In vivo microscopic imaging of the bronchial mucosa using an endo-cytoscopy system

We investigated the capabilities of an endo-cytoscopy system (ECS) that enables microscopic imaging of the tracheobronchial tree during bronchoscopy, including normal bronchial epithelium, dysplastic mucosa and squamous cell carcinoma.

The newly developed ECS has a 3.2 mm diameter that can be passed through the 4.2 mm working channel of a mother endoscope for insertion of the ECS. It has a high magnification of 570× on a 17 in. video monitor. Twenty-two patients (7 squamous cell carcinoma, 11 squamous dysplasia and 4 after PDT therapies) were underwent white light, NBI light and AFI bronchoscopy. Both abnormal areas of interest and normal bronchial mucosa were stained with 0.5% methylene blue and examined with ECS at high magnification (570×). Histological examinations using haematoxylin and eosin staining were made of biopsied specimens. Analyzed ECS images were compared with the corresponding histological examinations.

In normal bronchial mucosa, ciliated columnar epithelial cells were visible. In bronchial squamous dysplasia, superficial cells with abundant cytoplasm were arranged regularly. In squamous cell carcinoma, large, polymorphic tumor cells showed increased cellular densities with irregular stratified patterns. These ECS images corresponded well with the light-microscopic examination of conventional histology.

ECS was useful for the discrimination between normal bronchial epithelial cells and dysplastic cells or malignant cells during bronchoscopy in real time. This novel technology has an excellent potential to provide in vivo diagnosis during bronchoscopic examinations.