VisualSonics Inc., the leading manufacturer of high-resolution micro-ultrasound systems, was profiled in the September 2006 issue of Genetic Engineering News (www.genengnews.com).
VISUALSONICS TARGETS THE PRECLINICAL ARENA
By Carol Potera
VisualSonics, Inc., a leading developer of high-resolution, micro-ultrasound imaging systems, is the only company to market this type of technology to life science researchers worldwide. The company launched its Vevo™ micro-ultrasound platform in 2003. By 2005, VisualSonics had sold its 200th system, experienced a 145% compounded annual growth rate, reached $24 million in annualized sales, and obtained ISO 9001:2000 registration. All this good news comes from "making ultrasound for mice," says Tom Little, President and Chief Executive Officer of VisualSonics, based in Toronto, Ontario.
VisualSonics' Vevo 770 high-resolution, micro-ultrasound imaging system offers preclinical researchers a new way to view and quantify minute physiological structures and functions in vivo in real time with near microscopic resolution. Researchers are using the Vevo 770 to quantify angiogenesis, tumor growth, cardiovascular disease, and plaque formation in small animal models. "We specifically tailored ultrasound for the preclinical research market," Little says.
In general, ultrasound is the most widely installed clinical imaging modality, and most people are familiar with its ability to image pregnancies. These clinical ultrasound units operate at less than 15 megahertz and have resolution of 300 microns, which are "perfect for viewing a human pregnancy," says Little. At the University of Toronto, biophysicist Stuart Foster, Ph.D., wanted to improve ultrasound to view smaller structures, such as arteries and blood flowing through them. He tinkered with the physics of ultrasound and boosted the frequency to 85 megahertz thereby increasing the resolution to 30 microns. To commercialize his micro-ultrasound prototype, Dr. Foster founded VisualSonics in 1999, and he serves as its Chairman and Chief Scientific Officer.
Imaging Preclinical Phenotype
The Vevo's imaging capabilities complement the explosion of genomics data coming from the Human Genome Project. As scientists struggle to understand phenotypes, or how genes affect diseases and responses to treatments, micro-ultrasound imaging provides a non-invasive tool for viewing complex biological mechanisms in real-time.
Matthew Springer, M.D., a cardiology researcher at the University of California, San Francisco, injects stem cells into areas of infarct (dead tissue) in attempts to rejuvenate heart muscle in mice. Micro-ultrasound eliminates the need for invasive surgery to implant the stem cells. "He uses the Vevo to guide the needle into the wall of the beating heart to inject the stem cells," says Little. Another researcher working with AstraZeneca, who evaluates anti-plaque drugs, observes the real-time formation of plaque in the coronary arteries of mice with micro-ultrasound. Before adopting the Vevo, expensive and time-consuming MRI and histology were used. Several other companies developing drugs for heart disease "have Vevo written into their atherosclerotic protocols to image plaque in blood vessels," says Little.
Another requirement that Vevo fulfills is the “need to see the expression of genes in small animal models”, explains Little. Imaging living animals is particularly important for cardiovascular, cancer, developmental biology, and stem cell research. With Vevo technology, researchers can view the valves, chambers, walls, and plaque formation in an embryonic mouse heart. Although mice are the most common animal models for preclinical studies, Vevo also works well with zebrafish, chick embryos, and rats.
Besides tapping into imaging on the smaller scale, micro-ultrasound also allows pharma and biotech researchers to conduct longitudinal studies on the same animals over log periods. This greatly reduces the number of animals that must be sacrificed for histological or pathological examination. Observing physiological changes in the same animal in vivo in response to drug treatments or other interventions also provides more realistic physiological data.
In addition, researches weho study cancer can now grow and monitor tumor cells orthotopically, because the Vevo technology provides 3-D images of tumor growth or regression in situ. Although calipers five fair 2-D estimates pf the size of surface tumors, “they can be dramatically wrong if the tumor penetrates into the animal”, notes Little.
VisualSonics recently announced an exclusive arrangement to have MicroMarker Molecular Imaging kits manufactured by Bracco Group. This will allow the Vevo’s functionality to include anatomical, functional, and now molecular imaging.
Jonathan Linder, M.D., developed the Vevo technology, which consist of microbubbles with attached ligands that target certain molecules. Dr. Lindner, an expert in contrast-enhanced and molecular-based echocardiology who is now at the Oregon Health and Sciences University, joined VisualSonics as a Chief Molecular Advisor in February 2006. He will guide the creation of kits and protocols to use contrast agents to target myocardial perfusion, tumor perfusion, inflammation, and angiogenesis.
Micro-ultrasonic imaging with the Vevo replaces traditional methods, including mechanical calipers, histology, and pathology. Currently, VisualSonics micro-ultrasound technology has no direct competition globally. "We have indirect competition," says Little, in that scientists continue to use calipers and histology or more costly modalities, such as MRI.” Whereas a MRI unit can cost up to $2.5 million and takes minutes to hours to generate images, the Vevo costs $175,000 and provides images nearly instantaneously. The market opportunity for VisualSonics is over $2.9 billion”, says Little.