Latest simulations may improve MRI

The figure, based on a simulation by Rice University engineers, shows the gadolinium ions (blue) in the water (red and white), highlighting the inner ball water, which is the water most affected by gadolinium. Researcher models of underwater gadolinium show that there is room for improvement in compounds used as contrast agents in clinical magnetic resonance imaging. Credit: Arjun Valiya Parambathu

Gadolinium-based contrast media, the gold standard for magnetic resonance imaging (MRI) for determining patient health, is improving the model originally used to enhance oil and gas recovery. According to engineers, it can be improved.

How the team led by Dilip Astagiri and Philip Singer of George R. Braun Institute of Technology studied nuclear power Magnetic resonance Tools commonly used in the oil industry to characterize underground sediments are: Molecular dynamics simulation..

“There we tackled a lot of basic scientific questions and wondered if there were other ways we could use these simulations,” says Asthagiri.

“Around the world, about 100 million MRIs are obtained each year, about 40% of which are gadolinium-based. ContrastHowever, the method of modeling MRI responses to these agents has not changed significantly since the 1980s.

Their findings are published in the Journal of the British Royal Chemistry Society Physical Chemistry Chemical Physics..

Their paper shows how limiting the number of parameters in a simulation has the potential to improve the analysis of gadolinium-based contrast media and how effective it is in imaging for clinical diagnosis. Their goal is to create better, more customizable contrast media.

Doctors use MRI equipment to “confirm” the condition of soft tissues in the body, including the brain, by inducing a magnetic moment into the hydrogen nuclei of water molecules that are always present and aligning them along a magnetic field. The device detects bright spots as the aligned nuclei “relax” to thermal equilibrium after excitation, and the faster they relax, the brighter the contrast.

That’s where paramagnetic gadolinium-based contrast media come in. “Gadolinium ions increase sensitivity and brighten the signal by reducing the T1 relaxation time of hydrogen nuclei,” says Asthagiri. “Our ultimate goal is to help optimize and design these agents.”

Gadolinium is usually “chelated” to reduce toxicity and is surrounded by metal ions. “The body needs to chelate so that the kidneys can remove gadolinium after scanning, rather than removing gadolinium on its own,” Singer said. “But chelation also slows down the rotation of the molecule, which improves the contrast of the MRI image.”

Researchers said that “chelate” comes from the Greek word for nail. “In this case, these claws grab and stabilize the gadolinium,” he said. “We hope our model will help you design a stronger grip, which will make your model safer while maximizing its ability to increase contrast.”

They say that gadolinium chelates, which revolutionized MRI examinations when introduced in the late 1980s, have recently been controversial since it was discovered that patients with kidney damage could not eliminate all toxins. I admitted. “Since then, we’ve found that if kidney function is good, the benefits outweigh the potential risks,” Singer said.

The team is also adapting the model beyond its interaction with water. “of Biological systemBecause cells contain other components such as osmotic regulators and denaturants such as urea, we are modeling gadolinium in these different environments to build for different applications. ” Said Asthagiri.

Latest simulations may improve MRI

A simulation-based diagram by an engineer at Rice University shows a gadolinium ion (dark blue) surrounded by a chelate known as DOTA in water. Chelate is required to minimize retention of gadolinium in the body after magnetic resonance imaging scans. The green atom is carbon and the light blue is nitrogen. Credit: Arjun Valiya Parambathu

Better contrast agents based on nanoparticles

For more information:
Philip M. Singer et al, Prediction of 1H NMR Relaxation of Gd3 + -aqua Using Molecular Dynamics Simulation, Physical Chemistry Chemical Physics (2021). DOI: 10.1039 / D1CP03356E

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Rice University

Quote: The latest simulation improves the MRI (2021, September 20) obtained from on September 20, 2021. There is a possibility

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Latest simulations may improve MRI

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