Imaging short‐lived reactive oxygen species (ROS) with endogenous contrast MRI

Purpose To characterize the relaxation properties of reactive oxygen species (ROS) for the development of endogenous ROS contrast magnetic resonance imaging (MRI). Materials and Methods ROS‐producing phantoms and animal models were imaged at 9.4T MRI to obtain T1 and T2 maps. Egg white samples treated with varied concentrations of hydrogen peroxide (H2O2) were used to evaluate the effect of produced ROS in T1 and T2 for up to 4 hours. pH and temperature changes due to H2O2 treatment in egg white were also monitored. The influences from H2O2 itself and oxygen were evaluated in bovine serum albumin (BSA) solution producing no ROS. In addition, dynamic temporal changes of T1 in H2O2‐treated egg white samples were used to estimate ROS concentration over time and hence the detection sensitivity of relaxation‐based endogenous ROS MRI. The relaxivity of ROS was compared with that of Gd‐DTPA as a reference. Finally, the feasibility of in vivo ROS MRI with T1 mapping acquired using an inversion recovery sequence was demonstrated with a well‐established rotenone‐treated mouse model (n = 6). Results pH and temperature changes in treated egg white samples were insignificant (