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VisualSonics is a manufacturer of real-time, in vivo, high-resolution micro-imaging systems designed specifically for preclinical research and is a wholly owned subsidiary of SonoSite, Inc.VisualSonics’ imaging technologies allow researchers at pharmaceutical and biotechnology companies, hospitals and universities to conduct research in cardiovascular, cancer, neurobiology and developmental biology areas. The micro-imaging technologies support research applications that include genetic research, phenotypic studies and drug development. VisualSonics high-frequency micro-imaging platforms combine high-resolution, real-time in vivo imaging with quantifiable data that have been published in over 850 scientific publications globally.VisualSonics is based out of Toronto, Ontario, Canada with operations in more than 30 countries. European operations are conducted out of Science Park, Amsterdam, Netherlands and Asia Pacific operations out of Singapore. Wikipedia.

Ram R.,University of Rochester | Mickelsen D.M.,University of Rochester | Theodoropoulos C.,VisualSonics | Blaxall B.C.,University of Rochester
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2011

Systolic and diastolic dysfunction of the left ventricle (LV) is a hallmark of most cardiac diseases. In vivo assessment of heart function in animal models, particularly mice, is essential to refining our understanding of cardiovascular disease processes. Ultrasound echocardiography has emerged as a powerful, noninvasive tool to serially monitor cardiac performance and map the progression of heart dysfunction in murine injury models. This review covers current applications of small animal echocardiography, as well as emerg Roth DM, Swaney JS, Dalton ND ing technologies that improve evaluation of LV function. In particular, we describe speckle-tracking imaging-based regional LV analysis, a recent advancement in murine echocardiography with proven clinical utility. This sensitive measure enables an early detection of subtle myocardial defects before global dysfunction in genetically engineered and rodent surgical injury models. Novel visualization technologies that allow in-depth phenotypic assessment of small animal models, including perfusion imaging and fetal echocardiography, are also discussed. As imaging capabilities continue to improve, murine echocardiography will remain a critical component of the investigator's armamentarium in translating animal data to enhanced clinical treatment of cardiovascular diseases. © 2011 the American Physiological Society. Source

Pysz M.A.,Stanford University | Foygel K.,Stanford University | Panje C.M.,Stanford University | Needles A.,VisualSonics | And 2 more authors.
Investigative Radiology | Year: 2011

Objectives: Contrast-enhanced ultrasound imaging is increasingly being used in the clinic for assessment of tissue vascularity. The purpose of our study was to evaluate the effect of different contrast administration parameters on the in vivo ultrasound imaging signal in tumor-bearing mice using a maximum intensity persistence (MIP) algorithm and to evaluate the reliability of in vivo MIP imaging in assessing tumor vascularity. The potential of in vivo MIP imaging for monitoring tumor vascularity during antiangiogenic cancer treatment was further evaluated. Materials and Methods: In intraindividual experiments, varying contrast microbubble concentrations (5 × 105 × 105 × 105 × 10 microbubbles in 100 μL saline) and contrast injection rates (0.6, 1.2, and 2.4 mL/min) in subcutaneous tumor-bearing mice were applied and their effects on in vivo contrast-enhanced ultrasound MIP imaging plateau values were obtained using a dedicated small animal ultrasound imaging system (40 MHz). Reliability of MIP ultrasound imaging was tested following 2 injections of the same microbubble concentration (5 × 10 microbubbles at 1.2 mL/min) in the same tumors. In mice with subcutaneous human colon cancer xenografts, longitudinal contrast-enhanced ultrasound MIP imaging plateau values (baseline and at 48 hours) were compared between mice with and without antiangiogenic treatment (antivascular endothelial growth factor antibody). Ex vivo CD31 immunostaining of tumor tissue was used to correlate in vivo MIP imaging plateau values with microvessel density analysis. Results: In vivo MIP imaging plateau values correlated significantly (P = 0.001) with contrast microbubble doses. At 3 different injection rates of 0.6, 1.2, and 2.4 mL/min, MIP imaging plateau values did not change significantly (P = 0.61). Following 2 injections with the same microbubble dose and injection rate, MIP imaging plateau values were obtained with high reliability with an intraclass correlation coefficient of 0.82 (95% confidence interval: 0.64, 0.94). In addition, in vivo MIP imaging plateau values significantly correlated (P = 0.01; R = 0.77) with ex vivo microvessel density analysis. Tumor volumes in treated and nontreated mice did not change significantly (P = 0.22) within 48 hours. In contrast, the change of in vivo MIP imaging plateau values from baseline to 48 hours was significantly different (P = 0.01) in treated versus nontreated mice. Conclusions: Contrast-enhanced ultrasound MIP imaging allows reliable assessment of tumor vascularity and monitoring of antiangiogenic cancer therapy in vivo, provided that a constant microbubble dose is administered. Copyright © 2011 by Lippincott Williams & Wilkins. Source

VisualSonics | Date: 2010-04-30

Photoacoustic imaging systems and methods that allow for the creation of three-dimensional (3D) images of a subject are described herein. The systems include one or more optical fibers attached to an ultrasound transducer. Ultrasonic waves are generated by laser light emitted from the optical fiber(s) and detected by the ultrasound transducer. 3D images are acquired by ultrasound signals from a series of adjacent scan planes or frames that are then stacked together to create 3D volume data.

In one aspect, matching layers for an ultrasonic transducer stack having a matching layer comprising a matrix material loaded with a plurality of micron-sized and nano-sized particles. In another aspect, the matrix material is loaded with a plurality of heavy and light particles. In another aspect, an ultrasound transducer stack comprises a piezoelectric layer and at least one matching layer. In one aspect, the matching layer comprises a composite material comprising a matrix material loaded with a plurality of micron-sized and nano-sized particles. In a further aspect, the composite material can also comprise a matrix material loaded with a plurality of heavy and light particles. In a further aspect, a matching layer can also comprise cyanoacrylate.

This invention employs multiple ultrasound pulse firings of either alternating phase and/or amplitude to detect nonlinear fundamental and subharmonic signals from microbubble contrast agents within living tissue, at high frequencies (15 MHz), e.g., with a linear array transducer. It can be shown that the contrast-to-tissue ratio (CTR) decreases with increasing ultrasound frequency because of nonlinear ultrasound propagation in tissue. However, using the subharmonic signal in addition to the nonlinear fundamental harmonic component, rather than the conventional second harmonic used at lower frequencies, provides appreciable signal strength to overcome the limitations of nonlinear tissue propagation. Additionally, the method provides for the ability to switch, at some desired frequency above 20 MHz, into a purely alternating phase inversion acquisition, in combination with bandpass filtering of the subharmonic frequency band, minimizing the losses in CTR as the frequency increases. This maintains contrast sensitivity for more limited fields of view, as penetration depth will be limited at higher frequencies. Thus, within the same micro-ultrasound imaging system, many applications of microbubble detection can be achieved with a wide range of frequencies that covers both resolution and sensitivity requirements.

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