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 imaging signal 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: identify, based on the atlas and for each of the at least one substructure, a corresponding portion of image voxels in said image; provide a computed quantification of the corresponding portion of image voxels for each of the at least one substructure of said tissue region by performing spatial filtering on said image; and search said database 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.