Dynamic contrast-enhanced magnetic resonance imaging parameters independent of baseline T10 values.

A baseline T(10) value is typically needed for dynamic contrast-enhanced (DCE-) MRI studies. However, an assumed baseline T(10) has to be used when T(10) measurements for patients are not available. In this work, we systematically investigate the dependence on T(10) of the commonly used DCE-MRI parameters (K(trans), k(ep), v(e) and IAUC) as well as several newly defined parameters [the normalized ratios (NRs) of k(ep), K(trans) and v(e), which are measures of relative changes in these parameters between two time points] for a spoiled gradient-echo pulse sequence using simulations and in vivo studies. Effects of various factors on the T(10) dependence, such as the true T(10) value, flip angle and the potential changes in T(10) due to treatment, were also assessed using simulations. We found that DCE-MRI parameters k(ep) and the NR of k(ep) are largely independent of T(10), especially when larger flip angles are used (e.g., 30-40 degrees). Their estimations therefore do not require any knowledge of T(10). The NRs of K(trans), v(e) and IAUC also exhibit independence to T(10), but only when T(10) remains constant between pre- and posttreatment. The estimation of parameters themselves (K(trans), v(e) and IAUC) is highly dependent on the T(10) value.