Method for evaluating blush in myocardial tissue

A method for tracking a blood vessel in an image, comprising the steps of:

• (a) acquiring a fluorescence image of tissue containing a blood vessel;
• (b) delimiting a segment of the blood vessel with boundaries oriented substantially perpendicular to a longitudinal direction of the blood vessel;
• (c) constructing at least one curve extending between the delimiting boundaries and located within lateral vessel walls of the blood vessel, wherein the at least one curve terminates at the delimiting boundaries substantially perpendicular to the boundaries;
• and
• (d) determining a fluorescence signal intensity in the fluorescence image along the at least one curve, with the signal intensity being representative of vessel perfusion.

A method for intraoperatively assessing blood flow in surgical flaps and identifying vascular compromise, comprising the steps of:

• defining a static region of interest (ROI) in an image of the myocardial tissue;
• detecting a fluorescence response from tissue following application of a bolus of ICG into the bloodstream;
• measuring, on one of native tissue adjacent the ROI and a surgical flap pre-operatively associated with the ROI, a first rate of change of increasing perfusion of ICG with time until a determined maximum fluorescence is reached;
• measuring, on the surgical flap post-operatively associated with the ROI, a second rate of change of increasing perfusion of ICG with time until a determined maximum fluorescence is reached;
• measuring, on one of native tissue adjacent the ROI and the surgical flap pre-operatively associated with the ROI, a first rate of change of decreasing perfusion of ICG with time after the determined maximum fluorescence is reached;
• measuring, on the surgical flap post-operatively associated with the ROI, a second rate of change of decreasing perfusion of ICG with time after the determined maximum fluorescence is reached;
• and
• determining a degree of vascular compromise at the ROI from at least one of
• a ratio between said first rate of change of increasing perfusion and said second rate of change of increasing perfusion, and
• a ratio between said first rate of change of decreasing perfusion and said second rate of change of decreasing perfusion.