Gadolinium is the preferred tracking enhancer for an MR exam, but new research has emerged to showcase a more biologically friendly and perhaps cheaper alternative.

Researchers at the University of California, San Diego School of Medicine, led by Eric T. Ahrens, Ph.D., professor of radiology and senior author, and Roger Tsien, Ph.D., professor of pharmacology, chemistry and biochemistry, whose work has also earned him a share of the 2008 Nobel Prize in chemistry, have found that, when paired with iron, the agent fluorine-19 allowed for easier tracking of stem cells and immune cells.

The agent is considered a nanoemulsion, the droplets ranging in size from 50 to 1000 nanometers. By dissolving the iron into the fluoride agent, the ability for the MR to detect the fluorine increased, making it a highly sensitive probe so that the MR was able to locate the droplets with little difficulty.
“Fluorine-19 tracer agents are an emerging approach that produces positive signal hot-spot images with no background signal because there’s virtually no fluorine concentration in tissues,” said Ahrens, in a statement.

With this advancement, clinicians can noninvasively monitor the cells in living persons, helping with the development of future therapies such as immunotherapy, stem cell, and treating inflammation.

Iron has never been considered as an enhancer for fluoride-based MR signals, reported Ahrens, and yet their study has shown that iron may actually be superior to the other metals used for MR, such as gadolinium.

Recently, gadolinium has been making headlines due to the fact that it may accumulate in the brain.

The usage patterns for gadolinium-enhanced MR exams have been impacted both nationally and internationally, according to Dr. Emanuel Kanal, a professor of radiology and the director of MR services at the University of Pittsburgh Medical Center.

However, it still remains an important part of an MR exam and — unless a good alternative is found — that's not likely to change soon.

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