Abstract: Aspects of the disclosure relate to the identification of when a blood vessel has been sufficiently cleared of blood so as to capture intravascular images of the vessel wall. The disclosed systems and methods allow for the identification of an initial and a final blood clearing based on the identification of edges within scanlines of a plurality of image frames. The edges of a plurality of scanlines may be analyzed to determine an average edge offset for each image frame, and the average edge offsets for a plurality of image frames may be averaged over various time-windows, so as to determine when the initial and final blood clearing events have occurred. Once a final blood clearing event has been identified, the disclosed system may automatically initiate a catheter pullback procedure, so as to capture intravascular images over a length of the vessel that has been sufficiently cleared of blood.