In vivo wide-area cellular imaging by side-view endomicroscopy.

In vivo imaging of small animals offers several possibilities for studying normal and disease biology, but visualizing organs with single-cell resolution is challenging. We describe rotational side-view confocal endomicroscopy, which enables cellular imaging of gastrointestinal and respiratory tracts in mice and may be extensible to imaging organ parenchyma such as cerebral cortex. We monitored cell infiltration, vascular changes and tumor progression during inflammation and tumorigenesis in colon over several months.