[Infrared thoracoscopy].

Infrared thoracoscopy with indocyanine green (ICG) is a new method of evaluating lung perfusion. We succeeded in visualizing lung emphysematous lesions and intersegmental borders using infrared thoracoscopy with ICG in animals, and within clinical investigations. There are 2 methods in infrared thoracoscopy. One is the 2-wavelength method, and the other is the 1-wavelength method. The 2- wavelength method is based on ICG absorption, and the 1-wavelength method is based on ICG fluorescence. The 2-wavelength method is superior for the clarity of images. On the other hand, the 1-wavelength method is superior for the duration of staining and the dose of ICG. Commonly, the inflation and deflation line has been used to identify the intersegmental border, but lung reinflation narrows the surgical view and can lead to prolongation of operation time, particularly in the context of video-assisted thoracic surgery (VATS). Infrared thoracoscopy with ICG is based on blood flow rather than on ventilation and can thus achieve anatomical segmentectomy without lung reinflation. This article closely reviews the principle and usefulness of infrared thoracoscopy, and difference between 2- and 1- wavelength method.