The setting method of the region of interest is indicated. Slices in which the tendon graft and bone tunnel walls were most linear in the longitudinal direction in an oblique sagittal plane were used. On the femoral side, the inner wall of the bone tunnel, 5 mm anterior and posterior to the center of the tendon graft on Blumensaat’s line and parallel to this line, was regarded as the bone tunnel wall, which was manually enclosed as a linear region with a width of 2 mm. On the tibial side, the inner wall of the bone tunnel, 5 mm anterior and posterior to the center of the tendon graft at the bone tunnel opening on the joint surface side parallel to the joint surface, was regarded as the bone tunnel wall, which was enclosed in the same way as the femur side. The measured signal intensity was divided by the signal intensity of air, 2.0 cm anterior to the tibial tuberosity, in order to obtain the signal-to-noise ratio as normalization of signal intensity