Humanin vivofluorescence microimaging of the alveolar ducts and sacs during bronchoscopy

Abstract

The aim of the present study was to assess fibred confocal fluorescence microscopy (FCFM) as a tool for imaging the alveolar respiratory system in vivo during bronchoscopy.A 488-nm excitation wavelength FCFM device was used in 41 healthy subjects including 17 active smokers. After topical anaesthesia, the 1.4-mm miniprobe was introduced into the bronchoscope working channel and advanced distally to the alveoli. Morphometric and cellular analyses were performed on selected frames harbouring a minimal compression effect.In vivo acinar microimaging was obtained from each lung segment except for the apical and posterior segments of both upper lobes. Reproducible patterns, corresponding to the elastic framework of the axial and peripheral interstitial systems, were recorded from 192 separate acini. The mean¡SD thickness of the acinar elastic fibres was 10¡2.7 mm. Alveolar mouth diameters (mean¡SD 278¡53 mm) were normally distributed but appeared smaller in the right upper lobe and right medial basal segment. Lobular microvessels (median diameter 90 mm) were equally distributed throughout the lungs. Alveolar macrophages were not detectable in nonsmokers, whereas a specific tobacco-tar-induced fluorescence was observed in smoking subjects, providing fine details of the alveolar walls and macrophages. A strong correlation was found between the number of cigarettes smoked per day and the amount of large and mobile macrophages observed in vivo, as well as with the intensity of the macrophage alveolitis.Fibred confocal fluorescence microscopy enables accurate exploration of the peripheral lung in vivo in both smokers and nonsmokers.

A Novel Method for In Vivo Imaging of Solitary Lung Nodules Using Navigational Bronchoscopy and Confocal Laser Microendoscopy

“…e Alveoscopic image at 660 nm after topical MB administration revealing scattered large cells with areas of decreased fluorescent signal which may correspond to areas of necrosis (scale bar 20 lm using the Cholangioflex Ò ). f Histopathology analysis stained with haematoxylin and eosin shows a proliferation of undifferentiated large tumor cells different from previously described alveolar cells from normal, healthy lungs [9]. Therefore, similar to the first case, this case illustrates the added benefit of MB/660 nm evaluation for in vivo cellular imaging, in addition to the analysis of elastin network using the standard 448-nm excitation.…”

“…In previous works, limitations of pCLE have been defined including artifacts linked to compression of fragile parenchyma structures as well as difficulties in interpretation of elastin network which may vary from different individuals [9,10]. However, as the site of evaluation is specific and guided by navigational bronchoscopy, these limitations are appearing less important for SPNs compared to diffuse interstitial diseases.…”

“…To image SPNs in vivo and in real-time, we developed a technique based on pCLE of the distal lung (Alveoscopy) [9,10]. The method used r-EBUS coupled with an external sheath and virtual navigation, in which the confocal miniprobe was then introduced into the sheath in order to image the target before sampling.…”

“…Due to the probe stiffness, the 1-mm Alveoflex Ò miniprobe was used to evaluate SPNs in the lingular, middle, and lower lobes in addition to the anterior segments of the upper lobes [9,10]. Meanwhile, the 0.6-mm Cholangioflex Ò was used to image the apical and posterior segments of the upper lobes.…”

“…Probe-based confocal laser endomicroscopy (pCLE) is a new technique that can microscopically image the alveoli in vivo during standard flexible bronchoscopy [7][8][9]. A thin and flexible miniprobe called Alveoflex Ò (Mauna Kea Technologies, Paris, France) is advanced through the working channel of the flexible bronchoscope to reach the distal lung.…”