High Magnetic Field MRI Technology Provides Comprehensive Analysis of Strokes

A new, novel way to categorize the severity of a stroke, help in diagnosis, and assesse potential treatments has been demonstrated by US researchers.

“Stroke affects millions of adults and children worldwide,” said Dr. Sam Grant, researcher and associate professor of chemical and biomedical engineering at the Florida State University-based National High Magnetic Field Laboratory (FAMU-FSU; MagLab; Tallahassee, FL, USA) and the FSU College of Engineering. “This research offers a new technique for the chemical analysis of metabolites during stroke and a means of evaluating dynamic changes in cell processes and size in living tissue.”

The research was described in two articles, one published October 9, 2014, in the journal Nature Communications, and the other published September 10, 2014, in the Journal of Cerebral Blood Flow and Metabolism.

The new technique is a way of narrowly applying energy to the metabolites of a specimen exposed to a very high magnetic field. By selectively “exciting” these metabolites and studying their distribution and confinement in brain tissue, the research team can investigate the metabolic microenvironment and tell whether cells were shrinking or expanding, a vital application for determining the severity of stroke, according to Dr. Grant.

These data could help clinicians to better treat patients. “Strokes cause an interruption of blood and oxygen to flow to the brain,” explained Jens Rosenberg, another MagLab researcher and one of Grant’s coauthors. “Through this research, we can see how neurons and other neural cells respond to the disruption of blood flow after stroke and use that information to better understand the full impacts of stroke.”

The MagLab’s flagship 900 MHz ultra-wide bore nuclear magnetic resonance (NMR) magnet system was a vital element to the research. Utilizing this powerful magnet, the researchers, which included scientists from the Champaulimaud Center (Lisbon, Portugal) and the Weizmann Institute of Science (Rehovot, Israel), were able to capture localized chemical signatures of metabolites from 125-microliter volumes within the brain with high sensitivity and fidelity in six seconds.

Typical magnetic resonance imaging (MRI) scans performed at hospitals or physician offices measure around 1.5–3 Tesla (the unit of magnetic field strength), while the 900 MHz measures an enormous 21.1 Tesla, providing at least seven times the sensitivity. “This very high field, coupled with the RF [radiofrequency] pulse sequence design by our collaborators and homebuilt RF probes offer a unique noninvasive way of evaluating stroke evolution and potential treatments,” Dr. Rosenberg said.

Moreover, the investigators envision exciting possibilities to use this technique to additionally study devastating disorders. “By evaluating spectral regions previously undetectable, we hope to fingerprint certain diseases, like ischemic stroke, so that we can identify new characteristics that are specific to pathological conditions at the metabolic level in vivo,” Dr. Grant said. “There is a lot of work to be done to identify these dynamic changes and decide when and how our treatments can be most effective.”

Additional studies on metabolites using this technique could also be used for analysis of neurological disorders such as dementia, schizophrenia, Lou Gehrig’s, Parkinson’s, Alzheimer’s and Huntington’s diseases.

Related Links:
Florida State University-based National High Magnetic Field Laboratory
Champaulimaud Center 
Weizmann Institute of Science