Wireless biliary stent system with wishbone-array resonant magnetoelastic (Warm) sensor and conformal magnetic layer

Abstract

Stents are used to maintain bile duct patency after duct narrowing occurs due to various pathologies. Unfortunately, stent placement results in sludge accumulation within a variable timeframe, leading to complications such as jaundice or liver damage. This paper presents a system for wirelessly monitoring the accumulation of sludge, comprising an integrated magnetoelastic system with a sensor and biasing permanent magnet layer that conform to the meshed topology and tubular curvature of a biliary stent. The sensors have an active area of 7.5 mm x 29 mm and a mass of 9.1 mg. A 38% decrease in the resonant frequency – from 61.6 kHz to 38.2 kHz – after application of a sludge simulant totaling 20.9 mg-2.3X the mass of the sensor – was measured with the integrated system.