A new class of cubic SPIONs as a dual-mode T1 and T2 contrast agent for MRI

• Published in: Magnetic resonance imaging Vol. 49; pp. 16 - 24
• Main Authors: Alipour, Akbar, Soran-Erdem, Zeliha, Utkur, Mustafa, Sharma, Vijay Kumar, Algin, Oktay, Saritas, Emine Ulku, Demir, Hilmi Volkan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.06.2018
• Subjects: Animals; Contrast enhancement; Contrast Media; Dual-mode MRI contrast agents; Image Enhancement - methods; Kidney - anatomy & histology; Magnetic Resonance Imaging - methods; Magnetite Nanoparticles; Models, Animal; MRI relaxivity; Rats; Rats, Sprague-Dawley; Superparamagnetic iron oxide nanoparticles; Dual-mode MRI contrast agents; Superparamagnetic iron oxide nanoparticles; MRI relaxivity; Contrast enhancement
• ISSN: 0730-725X; 1873-5894
• DOI: 10.1016/j.mri.2017.09.013

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely used as a robust negative contrast agent on conventional MRI. In this study, we (a) synthesized a new class of cubic SPIONs as a dual-mode contrast agent in MRI and (b) showed the in-vivo feasibility of these nanaoparticles as a simultaneous positive and negative contrast agent. Relaxation properties and contrast enhancement analysis of the synthesized SPIONs with two different shapes (cubic vs. spherical) and three different sizes 7nm, 11nm, and 14nm were investigated to evaluate contrast enhancement in-vitro. In-vivo MRI experiments were performed on a 3T MR scanner, where a healthy anesthetized rat was imaged before, and from 20 to 80min after intravenous injection of 1mg/kg of contrast agent. Representative transmission electron microscopy (TEM) images of the synthesized nanoparticles reveal that the particles are well dispersed in a solvent and do not aggregate. The in-vitro relaxivity and contrast enhancement analysis show that, among all six SPIONs tested, 11-nm cubic SPIONs possess optimal molar relaxivities and contrast enhancement values, which can shorten the spin-lattice and spin-spin relaxation times, simultaneously. No noticeable toxicity is observed during in-vitro cytotoxicity analysis. In-vivo T1-and T2-weighted acquisitions at 60-min post-injection of 11-nm cubic SPIONs result in 64% and 48% contrast enhancement on the T1-and T2-weighted images, respectively. By controlling the shape and size of SPIONs, we have introduced a new class of cubic SPIONs as a synergistic (dual-mode) MRI contrast agent. 11-nm cubic SPIONs with smaller size and high positive and negative contrast enhancements were selected as a promising candidate for dual-mode contrast agent. Our proof-of-concept MRI experiments on rat demonstrate the in-vivo dual-mode contrast enhancement feasibility of these nanoparticles. In this study, we synthesized a new class of cubic SPIONs as a dual-mode contrast agent in MRI. In vivo MRI experiments were performed on a 3T MR scanner, where healthy anesthetized rat was imaged before, and after intravenous injection of contrast agent. By controlling the shape and size of SPIONs, we have introduced a new class of cubic SPIONs as a synergistic MRI contrast agent. 11-nm cubic SPIONs were selected as a promising candidate for dual-mode contrast agent. [Display omitted] •11nm cubic SPIONs simultaneously enhanced both positive and negative contrast in MR images.•Various SPIONs in defined crystallinity and size were synthesized to study the magnetic characteristics of the particles.•Complementary T1- and T2-weighted in vivo MRI experiments obtained using 11nm cubic SPIONs contrast agent.