WebZine
2019. 8
What's New
Carnegie Mellon researchers have developed a novel method to use ultrasound for guiding light through tissue for noninvasive endoscopic imaging of deep organs and tissue without surgery or invasive procedures.
One day, scopes may no longer need to be inserted into the body, such as down the throat or under the skin, to reach the stomach, brain, or any other organs for examination.
Maysam Chamanzar, assistant professor of electrical and computer engineering, and Matteo Giuseppe Scopelliti, an ECE Ph.D. student, have introduced a novel technique that uses ultrasound to noninvasively take optical images through a turbid medium such as biological tissue to image body’s organs. This new method has the potential to eliminate the need for invasive visual exams using endoscopic cameras.
Endoscopic imaging, or using cameras inserted directly inside the body’s organs to investigate symptoms, is an invasive procedure used to examine and diagnose symptoms of 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. Chamanzar’s new technique provides a completely non-surgical and noninvasive alternative.
The lab’s paper, published in Light: Science and Applications, a journal published by Springer Nature, shows that they can use ultrasound to create a virtual “lens” within the body, rather than implanting a physical lens. By using ultrasonic wave patterns, the researchers can effectively “focus” light within the tissue, which allows them to take images never before accessible through noninvasive means.
Biological tissue is able to block most light, especially light in the visible range of the optical spectrum. Therefore, 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 turbid media, such as 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,” says Chamanzar.
Multi-material additive manufacturing of patient-specific shaped heart valves. Elastomeric printing enables mechanical matching with the host biological tissue.
Credit: Fergal Coulter / ETH Zurich
Scientists at ETH Zurich and the South African company Strait Access Technologies are using 3-D printing to produce custom-made artificial heart valves from silicone. This could help meet an aging population's growing demand for replacement heart valves.
The human heart has four chambers, each equipped with a valve to ensure blood flow in one direction only. If any of the heart valves are leaking, narrowed or distended (or even ruptured), the blood runs back into the atria or ventricles, putting the entire heart under severe strain. In the worst case, this can lead to arrhythmia or even heart failure.
Depending on the severity of the defect, artificial heart valves can be inserted to remedy the problem. Over the next few decades, demand for this type of surgery is likely to soar in many parts of the world due to the aging population, lack of physical exercise and poor diet. It is estimated that around 850,000 people will require artificial heart valves in 2050.
Researchers working at ETH Zurich and the South African company SAT have therefore been looking for an alternative to the replacement heart valves currently in use. And with some success: they have developed an artificial heart valve made of silicone, which is created in several steps using 3-D printers. The scientists have reported on their work in an article in the latest issue of the scientific journal "Matter."
The new model has several advantages over conventional heart valves: the silicone heart valve can be tailored more precisely to the patient, as the researchers first determine the individual shape and size of the leaky heart valve using computer tomography or magnetic resonance imaging. This makes it possible to print a heart valve that fits the patient's heart chamber perfectly. The researchers use the images to create a digital model and a computer simulation to calculate in advance the forces acting on the implant and its potential deformation. The material used is also compatible with the human body, while the blood flow through the artificial heart valve is as good as with conventional replacement valves.