An image processing apparatus includes a contrast side obtaining unit, estimating unit, a simple side obtaining unit, a core area computing unit, a synthesizing unit and a display control unit. The contrast side obtaining unit obtains a contrast area and a high CT value area around the contrast area. The estimating unit estimates a contrast area in the non-contrast data and corresponding to the obtained contrast area. The simple side obtaining unit obtains a high CT value area around the estimated contrast area. The core area computing unit computes a core area included in the high CT value area of the contrast data and the non-contrast data. The synthesizing unit aligns the contrast data with the non-contrast data and generates superimposed data by superimposing the high CT value area of the contrast data on the non-contrast data. The display control unit displays the superimposed data on a display device.
