Tiny 3-D ultrasound probe guides catheter procedures

August 28, 2008
3-D Transducer. Credit: Ned Light, Duke University

An ultrasound probe small enough to ride along at the tip of a catheter can provide physicians with clearer real-time images of soft tissue without the risks associated with conventional x-ray catheter guidance.

Duke University biomedical engineers designed and fabricated the novel ultrasound probe which is powerful enough to provide detailed, 3-D images. The new device works like an insect's compound eye, blending images from 108 miniature transducers working together.

Catheter-based procedures involve snaking instruments through blood vessels to perform various tasks, such as clearing arteries or placing stents, usually with the guidance of x-ray images.

In a series of proof-of-principle experiments in a water tank using simulated vessels, the engineers used the new ultrasound probe to guide two specific procedures: the placement of a filter within a vessel and the placement of a synthetic "patch" for aortic aneurysms. The scientists plan to begin tests of the new system in animals within the year.

"There are no technological barriers left to be overcome," said Stephen W. Smith, director of the Duke University Ultrasound Transducer Group and senior member of the research team that published the results of its latest experiments online in the journal IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. It is the cover article for the September issue.

"While we have shown that the new probe can work for two types of procedures, we believe that results will be more far-reaching," Smith said. "There are many catheter-based interventional procedures where 3-D ultrasound guidance could be used, including heart valve replacements and placement of coils in the brain to prevent stroke. Wherever a catheter can go, the probe can go."

Currently, when maneuvering a catheter through a vessel, physicians rely on x-ray images taken from outside the body and displayed on a monitor to manipulate their instruments. Often, a contrast agent is injected into the bloodstream to highlight the vessel.

"While the images obtained this way are good, some patients experience adverse reactions to the contrast agent," said research engineer Edward Light, first author of the paper and designer of the new probe. "Also, the images gained this way are fleeting. The 3-D ultrasound guidance does not use x-ray radiation or contrast agents, and the images are real-time and continuous."

Another benefit is portability, which is an important issue for patients who are too sick to be transported, since x-rays need to be taken in specially equipped rooms, Light said. The 3-D ultrasound machine is on wheels and can be moved easily to a patient's room.

Advances in ultrasound technology have made these latest experiments possible, the researchers said, by generating detailed, 3-D moving images in real-time. The Duke laboratory has a long track record of modifying traditional 2-D ultrasound – like that used to image babies in utero – into the more advanced 3-D scans. After inventing the technique in 1991, the team also has shown its utility in developing specialized catheters and endoscopes for real-time imaging of blood vessels in the heart and brain.

After testing many iterations of the design of the probe, also known as a transducer, the engineers came up with a novel approach – lining the front rim of the catheter sheath with 108 miniature transducers.

"These tiny transducers work together to create one large transducer, working much like the compound eyes of insects," Light explained.

In the first experiment, the new probe successfully guided the placement of a filter in a simulated vena cava, the large vein that carries deoxygenated blood from the lower extremities to the back to heart. Patients with clots in their legs – known as deep vein thrombosis – who cannot get clot-busting drugs often receive these filters to prevent the clots dislodging and traveling to the heart and lungs.

The second experiment involved the placement of abdominal aorta aneurysm stent grafts, which are large synthetic "tubes" used to patch weakened areas of the aorta that are at risk of bursting.

"I believe we have shown that 3-D ultrasound clearly works in a wide variety of interventional procedures," Smith said. "We envision a time in the not-too-distant future when this technology becomes standard equipment in various catheter kits."

Source: Duke University

Explore further: New dental imaging method uses squid ink to fish for gum disease

Related Stories

New dental imaging method uses squid ink to fish for gum disease

September 7, 2017
Squid ink might be a great ingredient to make black pasta, but it could also one day make getting checked for gum disease at the dentist less tedious and even painless. By combining squid ink with light and ultrasound, a ...

Study shows incisionless surgery with MR-HIFU effective in destroying painful bone tumors

August 24, 2017
Doctors from the Sheikh Zayed Institute for Pediatric Surgical Innovation at Children's National Health System have completed a clinical trial that demonstrates how osteoid osteoma, a benign but painful bone tumor that commonly ...

Tiny bubbles offer sound solution for drug delivery

June 25, 2017
Your brain is armored. It lives in a box made of bones with a security system of vessels. These vessels protect the brain and central nervous system from harmful chemicals circulating in the blood. Yet this protection system—known ...

Brain ultrasound improves mood

May 16, 2013
Non-invasive brain stimulation techniques aimed at mental and neurological conditions include transcranial magnetic stimulation (TMS) for depression, and transcranial direct current (electrical) stimulation (tDCS), shown ...

New head scanning ultrasound technology could save soldier lives

June 20, 2016
Soldiers' lives could be saved or improved by new technology which enables medics to scan for bleeding in the brain using ultrasound.

Anaesthesia with surgical precision

November 17, 2015
Ultrasound technology will soon be helping doctors to anaesthetise patients more accurately. And the technology is being developed in Trondheim, Norway.

Recommended for you

Lactation hormone also helps a mother's brain

September 26, 2017
The same hormone that stimulates milk production for lactation, also acts in the brain to help establish the nurturing link between mother and baby, University of Otago researchers have revealed for the first time.

Image ordering often based on factors other than patient need: study

September 25, 2017
Do you really need that MRI?

Bone marrow concentrate improves joint transplants

September 25, 2017
Biologic joint restoration using donor tissue instead of traditional metal and plastic may be an option for active patients with joint defects. Although recovery from a biologic joint repair is typically longer than traditional ...

Researchers describe mechanism that underlies age-associated bone loss

September 22, 2017
A major health problem in older people is age-associated osteoporosis—the thinning of bone and the loss of bone density that increases the risk of fractures. Often this is accompanied by an increase in fat cells in the ...

Researchers develop treatment to reduce rate of cleft palate relapse complication

September 22, 2017
Young people with cleft palate may one day face fewer painful surgeries and spend less time undergoing uncomfortable orthodontic treatments thanks to a new therapy developed by researchers from the UCLA School of Dentistry. ...

Exosomes are the missing link to insulin resistance in diabetes

September 21, 2017
Chronic tissue inflammation resulting from obesity is an underlying cause of insulin resistance and type 2 diabetes. But the mechanism by which this occurs has remained cloaked, until now.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.