1. An X-ray diagnostic apparatus comprising: processing circuitry configured to obtain, with respect to a plurality of groups of time-course fluoroscopic images that are obtained by acquiring a subject injected with a contrast media, in at least two directions, each of which intersect, first transition information that indicates transition of a signal intensity of the contrast media in a proximal region to which the contrast media flows earlier than a region of interest, and reconstruct three-dimensional image data in the region of interest such that a value that is obtained by projecting a voxel value approximates a value of a corresponding pixel in each of the groups of time-course fluoroscopic images, the voxel value being represented by second transition information that is obtained by deforming the first transition information with a factor that is related to the contrast media; and a display configured to display the fluoroscopic image with a blood vessel image based on the three-dimensional image data.