Optical biopsies using in vivo imaging at the microscopic level have opened up the possibility of non-invasive tissue sampling. Probebased confocal laser endomicroscopy (pCLE) via flexible bronchoscopy is an emerging technology that may make this a reality. The confocal microscope was first patented by Minsky in 1957. It utilizes point illumination and a pinhole apparatus to block out-of-focus rays of light, enabling the generation of high-resolution images with a lateral resolution of 5 μm. Started from 1980’s, it has been used in vivo to image organs such as eye, skin and oral cavity.
With the emerging technique of fiber based confocal microscopy, it has become small enough to enter body cavities such as the gastrointestinal tract, bladder, cervix and now the lungs. In gastrointestinal endoscopy, pCLE is considered non-inferior to standard biopsy for Barrett’s esophagus and there are consensus recommendations for its use in the detection of gastrointestinal malignancies, as well as inflammatory bowel diseases . This review will describe how pCLE is performed as part of bronchoscopic evaluation, explain image interpretation and provide an update on emerging clinical indications in pulmonary diseases.