Imagine if you were trying to clear rubble out of a tunnel, but you could only see that tunnel from the side, instead of looking straight into it. Well, that's currently what it's like for doctors who are trying to see inside patients' blocked coronary blood vessels using ultrasound. Soon, however, a tiny catheter-based probe may give them a 3D real-time forward view from inside those vessels – or from inside the heart itself – not unlike that seen by the microscopic submarine crew in the movie Fantastic Voyage.
Developed by a team at the Georgia Institute of Technology, the device consists of a 1.5-mm-wide disc-shaped head, from which trails 13 tiny joined cables. The idea is that it will be inserted into a patient's coronary blood vessels or heart, snaking its way through while being pushed or pulled from outside the body via an integrated 430-micron-wide guide wire, all the while using the cables to transmit ultrasound imagery.
Its head is built around a single silicon chip, which is equipped with a dual-ring array of 56 ultrasound transmit elements and 48 receive elements. Much of the processing of the ultrasound data is performed onboard the chip itself, meaning that less information has to carried outside the body – this is why it requires no more than 13 cables, allowing its consolidated "umbilical cord" to stay skinny and flexible enough to easily move through blood vessels.
Additionally, its circuitry shuts off specific elements when they're not needed, minimizing its energy requirements and thus keeping its operating temperature low. That's an important consideration, for something that's going inside the body.
So far, lab tests of the prototype have yielded footage possessing what is described as a "clinically-useful" quality. Experiments on animals are planned next, with commercialization of a refined system for human use down the road. It is hoped that future versions of the device will be smaller yet, and will also be able to perform magnetic resonance imaging (MRI).
A paper on the research was recently published in the journal IEEE Xplore.
Source: Georgia Tech
