1. A medical image processing apparatus comprising: a storing unit configured to store first 3D image data corresponding to a first period and second 3D image data corresponding to a second period, the first and second periods defining a period therebetween in which a condition of a subject is changed; a 3D subtracting unit configured to subtract the first 3D image data from the second 3D image data to generate 3D subtraction image data; a pseudo 3D image data generating unit configured to generate pseudo 3D image data on the basis of the 3D subtraction image data; and a displaying unit configured to display the pseudo 3D image data.