Imaging

• Ultrasound methods development to exploit microbubble contrast for characterization of hemodynamics and myocardial perfusion (Burns)

• Cardiovascular magnetic resonance imaging (MRI) research characterizing cardiac pathophysiology through oxygen-sensitive imaging in the deep veins and myocardium and through real-time acquisition methods to capture cardiac dynamics; improving noninvasive MRI strategies for mapping peripheral, neural and coronary vasculature and cardiac morphology (Wright)

• Development of integrated information systems and visualization tools covering multiple imaging modalities for cardiac disease assessment and therapy guidance (in association with the Ontario Consortium for Cardiac Imaging, a multi-institutional effort led by Sunnybrook) (Burns, Wright)

Microbubbles for ultrasound

Application of microbubble technology for ultrasound imaging of the heart

Figure 1: Encapsulated microbubbles of gas used as a new contrast agent for ultrasound. They are smaller than the red blood cells, which are seen surrounding them. Work at Sunnybrook Research Institute (SRI) has developed a new acoustic imaging method that can detect these bubbles with high sensitivity, while suppressing the appearance of surrounding tissues, thus demonstrating, noninvasively, the perfusion of tissue by blood. This method, known as pulse inversion imaging, has had a significant clinical impact.

Figure 2: An area in the muscle of the heart. Microscopic vessels are important in this area because they are critically affected by a heart attack. Pulse inversion imaging with microbubbles has produced the first real-time (moving) images of perfusion of the myocardium. These images are now available to cardiologists at Sunnybrook as well as many other centres worldwide.

Figure 3: Pulse inversion imaging is capable of exploiting another nonlinear property of tissue and in doing so, improves the quality of conventional ultrasound images of moving structures such as the valve of the heart. On the left, the structure of the heart is covered in a kind of haze, which commonly limits the utility of ultrasound examination. On the right, however, the pulse inversion image clearly shows the leaflets of the mitral valve. Pulse inversion imaging was developed by a researcher and a graduate student in Sunnybrook Research Institute’s imaging research group and licensed by Sunnybrook to the ultrasound industry in 1999.

Combined MRI and X-ray system

Development of a coronary artery imaging system using both MRI and X-ray

X-ray flat-panel digital detector design and acquisition/processing optimization for sharper, clearer coronary artery imaging at reduced X-ray dose.

Integration of X-ray flat panel into an MRI system. Located at Stanford, this system is a collaboration between Dr. John Rowlands of Sunnybrook and Drs. Fahrig and Pelc of Stanford.