The present invention concerns a method (100) and a system (200) for determining a regularized estimate of a change rate of a quantitative parameter measured for a biological object of a new subject, the method comprising:- measuring (105) said quantitative parameter at a first time and at a second time within a short period of time；- determining (108) an approximative change rate r of the measured quantitative parameter；the method being characterized in that it automatically determines (109) the regularized estimate rreg from rreg=1−λr+λm whereinm is a mean value for said change rate of the quantitative parameter obtained by applying a reference data model to values of said quantitative parameters obtained by measurements of the latter for said biological object of healthy subjects, wherein for each healthy subject, values of the quantitative parameter have been obtained by making a series of said measurements over a long period of time with respect to said short period of time； andλ is computed analytically using an estimate of the variance of the values of the quantitative parameters measured for said healthy subjects.
