PVP‐coated Gd‐grafted nanodiamonds as a novel and potentially safer contrast agent for in vivo MRI
A. M. Panich, Moti Salti, Ofer Prager, Evyatar Swissa, Yu. V. Kulvelis, Elena B. Yudina, Alexander E. Aleksenskii, S. D. Goren, A. Ya. Vul’, Alexander I. Shames
Abstract
Purpose Testing the potential use of saline suspension of polyvinylpyrrolidone (PVP)‐coated gadolinium(Gd)‐grafted detonation nanodiamonds (DND) as a novel contrast agent in MRI. Methods Stable saline suspensions of highly purified de‐agglomerated Gd‐grafted DND particles coated by a PVP protective shell were prepared. T 1 and T 2 proton relaxivities of the suspensions with varying gadolinium concentration were measured at 8 Tesla. A series of ex vivo (phantom) and in vivo dynamic scans were obtained in 3 Tesla MRI using PVP‐coated Gd‐grafted DND and gadoterate meglumin in equal concentrations of gadolinium, and then T 1 ‐weighted hyperintensity was compared. Results The proton relaxivities of PVP‐coated Gd‐grafted DND were found to be r 1 = 15.9 ± 0.8 s −1 mM −1 and r 2 = 262 ± 15 s −1 mM −1 , respectively, which are somewhat less than those for uncoated Gd‐grafted DND but still high enough. Ex vivo MRI evaluation of PVP‐coated Gd‐grafted DND results with a dose‐dependent T 1 ‐weighted hyperintensity with a significant advantage over the same for gadoterate meglumin. The same was found when the 2 contrast agents were tested in vivo. Conclusion The novel MRI contrast agent — saline suspensions of PVP‐coated Gd‐grafted DND — provides significantly higher signal intensities than the common tracer gadoterate meglumin, therefore increasing its potential for a safer use in clinics.