I am studying for a comprehensive exam on dynamic contrast enhanced MRI (DCE-MRI) and questions have come up in my practice talks about dynamic susceptibility contrast MRI (DSC-MRI). In DCE-MRI changes in signal in an artery and the tissue are converted to contrast agent concentration vs time curves, and tracer kinetic models can be applied to those curves to compute quantitative values for Ktrans, kep, vp, ve, etc. On the other hand, when I read about DSC-MRI, which works in a similar way except using T2* weighted signal instead of T1 weighted it usually says that only relative values can be calculated and they never talk about tracer kinetic modelling. Why does it seem like DSC-MRI is incapable of providing quantitative estimates of hemodynamic parameters? Why can't tracer kinetic models be applied to DSC-MRI data? I don't need a complicated in depth answer since DSC-MRI is not the main topic for my exam, I just need a quick explanation so that I don't sound stupid when the inevitable question comparing the two methods comes up.