1. A non-invasive imaging system, comprising: an imaging scanner suitable to generate an image representing a tissue region of a subject under observation, the tissue region having at least one substructure and said image comprising a plurality of image voxels; a signal processing system in communication with said imaging scanner to receive the image from said imaging scanner; and a data storage unit in communication with said signal processing system, wherein said data storage unit is configured to store: an atlas comprising spatial information of said at least one substructure in the tissue region, and a database comprising a plurality of pre-stored medical images representing said tissue region, and wherein said signal processing system is adapted to: segment said image, for each of the at least one substructure, into a corresponding portion of image voxels in said image using the atlas; store a computed quantification of the corresponding portion of image voxels for each of the at least one substructure of said tissue region in said database, said computed quantification being calculated by performing spatial filtering on said image, said spatial filtering including said segmenting; and search said database using a computed quantification value as input to provide at least one selected medical image from the plurality of pre-stored medical images, the at least one selected medical image having a corresponding quantification that is substantially similar to said computed quantification value.