Fiber bundle shifting endomicroscopy for high-resolution imaging

Abstract

Flexible endomicroscopes commonly use coherent fiber bundles with high core densities to facilitate high-resolution <i>in vivo</i> imaging during endoscopic and minimally-invasive procedures. However, under-sampling due to the inter-core spacing limits the spatial resolution, making it difficult to resolve smaller cellular features. Here, we report a compact and rapid piezoelectric transducer (PZT) based bundle-shifting endomicroscopy system in which a super-resolution (SR) image is restored from multiple pixelation-limited images by computational means. A miniaturized PZT tube actuates the fiber bundle behind a GRIN micro-lens and a Delaunay triangulation based algorithm reconstructs an enhanced SR image. To enable real-time cellular-level imaging, imaging is performed using a line-scan confocal laser endomicroscope system with a raw frame rate of 120 fps, delivering up to 2 times spatial resolution improvement for a field of view of 350 <i>µ</i>m at a net frame rate of 30 fps. The resolution enhancement is confirmed using resolution phantoms and <i>ex vivo</i> fluorescence endomicroscopy imaging of human breast specimens is demonstrated.