A new hand-held scanner can spot minuscule changes in veins and arteries deep within human tissues, which could provide better and earlier diagnoses of conditions like cancer, cardiovascular disease and arthritis, researchers say.
The technology should be available for use in patients in three to five years, subject to further testing. It works by using laser-generated ultrasound waves to build a 3D image of changes in the body’s network of blood vessels.
Current 'PAT' scanners, as they are known, are too slow to produce high-quality images. Patients also have to remain still, a task made more difficult by older technology, which takes more than five minutes to capture an image. The new scanner works instantly in real time, making it more suitable for people who are frail or poorly.
Study co-writer, Prof Paul Beard, of University College London, said the technology can visualise the networks of tiny blood vessels that are present in almost all human tissues with greater clarity than existing medical imaging techniques. “This will allow the subtle vascular changes associated with diseases such as cancer, diabetes or arthritis to be detected,” Prof Beard told The National.
“This could enable the more accurate diagnosis and treatment of these highly prevalent diseases resulting in better patient outcomes and cost reductions to healthcare providers. Our scanner could potentially detect changes in the small blood vessels in the lower limbs of patients with peripheral arterial disease, a complication of diabetes and other diseases which affects 25 million people across the USA and Europe.”
If left untreated, the condition can lead to amputation. But by detecting vascular changes that precede irreversible tissue damage, the scanner could help reduce the risk, prompting treatment required to avoid amputation.
To assess its potential, the new scanner was used during preclinical tests on 10 patients with type-2 diabetes, rheumatoid arthritis or breast cancer, along with seven healthy volunteers.
In three patients with type-2 diabetes, the scanner was able to produce detailed 3D images of the small veins in the feet, highlighting deformities and structural changes in the vessels. It was also able to visualise the skin inflammation linked to breast cancer.
Andrew Plumb, Associate Prof of Medical Imaging at UCL and consultant radiologist at UCLH and a senior author of the study, said: “One of the complications often suffered by people with diabetes is low blood flow in the extremities, such as the feet and lower legs, due to damage to the tiny blood vessels in these areas. But until now we haven’t been able to see exactly what is happening to cause this damage or characterise how it develops.
“In one of our patients, we could see smooth, uniform vessels in the left foot and deformed, squiggly vessels in the same region of the right foot, indicative of problems that may lead to tissue damage in future. Photoacoustic imaging could give us much more detailed information to facilitate early diagnosis, as well as better understand disease progression more generally.”
“We’ve come a long way with photoacoustic imaging in recent years, but there were still barriers to using it in the clinic,” said Prof Beard.
“The breakthrough in this study is the acceleration in the time it takes to acquire images, which is between 100 and 1,000 times faster than previous scanners. This speed avoids motion-induced blurring, providing highly-detailed images of a quality that no other scanner can provide,” he added.
One key potential use for the new scanner is to assess inflammatory arthritis, which requires scanning all 20 finger joints in both hands, said Prof Beard. With the new scanner, this can be done in a few minutes – older PAT scanners take nearly an hour, which is too long for elderly, frail patients, he said.
The study was published in Nature Biomedical Engineering.