Ultrasound-assisted imaging offers alternative to endoscopy

A new approach to using ultrasound technology may enable clinicians to noninvasively take optical images of a patient’s internal organs.

Researchers at Carnegie Mellon University developed the new technique, which has the potential to obviate the need for invasive visual exams using endoscopic cameras. This approach is commonly used through insertions into the body, such as down the throat or under the skin, to reach the stomach, brain or other organs.

As such, endoscopic imaging—using cameras inserted directly inside the body's organs to investigate symptoms—is an invasive procedure to examine deep tissue disease. Endoscopic imagers, or cameras on the end of catheter tubes or wires, are usually implanted through a medical procedure or surgery in order to reach the body's deep tissues.

But research, published by Maysam Chamanzar, Carnegie Mellon's assistant professor of electrical and computer engineering, and student Matteo Giuseppe Scopelliti, suggests that ultrasound can create a “virtual lens” within the body. By using ultrasonic wave patterns, the researchers can effectively "focus" light within the tissue, which enables them to take images never before accessible through noninvasive means.

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Research from Carnegie Mellon University’s College of Engineering will allow for easy and noninvasive imaging of the body’s organs using ultrasound and light. A noninvasive skin patch is one way the researchers’ ultrasound-based method could allow for easy imaging of the brain.

Biological tissue is able to block most light, especially light in the visible range of the optical spectrum, so current optical imaging methods cannot use light to access deep tissue from the surface. Chamanzar's lab, however, has used noninvasive ultrasound to induce more transparency to enable more penetration of light through biological tissue.

"Being able to relay images from organs such as the brain without the need to insert physical optical components will provide an important alternative to implanting invasive endoscopes in the body," says Chamanzar. "We used ultrasound waves to sculpt a virtual optical relay lens within a given target medium, which for example, can be biological tissue. Therefore, the tissue is turned into a lens that helps us capture and relay the images of deeper structures. This method can revolutionize the field of biomedical imaging."

The team’s research shows that this compression and rarefication effect can be used to sculpt a virtual lens in the target medium for optical imaging. This virtual lens can be moved around without disturbing the medium simply by reconfiguring the ultrasound waves from outside. This enables imaging different target regions, all noninvasively.

The researchers project that this new imaging technology could be applied in biomedical and clinical contexts within the next five years.

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