An image processing apparatus comprising: a score acquisition management information storage unit in which a plurality of pieces of score acquisition management information are stored with respect to a plurality of parameters, respectively, each of the pieces of the score acquisition management information being information in which type information that is information that indicates a parameter type, and score acquisition information that is information used for acquiring a score that corresponds to said parameter, are associated with each other; a receiving unit configured to receive a diffusion weighted image; a parameter acquisition unit configured to acquire, for each of two or more units of processing, being a region composed of one or more adjacent pixels, that constitute the diffusion weighted image, a plurality of parameters, by using the diffusion weighted image, and acquire a plurality of parameter maps, each of which is information having, for each of the two or more units of processing, a corresponding parameter among the acquired plurality of parameters; a score acquisition information acquisition unit configured to acquire, from the score acquisition management information, score acquisition information that corresponds to the type information that indicates a parameter map type of each of the acquired plurality of parameter maps, the parameter map type of each parameter map corresponding to the parameter type of its parameter; a score acquisition unit configured to acquire, for each of the two or more units of processing, a score that corresponds to the parameter of each of the plurality of parameter maps, by using: the parameter that said parameter map has for each of the two or more units of processing; and the score acquisition information; a diagnostic image composition unit configured to total, for each of the two or more units of processing, two or more scores that have been acquired by the score acquisition unit with respect to the plurality of parameter maps, to calculate a diagnostic score of each of the two or more units of processing, and to compose at least one diagnostic image that has, for each of the two or more units of processing, a pixel value that corresponds to the diagnostic score of the unit of processing; and an output unit configured to output the diagnostic image. a score acquisition management information storage unit in which a plurality of pieces of score acquisition management information are stored with respect to a plurality of parameters, respectively, each of the pieces of the score acquisition management information being information in which type information that is information that indicates a parameter type, and score acquisition information that is information used for acquiring a score that corresponds to said parameter, are associated with each other; a receiving unit configured to receive a diffusion weighted image; a parameter acquisition unit configured to acquire, for each of two or more units of processing, being a region composed of one or more adjacent pixels, that constitute the diffusion weighted image, a plurality of parameters, by using the diffusion weighted image, and acquire a plurality of parameter maps, each of which is information having, for each of the two or more units of processing, a corresponding parameter among the acquired plurality of parameters; a score acquisition information acquisition unit configured to acquire, from the score acquisition management information, score acquisition information that corresponds to the type information that indicates a parameter map type of each of the acquired plurality of parameter maps, the parameter map type of each parameter map corresponding to the parameter type of its parameter; a score acquisition unit configured to acquire, for each of the two or more units of processing, a score that corresponds to the parameter of each of the plurality of parameter maps, by using: the parameter that said parameter map has for each of the two or more units of processing; and the score acquisition information; a diagnostic image composition unit configured to total, for each of the two or more units of processing, two or more scores that have been acquired by the score acquisition unit with respect to the plurality of parameter maps, to calculate a diagnostic score of each of the two or more units of processing, and to compose at least one diagnostic image that has, for each of the two or more units of processing, a pixel value that corresponds to the diagnostic score of the unit of processing; and an output unit configured to output the diagnostic image.