scholarly journals Polymeric Gd-DOTA amphiphiles form spherical and fibril-shaped nanoparticle MRI contrast agents

2016 ◽  
Vol 7 (7) ◽  
pp. 4230-4236 ◽  
Author(s):  
Lyndsay M. Randolph ◽  
Clare L. M. LeGuyader ◽  
Michael E. Hahn ◽  
Christopher M. Andolina ◽  
Joseph P. Patterson ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Amphiphilic Block Copolymers ◽  
Mri Contrast Agent ◽  
Mri Contrast

A Gd3+-coordinated polymerizable analogue of the MRI contrast agent Gd-DOTA was used to prepare amphiphilic block copolymers, with hydrophilic blocks composed entirely of the polymerized contrast agent.

scholarly journals Study on Establishing Reference Safe Concentrations of MRI Contrast Agents for Optimized Images: Paramagnetic Gd-DTPA-BMEA and Superparamagnetic Ferucarbotran

2021 ◽  
Vol 11 (3) ◽  
pp. 1165
Author(s):  
Wen-Tien Hsiao ◽  
Yi-Hong Chou ◽  
Jhong-Wei Tu ◽  
Ai-Yih Wang ◽  
Lu-Han Lai
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
In Vitro Experiments ◽  
Mri Contrast ◽  
In Vivo Experiments ◽  
Contrast Agent Injection

The purpose of this study is to establish the minimal injection doses of magnetic resonance imaging (MRI) contrast agents that can achieve optimized images while improving the safety of injectable MRI drugs. Gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) and ferucarbotran, commonly used in clinical practice, were selected and evaluated with in vitro and in vivo experiments. MRI was acquired using T1-weighted (T1W) and T2-weighted (T2W) sequences, and the results were quantitatively analyzed. For in vitro experiments, results showed that T1W and T2W images were optimal when Gd-DTPA-bisamide (2-oxoethyl) (Gd-DTPA-BMEA) and ferucarbotran were diluted to a volume percentage of 0.6% and 0.05%; all comparisons were significant differences in grayscale statistics using one-way analysis of variance (ANOVA). For in vivo experiments, the contrast agent with optimal concentration percentages determined from in vitro experiments were injected into mice with an injection volume of 100 μL, and the images of brain, heart, liver, and mesentery before and after injection were compared. The statistical results showed that the p values of both T1W and T2W were less than 0.001, which were statistically significant. Under safety considerations for MRI contrast agent injection, optimized MRI images could still be obtained after reducing the injection concentration, which can provide a reference for the safety concentrations of MRI contrast agent injection in the future.

scholarly journals Iron(iii) chelated paramagnetic polymeric nanoparticle formulation as a next-generation T1-weighted MRI contrast agent

RSC Advances ◽  
2021 ◽  
Vol 11 (51) ◽  
pp. 32216-32226
Author(s):  
Ramesh Marasini ◽  
Sagar Rayamajhi ◽  
Anthony Moreno-Sanchez ◽  
Santosh Aryal
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Next Generation ◽  
Mri Contrast ◽  
Polymeric Nanoparticle ◽  
Nanoparticle Formulation

In pursuit of safer alternatives to Gd-based MRI contrast agents due to its toxicity and organ deposition, herein, we developed a safer and efficient clinically relevant iron(iii) chelated polymeric nanoparticle as a T1-weighted MRI contrast agent.

scholarly journals A Photocleavable Contrast Agent for Light-Responsive MRI

2020 ◽  
Vol 13 (10) ◽  
pp. 296
Author(s):  
Friederike Reeßing ◽  
Sèvrin E. M. Huijsse ◽  
Rudi A. J. O. Dierckx ◽  
Ben L. Feringa ◽  
Ronald J.H. Borra ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Whole Body ◽  
Spatiotemporal Resolution ◽  
Mri Contrast ◽  
High Relaxivity ◽  
Vis Spectroscopy ◽  
Clinical Mri

Thanks to its innocuousness and high spatiotemporal resolution, light is used in several established and emerging applications in biomedicine. Among them is the modulation of magnetic resonance imaging (MRI) contrast agents’ relaxivity with the aim to increase the sensitivity, selectivity and amount of functional information obtained from this outstanding whole-body medical imaging technique. This approach requires the development of molecular contrast agents that show high relaxivity and strongly pronounced photo-responsiveness. To this end, we report here the design and synthesis of a light-activated MRI contrast agent, together with its evaluation using UV–vis spectroscopy, Fast Field Cycling (FFC) relaxometry and relaxometric measurements on clinical MRI scanners. The high relaxivity of the reported agent changes substantially upon irradiation with light, showing a 17% decrease in relaxivity at 0.23T upon irradiation with λ = 400 nm (violet) light for 60 min. On clinical MRI scanners (1.5T and 3.0T), irradiation leads to a decrease in relaxivity of 9% and 19% after 3 and 60 min, respectively. The molecular design presents an important blueprint for the development of light-activatable MRI contrast agents.

Towards advanced paramagnetic nanoassemblies of highly ordered interior nanostructures as potential MRI contrast agents

2017 ◽  
Vol 41 (7) ◽  
pp. 2735-2744 ◽  
Author(s):  
Abhishek Gupta ◽  
Liliana de Campo ◽  
Lynne J. Waddington ◽  
Robert B. Knott ◽  
Dennis Hwang ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Mri Contrast ◽  
Ordered Nanostructures

A novel paramagnetic amphiphile designed to form nanoassemblies of highly ordered nanostructures was explored as an advanced MRI contrast agent.

Nanostructured magnetic nanocomposites as MRI contrast agents

2015 ◽  
Vol 3 (11) ◽  
pp. 2241-2276 ◽  
Author(s):  
Erwin Peng ◽  
Fenghe Wang ◽  
Jun Min Xue
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Magnetic Nanoparticle ◽  
Mri Contrast Agents ◽  
Water Soluble ◽  
Mri Contrast Agent ◽  
Magnetic Nanocomposites ◽  
Functional Coating ◽  
Mri Contrast ◽  
Nanoparticle Assemblies

The development of water-soluble nanostructured magnetic nanocomposites based on hydrophobic magnetic nanoparticle assemblies using an organic functional coating for MRI contrast agent applications was discussed.

scholarly journals Digital Simulation Assessments of the Sensitivity of Quantitative MRI for Detection of an Iron Oxide Nanoparticle Brain MRI Contrast Agent

2021 ◽  
Author(s):  
Joong Kim ◽  
Wen-Tung Wang ◽  
Andrew Knutsen ◽  
David Brody
Keyword(s):  
Iron Oxide ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Digital Simulation ◽  
Brain Mri ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Simulation Approach ◽  
Mri Contrast ◽  
Mr Relaxation

Abstract There have been substantial efforts to develop targeted exogenous MRI contrast agents to assess specific brain pathologies. In parallel with other efforts, it is important to assess the sensitivity of candidate MRI methods for detection of contrast agents. Here, we propose a digital simulation approach, which includes MR relaxation (R1 and R2) mapping and image co-registration. We simulated the effects of 3 nm iron oxide nanoparticles (IONPs) as a model contrast agent. Two independent relaxation maps acquired from the brain of the same subject were co-registered. The baseline subtraction between the two relaxation maps showed good agreement, demonstrating the high reproducibility of the method. Next, the second relaxation map was digitally altered (“seeded”) to simulate additional MR relaxation values corresponding to several concentrations of 3 nm IONPs in various locations. The maps of absolute differences between the first relaxation map and the digitally altered second relaxation maps were assessed for conspicuity. Results based on living mouse and human brains scanned at 9.4 T and 3.0 T respectively both indicated reliable conspicuity for signal equivalent to 0.06 mM IONP or higher. Overall, the digital simulation approach is a useful method to improve the development of MRI contrast agents and accompanying MRI methodologies.

scholarly journals Multiwalled carbon nanotube hybrids as MRI contrast agents

2016 ◽  
Vol 7 ◽  
pp. 1086-1103 ◽  
Author(s):  
Nikodem Kuźnik ◽  
Mateusz Michał Tomczyk
Keyword(s):  
Carbon Nanotubes ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Molecular Probes ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Tissue Imaging ◽  
Multiwalled Carbon ◽  
Mri Contrast

Magnetic resonance imaging (MRI) is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs), their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories.

scholarly journals Iron oxide nanoparticles stabilized with dendritic polyglycerols as selective MRI contrast agents

Nanoscale ◽  
2014 ◽  
Vol 6 (16) ◽  
pp. 9646-9654 ◽  
Author(s):  
Daniel Nordmeyer ◽  
Patrick Stumpf ◽  
Dominic Gröger ◽  
Andreas Hofmann ◽  
Sven Enders ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Iron Oxide ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Iron Oxide Nanoparticles ◽  
Superparamagnetic Iron Oxide ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Oxide Nanoparticles ◽  
Mri Contrast

Superparamagnetic iron oxide nanoparticles with a dendritic polyglycerol (dPG) sulfate strongly bind to L- and P-selectin. Shielding of leukocytes reduces cell extravasation and binding to endothelial cells indicate inflammation specificity and thus, applicability as selective MRI contrast agent.

In Vivo Evaluation of a PAMAM-Cystamine-(Gd-DO3A) Conjugate as a Biodegradable Macromolecular MRI Contrast Agent

2007 ◽  
Vol 232 (8) ◽  
pp. 1081-1089 ◽  
Author(s):  
Rongzuo Xu ◽  
Yanli Wang ◽  
Xuli Wang ◽  
Eun-Kee Jeong ◽  
Dennis L. Parker ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Contrast Enhancement ◽  
Blood Pool ◽  
Pamam Dendrimers ◽  
Mri Contrast Agents ◽  
The Body ◽  
Mri Contrast Agent ◽  
High Toxicity ◽  
Mri Contrast

Macromolecular Gd(III) chelates are superior magnetic resonance imaging (MRI) contrast agents for blood pool and tumor imaging. However, their clinical development is limited by the safety concerns related to the slow excretion and long-term gadolinium tissue accumulation. A generation 6 PAMAM Gd(III) chelate conjugate with a cleavable disulfide spacer, PAMAM-G6-cystamine-(Gd-DO3A), was prepared as a biodegradable macromolecular MRI contrast agent with rapid excretion from the body. T1 and T2 relaxivities of the contrast agent were 11.6 and 13.3 m M−1sec−1 at 3T, respectively. Blood pool and tumor contrast enhancement of the agent were evaluated in female nude mice bearing MDA-MB-231 human breast carcinoma xenografts with a nondegradable conjugate PAMAM-G6-(Gd-DO3A) as a control. PAMAM-G6-cystamine-(Gd-DO3A) resulted in significant contrast enhancement in the blood for about 5 mins, and Gd-DO3A was released from the conjugate and rapidly excreted via renal filtration after the disulfide spacer was cleaved. The nondegradable control had much longer blood circulation and excreted more slowly from the body. PAMAM-G6-cystamine-(Gd-DO3A) also resulted in more prominent tumor contrast enhancement than the control. However, PAMAM-G6-cystamine-(Gd-DO3A) demonstrated high toxicity due to the intrinsic toxicity of PAMAM dendrimers. In conclusion, although PAMAM-G6-cystamine-(Gd-DO3A) showed some advantages compared with the nondegradable control, PAMAM dendrimers are not suitable carriers for biodegradable macromolecular MRI contrast agents, due to their high toxicity.

scholarly journals Brain Redox Imaging Using Blood—Brain Barrier-Permeable Nitroxide MRI Contrast Agent

2008 ◽  
Vol 28 (6) ◽  
pp. 1165-1174 ◽  
Author(s):  
Fuminori Hyodo ◽  
Kai-Hsiang Chuang ◽  
Artem G Goloshevsky ◽  
Agnieszka Sulima ◽  
Gary L Griffiths ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Brain Tissue ◽  
Blood Brain Barrier ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Brain Barrier ◽  
Mri Contrast ◽  
Blood Brain

Reactive oxygen species (ROS) and compromised antioxidant defense may contribute to brain disorders such as stroke, amyotrophic lateral sclerosis, etc. Nitroxides are redox-sensitive paramagnetic contrast agents and antioxidants. The ability of a blood—brain barrier (BBB)-permeable nitroxide, methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (MC-P), as a magnetic resonance-imaging (MRI) contrast agent for brain tissue redox imaging was tested. MC-P relaxation in rodent brain was quantified by MRI using a fast Look-Locker T1-mapping sequence. In the cerebral cortex and thalamus, the MRI signal intensity increased up to 50% after MC-P injection, but increased only by 2.7% when a BBB-impermeable nitroxide, 3CxP (3-carboxy-2,2,5,5,5-tetramethylpyrrolidine-1-oxyl) was used. The maximum concentrations in the thalamus and cerebral cortex after MC-P injection were calculated to be 1.9±0.35 and 3.0±0.50 mmol/L, respectively. These values were consistent with the ex vivo data of brain tissue and blood concentration obtained by electron paramagnetic resonance (EPR) spectroscopy. Also, reduction rates of MC-P were significantly decreased after reperfusion following transient MCAO (middle cerebral artery occlusion), a condition associated with changes in redox status resulting from oxidative damage. These results show the use of BBB-permeable nitroxides as MRI contrast agents and antioxidants to evaluate the role of ROS in neurologic diseases.

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