Remote optical stereoscopic multispectral imaging during cardiac surgery

Within the near infrared (NIR), coronary arteries show higher contrasts against the myocardium than coronary veins. Also, NIR can penetrate deeper into tissue than visible light (VIS). This opens perspectives to enhance coronary vasculature by combining VIS and NIR images. This may be useful in instances like intramyocardial course of coronary arteries, increased epicardial fat, epicardial adhesions after previous surgery, or pericarditis. Two cameras, with dual-band LED-arrays, alternately capture VIS color frames (400-780 nm) and NIR grey- scale frames (910-920 nm). Arterial NIR contrasts are distinguished from shadows and surface reflections, selectively enhanced, and back-projected in stereoscopic VIS color video. Proof of principle has been delivered on porcine and human hearts using off-line processing. We present these results and some of our work in progress.