The medical imaging diagnosis apparatus includes: a region-of-interest setting unit configured to acquire an image of an examination target region in the body of a subject, and thus to set up, on the image, a region of interest, in which change in concentration of a contrast medium is observed a calculator configured to calculate an average of CT values each representing the concentration of the contrast medium in the region of interest an approximation unit configured to find an approximation for the region of interest on the basis of multiple CT values calculated by the calculator for the region of interest and a comparison unit configured to compare a coefficient of the approximation with a value representing a setup condition beforehand stored, and to detect the timing of a definitive scan on the basis of the approximation which agrees with the setup condition within a predetermined range.
