Our team has developed a minimally-invasive ultrasound imaging method that allows for real-time, 3D monitoring of medical procedures using a technique called “passive acoustic mapping”.
Passive acoustic mapping is a method of creating a visual representation of the inside of the body using sound waves. It involves emitting sound waves into the body and listening for the echoes that are reflected back by different tissues and structures. The time it takes for the echoes to return and the strength of the echoes can be used to create an image of the inside of the body. Passive acoustic mapping can be used to visualize various structures and organs in the body, such as the liver, kidneys, or heart. It is a non-invasive technique that does not use ionizing radiation, and it is often used to visualize fetuses during pregnancy.
Passive acoustic mapping can be enhanced by the use of contrast agents, such as microbubbles, which improve the visibility of certain tissues or structures in the body. Microbubbles are tiny gas-filled bubbles that can be injected into the bloodstream and produce a strong echo when encountered by sound waves. By using microbubbles, it is possible to create more detailed images of the inside of the body and to distinguish between tissues that might otherwise be difficult to differentiate.
Our technique has two key advantages over traditional passive acoustic mapping. First, in our setup the imaging transducer is placed in the center of the therapeutic transducer, rather than perpendicular to it, which improves imaging resolution. Second, we use a linear imaging transducer that is capable of rotating in its plane, allowing for the construction of a 3D image rather than just a 2D image.
These improvements to the technique may be the advancement needed to bring ultrasound-guided medical treatments to clinics. Ultrasound imaging is generally cheaper, faster, and more flexible than many other imaging modalities currently in use. For example, brain therapies, such as blood-brain barrier opening procedures, are often MRI-guided. However, MRI is expensive and not available in all medical facilities, and it is not suitable for all patients, such as those with certain types of metallic implants or certain medical conditions. Our ultrasound-based technique is therefore an appealing alternative.
