The invention relates to an automatic pull-back trigger method for an intracoronary imaging device or system using blood clearance. Provided herein are one or more devices, systems, methods, and storage media for optical imaging medical devices, such as, but not limited to, optical coherence tomography (OCT), single-mode OCT, and / or multimode OCT devices and systems, and methods and storage media for use therewith, for triggering automatic pullback, including devices or systems for using blood clearance. Examples of applications include imaging, evaluation, and diagnosis of biological subjects, such as, but not limited to, gastrointestinal, cardiac, and / or ophthalmic applications, and are obtained via one or more optical instruments, such as, but not limited to, optical probes, catheters, capsules, and needles (e.g., biopsy needles). Techniques provided herein also improve processing and imaging efficiency, while implementing more accurate images.