Assessment of neovascular permeability in a pancreatic tumor model using dynamic contrast-enhanced (DCE) MRI with contrast agents of different molecular weights

We evaluated the relationship of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)-derived pharmacokinetic parameters and contrast agents with different molecular weights (MW) in a pancreatic tumor mouse model.Panc02 tumors were induced in mice at the hind leg. DCE-MRI was performed using Gadolinium (Gd)-based contrast agents with different MW: Gd-DOTA (0.5 kDa), P846 (3.5 kDa), and P792 (6.47 kDa). Quantitative vascular parameters (AUC, K(trans), V(e), and V(p)) were calculated according to a modified Tofts two-compartment model. Values for all contrast groups were compared for tumor and control (muscle) tissues.Values for K(trans) and V(e) were significantly higher in tumor tissue than in muscle tissue. When comparing contrast agents, lowest absolute K(trans) values were observed using P792. The relative increase in K(trans) in tumor tissue compared with normal tissue was highest after the use of P792. In both tumor and normal tissues, K(trans) decreased with increasing molecular weight of the contrast agent used.It was demonstrated that values for the different DCE-MRI vascular (permeability) parameters are highly dependent on the contrast agent used. Due to their potential to better differentiate tumor from muscle tissue, higher molecular weight contrast agents show promise when evaluating tumors using DCE-MRI.