Novel Gadolinium-Free Ultrasmall Nanostructured Positive Contrast for Magnetic Resonance Angiography and Imaging
Rodrigo Ken Kawassaki, Mariana Romano, Mayara Klimuk Uchiyama, Roberta Mansini Cardoso, Maurı́cio S. Baptista, Sandra Helena Poliselli Farsky, Khallil Taverna Chaim, Robson R. Guimarães, Koiti Araki
Abstract
High Resolution Image Download MS PowerPoint Slide Nanostructured contrast agents are promising alternatives to Gd 3+ -based chelates in magnetic resonance (MR) imaging techniques. A novel ultrasmall paramagnetic nanoparticle (UPN) was strategically designed to maximize the number of exposed paramagnetic sites and r 1 while minimizing r 2, by decorating 3 nm titanium dioxide nanoparticles with suitable amounts of iron oxide. Its relaxometric parameters are comparable to those of gadoteric acid (GA) in agar phantoms, and the r 2 / r 1 ratio of 1.38 at 3 T is close to the ideal unitary value. The strong and prolonged contrast enhancement of UPN before renal excretion was confirmed by T 1 -weighted MR images of Wistar rats after intravenous bolus injection. Those results associated with good biocompatibility indicate its high potential as an alternative blood-pool contrast agent to the GA gold standard for MR angiography, especially for patients with severe renal impairment.