (1990).
- Bommer, et al., Report of the American Society of Echocardiography: Contrast Echocardiography, pp. 1-10 (1984).
- Carlton, Fluorocarbon Toxicity: Aerosol Deaths and Anaesthetic Reactions, Ann. of Clinical and Laboratory Science 6(5), pp. 411-14 (1978).
- Clark, et al., Can Fluorocarbon Emulsions be Used as Artificial Blood?, Triangle 11(4):115-22 (1972).
- Coden, et al., Intraocular Pressure Response After Pneumatic Retinopexy, Opthalmalic Surgery 19(9):667-69 (1988).
- Davis, et al., Echogenicity Caused by Stable Microbubbles in a Protein-Lipid Emulsion, J. Clin. Ultrasound 9(5):249-52 (1981).
- DeJong, et al., Absorption and Scatter of Encapsulated Gas Filled Microspheres: Theoretical Considerations and Some Measurements, Ultrasonics 30:95-103 (1992).
- DeJong, et al., Principles and Recent Developments in Ultrasound Contrast Agents, Ultrasonics 29:324-30 (1991).
- DuPont, "Freon" Fluorocarbons, Properties and Applications, Abstract, pp. 1-11.
- DuPont, Properties and Applications of the "Freon" Fluorocarbons, Technical Bulletin, pp. 1-11.
- Epstein, et al., On the Stability of Gas Bubbles in Liquid-Gas Solutions, J. Chem. Phys. 18:1505-09 (1950).
- Ericksen, et al., Methylcellulose, Handbook of Pharmaceutical Excipients, American Pharmaceutical Association & Pharmaceutical Society of Great Britain, pp. 181-183 (1986).
- Feinsten, Myocardial Perfusion Imaging: Contrast Echocardiography Today and Tomorrow, JACC 8(1):251-53 (1986).
- Feinsten, et al., Microcardial Contrast Echocardiography: Examination of Infracoronary Injections. Microbubble Diameters and Video Intensity Decay, Am. J. Phys. Imaging 1:12-18 (1986).
- Feinsten, et al., Safety and Efficacy of a New Transpulmonary Ultrasound Contrast Agent: Initial Multicenter Clinical Results, JACC 16:316-24 (1990).
- Fobbe, et al., Color-Coded Duplex Sonography and Ultrasound Contrast Media—Demonstration of Peripheral Renal Perfusion Defects in an Animal Experiment, Fortschr. Rontgenstr. 154(3):242-45 (1991).
- Gardner, et al., A Survey of Intraocular Gas Use in North America, Arch. Ophthalmol. 106:1188-89 (1988).
Type: Grant
Filed: Sep 28, 2000
Date of Patent: Sep 16, 2003
Assignee: Amersham Health A/S (Oslo)
Inventor: Steven C. Quay (Pacific Palisades, CA)
Primary Examiner: Russell Travers
Assistant Examiner: Shahnam Sharareh
Attorney, Agent or Law Firm: Townsend and Townsend and Crew LLP
Application Number: 09/670,894
International Classification: A61K/9133; A61B/800;


text:
Acushnet, Massachusetts
|This article is a stub. Help us to expand it by contributing your knowledge. For county and town page guidelines, visit U.S. County Page Content Suggestions.
Acushnet is a town in Massachusetts. It was formed in 1860 and was previously called Fairhaven. It can be found in Bristol county and is a part of the Southern registry of deed district. For more information, contact the county at 122 Main St., Acushnet 02743. On the attached map, Acushnet is shown as 19 in Bristol county.
For information about the state of Massachusetts see Massachusetts Family History Research.


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Graduate Certificate Community College
This new certificate was recommended by the Academic Senate on December 6, 2001 and approved by the President on January 9, 2002.
The community college graduate certificate is designed to prepare graduate students to work in community college settings as teaching faculty or counselors. Courses offered in this program provide students with an overview of the community college and its role in the American higher education system. Students will gain insights and experiences in the classroom and in fieldwork that will strengthen their knowledge and skills in working with community college students, faculty, and staff. The certificate program consists of 18 units; 9 units are from the master's degree program and must be approved by the student's master's degree program graduate advisor; and 9 units are specific to the study of college students, the community college, and fieldwork. All students will be required to:
1. Be enrolled in a master's degree program or have an earned master's degree in a discipline leading to teaching or counseling in post-secondary education settings.
2. Complete 9 units of coursework in Educational Psychology: Introduction to the Community College (EDP 552), Students in U.S. Higher Education (EDP548), and a fieldwork class that is counseling or teaching focused (EDP 644B).
3. Complete an additional 9 units approved by their master's degree program graduate advisor for consideration to fulfill the 18 units required for the certificate. These courses may include pedagogy, learning theory, instructional management, and/or teaching methodology courses in the student's major area of study, or any other courses in the discipline deemed appropriate by the master's degree program graduate advisor.
EFFECTIVE: Fall 2002
Code: 1-3001
College: 50
Career: GR