Intraoperative thermal artery imaging of an EC-IC bypass in beagles with infrared camera with detectable wave-length band of 7-14 μm: Possibilities as novel blood flow monitoring system

Objective: In the past, the usefulness of thermal arterial imaging during coronary bypass surgery using an infrared camera has been reported by several investigators. The goal of this study is to apply this novel imaging system for intraoperative arterial imaging, as well as to develop new utilizations for a neurosurgical procedure. Materials: We have attempted real-time imaging of anastomotic and flow status in an external carotid-internal carotid artery (EC-IC) bypass surgery using a new-generation infrared camera (IRIS IV thermographic imaging system) in beagles. No contrast medium or radiation was used to obtain the images. The detectable wave-length band of the infrared lens was 7-14 μm. After completion of bypass monitoring, an additional teflon tube was inserted into a branch of the STA to inject physiological saline of different temperatures to see the changes in cortical images. Results: Anastomotic and flow status were clearly visualized throughout the operation without local surface cooling, which had been an inevitable procedure in coronary imaging to make a pronounced temperature difference between artery and adjacent tissue. In addition, cortical flow territory was visualized after injection of either cold or warm physiologic saline into the artery from an additionally inserted teflon tube into a branch of STA via bypass artery. Conclusion: From the present experience, it is considered that infrared imaging using a detectable wave length band of 7-14 μm may be applicable to a wide variety of near surface lesions, providing a non-invasive functional angiography.