Abstract: Disclosed herein are systems and methods that can assess whether there is an issue with tissue perfusion, which can help a clinician better predict any surgical complications that may arise. Fluorescence images of the tissue of a subject can continuously be observed until a portion of the tissue that first perfused with blood containing one or more fluorescent agents is at peak fluorescence. Any areas of the tissue from the fluorescence images that remain dark can be further observed until these areas of concern show their first sign of fluorescence. The time it takes for these areas of concern to show their first signs of fluorescence since the first onset of fluorescence in the tissue can be referred to as the relative onset fluorescence delay. If the relative onset fluorescence delay time is greater than a predetermined threshold, the clinician can alter or change the surgical plan.

Abstract: A method for fluorescence imaging includes receiving first fluorescence imaging data, receiving a user input selecting a reference region associated with the first fluorescence imaging data, determining a reference fluorescence intensity level based on the reference region, receiving second fluorescence imaging data, determining a relative fluorescence intensity level of a region associated with the second fluorescence imaging data that is relative to the reference fluorescence intensity level, and displaying an indication of the relative fluorescence intensity level.