Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

In the context of protective artificial ventilation strategies for patients with severe lung diseases, the contribution of ventilator settings to tissue changes on the alveolar level of the lung is still a question under debate. To understand the impact of respiratory settings as well as the dynamic process of respiration, high-resolution monitoring and visualization of the dynamics of lung alveoli are essential. An instrument allowing 3D imaging of lung tissue as well as imaging of functional constituents, such as elastin fibers, in in situ experimental conditions is presented in this study using a combination of Fourier domain optical coherence tomography (FD-OCT) and fiber-guided two photon microscopy. In a comparative study, fixed lung tissue, stained with sulforhodamine B for elastin fibers, was used to illustrate the ability of fiber-guided two photon excitation and single photon excitation for the visualization of elastin fibers within the tissue. Together with the fast 3D imaging capability of OCT, a new tool is given for the monitoring of alveolar lung dynamics in future in vivo experiments.