IN VIVO CONFOCAL MICROENDOSCOPY: FROM THE PROXIMAL BRONCHUS DOWN TO THE PULMONARY ACINUS

Abstract

In vivo endoscopic microscopy aims to provide the clinician with a tool to assess architecture and morphology of a living tissue in real time, with an optical resolution similar to standard histopathology. To date, available microendoscopic devices use the principle of fluorescence confocal microscopy, and thereby mainly analyse the spatial distribution of specific endogenous or exogenous fluorophores. Fluorescence microendoscopes devoted to respiratory system exploration use a bundle of optical fibres, introduced into the working channel of the bron- choscope. This miniprobe can be applied in vivo onto the bronchial inner surface or advanced into a distal bron- chiole down to the acinus, to produce in situ, in vivo microscopic imaging of the respiratory tract in real time. Fluorescence confocal microendoscopy has the capability to image the epithelial and subepithelial layers of the pro- ximal bronchial tree, as well as the more distal parts of the lungs, from the terminal bronchioles down to the alveolar ducts and sacs. Potential applications include in vivo microscopic assessment of early bronchial cancers, bronchial wall remodelling evaluation and diffuse peripheral lung disease exploration, as well as in vivo diagnosis of peripheral lung nodules. The technique has also the potential to be coupled with fluorescence molecular imaging. This chapter de- scribes the capabilities and possible limitations of confocal microendoscopy for proximal and distal lung exploration.

Keywords

• bronchoscopy
• confocal microscopy
• in vivo microimaging
• precancerous conditions
• probe-based confocal laser endomicroscopy
• pulmonary alveoli