A Magnetically-Actuated Ultrasound Capsule Endoscope (MUSCE) for Endoluminal Imaging in Tubular Environments

Abstract

Endoscopic ultrasound (EUS) has the ability to image tissue in and beyond the wall of the gastrointestinal (GI) tract, assisting in the early diagnosis of digestive diseases. However, traditional EUS based on flexible endoscopes could make the operation procedure traumatic and intolerable to patients; moreover, certain areas such as most of the small intestine are generally hard to image due to the limited accessibility. To perform endoluminal US imaging in hard-to-reach GI tract, this study proposes a novel magnetically-actuated ultrasound capsule endoscope (MUSCE). Firstly, the MUSCE consisting of a rotatory magnetic-acoustic head and a stable soft tether is designed, featuring small dimensions, low cost, and active locomotion. Next, the magnetic force-modulated torque actuation principle and the corresponding control strategy and US image reconstruction algorithm are analyzed, enabling simultaneous active motion and B-scan ultrasonic imaging. Finally, the effectiveness of the MUSCE is validated by locomotion and imaging tests. Results demonstrate that the designed MUSCE could perform active motion (maximum speed of $\sim$ 13.8 mm/s) and B-scan US imaging (resolution of $\sim$84.2 $\mu$m) in tubular environments with mitigated discomfort, providing a potential solution for clinical applications.