Medical image processing apparatus, reconstruction method and X-ray diagnostic apparatus based on a change of a density of a contrast agent over time

A medical image processing apparatus comprises processing circuitry configured to acquire a first blood vessel image based on X-rays that are irradiated from a first direction and a second blood vessel image based on X-rays that are irradiated from a second direction; determine a corresponding point on the second blood vessel image, which is a point corresponding to a subject point on the first blood vessel image, by using an epipolar line corresponding to the subject point and blood-flow information based on a change of a density of a contrast agent over time at the subject point; and reconstruct a three-dimensional blood vessel image by using information about the subject point and the corresponding point.