In an imaging system, a vascular image extending along a vascular length direction, which is obtained from multiple transverse cross-sectional images of a blood vessel imaged by inserting a probe into the blood vessel, and multiple fluoroscopic images of the blood vessel imaged while the probe is inserted into the blood vessel are collected. A first position and a second position along the vascular length direction, which are designated by a user on the displayed vascular image, are acquired. The vascular image and the fluoroscopic image indicating the first position and the second position are displayed.
