Figure 3.

Models of different (A) endoscope positions in the catheter and (B) catheter angles. In (A), in addition to the model of (a) the center endoscope, the endoscope was brought into contact with the (b) top, (c) bottom, and (d) sidewall of the catheter. The red dashed circle of each position is the contact point between the endoscope and catheter wall. In (B), based on (a) the center model, the 2.55 mm-length part of the catheter tip was angled by 1, 2, and 3 degrees in the bottom direction. Red lines are the centerline of the blood vessel. Red dashed lines are the centerline of the angled part of the catheter.