Researchers at the University of Michigan have developed an innovative sensor designed for bile duct stents that could help doctors detect blockages early, ensuring timely intervention and better patient outcomes.
Blockages in the bile duct can result in jaundice, liver damage, and severe, potentially fatal infections. Conditions such as pancreatic and liver cancers often necessitate the use of stents to maintain open bile ducts. However, these stents can become obstructed by bacterial sludge or gallstones, requiring urgent treatment involving antibiotics and stent replacement.
Currently, the monitoring of biliary stent blockages relies on blood tests, which means the problem must be advanced enough for bodily indicators to detect it. A sensor embedded within the stent could alert doctors to accumulating bacterial sludge, enabling intervention before the onset of symptoms.
“This novel stent sensor provides the opportunity to detect impending biliary stent obstructions without waiting for clinical symptoms, blood tests or imaging tests, all of which delay intervention,” said Richard Kwon, a clinical professor of internal medicine and gastroenterology at the University of Michigan Medical School and co-author of the study published in *Nature Microsystems & Nanoengineering*.
Measuring 8 millimeters in length and 1 millimeter in width, the sensor is encased in a protective, 3D-printed structure that adheres to plastic stents. During routine checkups, patients would wear a belt-like detector that emits alternating magnetic fields, inducing resonant vibrations in the sensor. Any buildup on the sensor appears as a shift in resonant frequency.
“Successfully receiving signals from a live animal marks a significant advancement in low-profile, batteryless magnetoelastic sensor technology, paving the way for new and expanded applications,” said Ramprasad Nambisan, a U-M doctoral graduate in electrical and computer engineering and lead author of the study.
One major challenge the team overcame was detecting the resonant frequency through up to 7 inches of fluid-rich abdominal tissue. With meticulous hardware design and advanced digital signal processing, the team achieved a signal-to-noise ratio of one million to one during tests.
“The high signal-to-noise ratio at a 17 cm readout distance suggests that future versions could be used at greater distances, accommodating variations in human anatomy,” added Yogesh Gianchandani, U-M professor of electrical and computer engineering and senior author of the study.
As reported by news-medical.net, the next phase of research involves adapting the sensor for use with metal stents. Over the long term, the team aims to miniaturize the sensor further, allowing for multiple sensors to be placed along the stent, each with unique resonant frequencies to enable localized detection of sludge buildup. Lower-cost electronics for the belt detector will also be developed, setting the stage for clinical trials.
The potential of magnetoelastic sensors extends beyond bile ducts, with possible applications in peripheral vascular stents, long-term coronary stents, and ureteral stents.