Imaging the brain's energy usage

January 22, 2014
Imaging the brain’s energy usage
A new way to map the brain offers promise for disease diagnosis methods that would reduce patient exposure to radioactivity. Credit: wenht/iStock/Thinkstock

A team of researchers led by Kai-Hsiang Chuang of the A*STAR Singapore Bioimaging Consortium has developed a new imaging technique to measure the rate at which the brain consumes glucose, without using radioactively labeled 'tracer' molecules.

Brain cells use glucose as an energy source. Therefore, the rate at which they take up sugar from the bloodstream and break it down into its metabolites is an important indicator of cellular function and . Glucose uptake and metabolism are typically measured using a surrogate molecule called 2-deoxyglucose (2DG), containing radioactive carbon or fluorine. When injected, this molecule is taken up by and converted into 2DG-6-phosphate (2DG6P). Positron emission tomography (PET) or autoradiography is then used to detect the radioactivity levels throughout the brain, which provides a measure of glucose usage.

The technique developed by Chuang and co-workers is sensitive enough to detect levels of 2DG and 2DG6P without first having to label them with radioactive isotopes. It relies on a relatively new imaging method called chemical exchange saturation transfer (CEST) to amplify the magnetic signal produced when 2DG and 2DG6P exchange protons with water molecules.

The researchers tested the new technique, called glucoCEST, on live animals for the first time. They injected 2DG into rats and used (NMR) to detect the CEST signal. They found that the signal changes with the concentration of 2DG and 2DG6P, and that it is reduced by the general anesthetic isoflurane, which suppresses brain activity. Their results also showed that the CEST signal is not affected by acidity levels of the blood and brain or related to changes in blood flow around the brain.

Imaging of metabolism is widely used to aid diagnosis and evaluation of cancer and neurodegenerative diseases, such as Alzheimer's. Current methods involve radioactivity so they cannot be frequently used on the same patient and are typically not used on pregnant women and children. The glucoCEST method overcomes this problem, offering a new approach to the diagnosis and prognosis of such diseases.

"This method can achieve higher resolution than PET and is far more sensitive than other NMR techniques," says Chuang. "Imaging at higher magnetic fields would improve a limiting factor of the method: lower sensitivity of detection than radioactive tracers." Employing higher magnetic fields to improve the detection sensitivity would enable the use of lower doses of 2DG.

"We are now designing experiments to evaluate the feasibility of the method in humans," Chuang adds.

Explore further: Tweaking MRI to track creatine may spot heart problems earlier, study suggests

More information: Nasrallah, F. A., Pagès, G., Kuchel, P. W., Golay, X. & Chuang, K.-H., "Imaging brain deoxyglucose uptake and metabolism by glucoCEST MRI." Journal of Cerebral Blood Flow & Metabolism 33, 1270–1278 (2013). dx.doi.org/10.1038/jcbfm.2013.79

Related Stories

Tweaking MRI to track creatine may spot heart problems earlier, study suggests

January 12, 2014
A new MRI method to map creatine at higher resolutions in the heart may help clinicians and scientists find abnormalities and disorders earlier than traditional diagnostic methods, researchers at the Perelman School of Medicine ...

Sugar makes cancer light-up in MRI scanners

July 7, 2013
A new technique for detecting cancer by imaging the consumption of sugar with magnetic resonance imaging (MRI) has been unveiled by UCL scientists. The breakthrough could provide a safer and simpler alternative to standard ...

Feed a cold -- starve a tumor

October 21, 2011
The condition tuberous sclerosis, due to mutation in one of two tumor suppressor genes, TSC1 or TSC2, causes the growth of non-malignant tumors throughout the body and skin. These tumors can be unsightly and cause serious ...

Combination of two imaging techniques allows new insights into brain function

August 26, 2013
The ability to measure brain functions non-invasively is important both for clinical diagnoses and research in Neurology and Psychology. Two main imaging techniques are used: positron emission tomography (PET), which reveals ...

PET scans monitor brain circuits activated by light, opening new window to brain diseases

April 11, 2013
(Medical Xpress)—Building on their history of innovative brain-imaging techniques, scientists at the U.S. Department of Energy's Brookhaven National Laboratory and collaborators have developed a new way to use light and ...

Molecular imaging improves care for children with brain cancer

June 11, 2013
A relatively new weapon in the fight against childhood brain cancer has emerged that improves upon standard magnetic resonance imaging (MRI) by providing information about tumor metabolism and extent of cancer in children ...

Recommended for you

Researchers find monkey brain structure that decides if viewed objects are new or unidentified

August 18, 2017
A team of researchers working at the University of Tokyo School of Medicine has found what they believe is the part of the monkey brain that decides if something that is being viewed is recognizable. In their paper published ...

Artificial neural networks decode brain activity during performed and imagined movements

August 18, 2017
Artificial intelligence has far outpaced human intelligence in certain tasks. Several groups from the Freiburg excellence cluster BrainLinks-BrainTools led by neuroscientist private lecturer Dr. Tonio Ball are showing how ...

Study of nervous system cells can help to understand degenerative diseases

August 18, 2017
The results of a new study show that many of the genes expressed by microglia differ between humans and mice, which are frequently used as animal models in research on Alzheimer's disease and other neurodegenerative disorders.

How whip-like cell appendages promote bodily fluid flow

August 18, 2017
Researchers at Nagoya University have identified a molecule that enables cell appendages called cilia to beat in a coordinated way to drive the flow of fluid around the brain; this prevents the accumulation of this fluid, ...

Researchers make surprising discovery about how neurons talk to each other

August 17, 2017
Researchers at the University of Pittsburgh have uncovered the mechanism by which neurons keep up with the demands of repeatedly sending signals to other neurons. The new findings, made in fruit flies and mice, challenge ...

Neurons involved in learning, memory preservation less stable, more flexible than once thought

August 17, 2017
The human brain has a region of cells responsible for linking sensory cues to actions and behaviors and cataloging the link as a memory. Cells that form these links have been deemed highly stable and fixed.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.