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Posted: Apr 11, 2011
New class of nanoscale contrasting agents to bring color to the black-and-white world of MRI
(Nanowerk News) A University of Houston engineering researcher is trying to bring color to the black-and-white world of magnetic resonance imaging to make MRIs easier to read.
MRI is a medical imaging technique used in radiology that provides detailed maps of internal structures. But MRIs can be difficult to interpret because they are in black and white and sometimes in poor focus.
Li Sun, an associate professor of mechanical engineering in UH's Cullen College of Engineering, is working on developing a new class of contrasting agents by using iron nanostructures to provide color to MRI images for the first time.
Sun recently received a three-year, $300,000 grant from the National Science Foundation for his MRI research. Original funding came from a seed grant from the Alliance for Nanohealth. Project collaborators include Dong Liu, an assistant professor of mechanical engineering at UH, and researchers at the University of Texas Health Science Center.
"Currently, MRIs are in black and white. If you use one of the existing contrasting agents, you only adjust the gray scale, which makes the bright parts of the image brighter and the dark parts darker. These new nanostructures will allow you to use different colors to identify each type of tissue," Sun said.
Most nanostructures are shaped like spheres or rods. Iron nanostructures come in less common shapes, like dumbbells or tubes, and respond only to a specific magnetic frequency.
But unusual shapes are costly to produce at the necessary nanolevel, prompting Sun to work on a more economical fabrication method for these structures. After these nanostructures are produced, they will be coated in proteins that bond only with certain types of cells, such as those that make up a ligament or a specific internal organ.
In a clinical setting, these new agents will be introduced into a patient, most likely in a liquid that will be injected. The patient will then undergo an MRI, with the machine programmed to scan at the magnetic frequencies assigned to the different nanostructures injected into the patient.
The MRI machine will assign each type of nanostructure it senses a particular color – such as red for a ligament and blue for bone. The scans will be combined into a single, color-coded image.
Sun said producing easier-to-read MRIs is not the only use for these new nanostructures. Individual cells, such as stem cells, could be tagged with the nanostrucutures and then tracked in the human body. And nanostructures that bond with cancer cells could be heated with a high-frequency magnetic field, killing the cancer cells but leaving nearby healthy cells intact, Sun said.
"This is high-risk, high-reward research," said Sun. "If we're successful, we'll not only change how much we can learn from an MRI, but impact a lot of other areas of healthcare and research."