MRIs Without Metal | by Daryle Lockhart | inTech
When organs are scanned with magnetic resonance imaging (MRI), patients are usually injected with a compound known as a contrast agent before going into the scanner. The most commonly used MRI contrast agents are based on the metal gadolinium; however, these metal compounds can be harmful to young children or people with kidney problems.
Researchers from MIT and University of Nebraska have now developed a metal-free contrast agent that could be safer to use in those high-risk groups. Instead of metal, this compound contains nitroxides, which are organic molecules.
This new agent could be used to generate more informative MRI scans of tumors, because it can accumulate at a tumor site for many hours without causing harm. "This is an entirely organic, metal-free MRI contrast agent that would allow cancer researchers to start to think about how to image tumors in a dynamic way over long periods of time," says Jeremiah Johnson, the Firmenich Career Development Associate Professor of Chemistry at MIT.
MRI scans often rely on contrast agents that interact with water, influencing how the water molecules respond to a magnetic field. Contrast agents that exert a strong effect are said to have high "relaxivity," which enhances the visual contrast between the target organ and surrounding tissue.
Most MRI contrast agents are based on gadolinium, which has very high relaxivity. These agents are usually excreted by the kidneys within about half an hour, so they can't be used in people with certain types of kidney problems because the gadolinium will build up and exacerbate the kidney damage. Some agents are also considered potentially unsafe to use in babies.
Johnson says that these particles could be designed to carry drugs as well as an MRI contrast agent, which would allow for long-term imaging of a tumor to monitor whether the drug is shrinking it. He is also working with researchers at MIT's Koch Institute for Integrative Cancer Research to attach the contrast agent particles to antibodies that would help them to target specific cells for imaging and possibly drug delivery. His lab is also working on improved versions of the contrast agent which have an even higher density of nitroxide, thus improving their relaxivity and enhancing the MRI contrast even more.
Source: https://phys.org/news/2017-07-metal-free-mri-contrast-agent-safer.html
TAGS: #MRI #Metal-FreeContrastAgent @MIT #inTech @Pharmative
When organs are scanned with magnetic resonance imaging (MRI), patients are usually injected with a compound known as a contrast agent before going into the scanner. The most commonly used MRI contrast agents are based on the metal gadolinium; however, these metal compounds can be harmful to young children or people with kidney problems.
Researchers from MIT and University of Nebraska have now developed a metal-free contrast agent that could be safer to use in those high-risk groups. Instead of metal, this compound contains nitroxides, which are organic molecules.
This new agent could be used to generate more informative MRI scans of tumors, because it can accumulate at a tumor site for many hours without causing harm. "This is an entirely organic, metal-free MRI contrast agent that would allow cancer researchers to start to think about how to image tumors in a dynamic way over long periods of time," says Jeremiah Johnson, the Firmenich Career Development Associate Professor of Chemistry at MIT.
MRI scans often rely on contrast agents that interact with water, influencing how the water molecules respond to a magnetic field. Contrast agents that exert a strong effect are said to have high "relaxivity," which enhances the visual contrast between the target organ and surrounding tissue.
Most MRI contrast agents are based on gadolinium, which has very high relaxivity. These agents are usually excreted by the kidneys within about half an hour, so they can't be used in people with certain types of kidney problems because the gadolinium will build up and exacerbate the kidney damage. Some agents are also considered potentially unsafe to use in babies.
Johnson says that these particles could be designed to carry drugs as well as an MRI contrast agent, which would allow for long-term imaging of a tumor to monitor whether the drug is shrinking it. He is also working with researchers at MIT's Koch Institute for Integrative Cancer Research to attach the contrast agent particles to antibodies that would help them to target specific cells for imaging and possibly drug delivery. His lab is also working on improved versions of the contrast agent which have an even higher density of nitroxide, thus improving their relaxivity and enhancing the MRI contrast even more.
Source: https://phys.org/news/2017-07-metal-free-mri-contrast-agent-safer.html
TAGS: #MRI #Metal-FreeContrastAgent @MIT #inTech @Pharmative
Better imaging agents will lead to earlier detection of disease in a safer manner.