The present invention concerns a method and a system for creating an age-specific quantitative atlas for a biological object, the method comprising:- obtaining (101) a quantitative map of the biological object for each subject of a healthy subject population；- generating (105) an age-specific initial map for said biological object using a weighted mean；- spatially registering (106) each of the quantitative maps on the age-specific initial map；- repeating (107) the generating (105) and registering (106) steps iteratively until reaching a first predefined alignment threshold between all spatially registered quantitative maps；- storing (108) the new age-specific initial map obtained at the end of the iterative process of the repeating (107) step as the age-specific quantitative atlas for a biological object characterized by said specific age.
