Multispectral Imaging and Label-Free Capsule Endoscopy for Noninvasive Detection of Digestive Tract Vessels

Diagnosis of digestive tract (DT) diseases is limited by invasive wired endoscopy and capsule endoscopy (CE) challenges, including exogenous fluorescence risks, poor WLI contrast, and limited information acquisition of narrow-band modes. This study presents label-free imaging CE to noninvasively detect DT vessels, improving diagnostic accuracy and patient safety. Multispectral imaging CE (MICE) allows conventional white-light examination with a single light source, as well as depth-specific imaging of superficial capillaries (420 nm), shallow-seated branches (540 nm), and deep, thick vessels (590 nm), improving visualization and depth differentiation of mucosal vascular morphology. Furthermore, through synergistic multispectral operation, MICE facilitates blue-light imaging (BLI: white + 420 nm), narrow-band imaging (NBI: 420 nm + 540 nm), and dual-red imaging (DRI: 540 nm + 590 nm + 630 nm), capturing multilayered, morphologically rich vascular information for the comprehensive assessment of DT diseases. Proof-of-concept evaluations under 420, 540, and 590 nm illuminations successfully captured depth-varying vascular information on porcine DT mucosa. The vessel-to-background contrast consistently improved over WLI, with gains of 2.90, 1.94, and 1.21. Furthermore, fusion visualization of multilayered vascular information was accomplished via BLI, NBI, and DRI. In addition, an integrated platform, featuring wireless power transfer (WPT) and magnetic control (MC), ensures a stable energy supply for MICE while enabling precise control over its locomotion and orientation. To our knowledge, this represents the first label-free MICE for noninvasive detection of DT vasculature, holding significant clinical implications for diagnosing DT diseases.