January 30, 2017

Reinventing MRI

U of M team’s efforts to create a smaller, cheaper brain MRI machine paves the way for an innovative technology that could have far-reaching benefits

In the Center for Magnetic Resonance Research (CMRR) lab of Michael Garwood, Ph.D., University of Minnesota scientists have designed a portable, less expensive way to get high-quality images of the brain. It’s part of the National Institutes of Health’s BRAIN Initiative. 

Now Garwood hopes to build the head-only MRI scanner his team has sketched out. It looks a lot like a chair at a hair salon, but in functionality, it’s revolutionary.

Most magnetic resonance imaging today is done in the same way it’s been done for the past four decades: in a noisy machine that could cost between $1 million and $2 million and takes up an entire room. A portable, less expensive MRI machine could bring a very sensitive diagnostic tool to the 90 percent of the world that is currently without access, as well as significantly lower health care costs in the wealthier parts of the world that do have MRI access, says Garwood, a professor in the Medical School’s Department of Radiology. 

So why hasn’t anyone done this before?

“We couldn’t make a [good] image with those magnets without reinventing MRI,” Garwood says, “so that’s what we did in this project.”

Typical MRI technology requires that the magnetic field over the object being imaged is extremely uniform—only varying by only 1 or 2 parts per million. “That means the magnet is this big thing relative to the object,” he explains.

Creating a smaller and lighter machine hadn’t been possible because it meant losing uniformity in the magnetic field, which would result in less-detailed images. Or so scientists believed.

Using a different way to excite MR signals that overcome imperfections in the magnetic field, Garwood’s team showed that, even with 3,000 times less uniformity than a standard hospital MRI scanner, it’s still possible to get quality images. Garwood took images of his own brain to show that it worked.

“It’s a smaller tube, all the same technology,” he says. “We can now make good images with a magnet that’s not very uniform, which means that now we can make it small, and you can imagine that it’s going to be a lot cheaper.” 

A critical need in diabetes research

Smaller, lighter, and cheaper MRI is a good thing all around. The legwork Garwood’s team did to create this next-generation technology was especially useful when collaborator Klearchos Papas, Ph.D., a diabetes researcher at the University of Arizona, approached the CMRR for help with a special project.

Papas is studying whether an implantable “bioartificial pancreas”—a permeable pouch that’s about 4 cm long, 1 cm wide, and just a few millimeters thick—could provide people who have type 1 diabetes with functional insulin-producing beta cells without the need for immunosuppression.

The pouch is a commercially available device called TheraCyte that’s being modified for Papas’s project. In a pilot clinical study, which Papas hopes will begin in two years, the device containing islets (clusters of beta cells) will be implanted just under the skin of a diabetic person’s forearm. The islets need oxygen to function optimally—not too little and not too much—so being able to noninvasively measure the oxygen level inside of the device will be imperative to the study’s success.

Today a $180,000 gift from the Schott Foundation is allowing Garwood’s team to build a prototype of an inexpensive, tabletop MR spectroscopy scanner just for a person’s arm that will accomplish this. And fortunately, they didn’t have to create the technology from scratch.

“We’re basically taking advantage of a lot of what we’ve learned from the BRAIN project,” Garwood says.

The Schott Foundation supported research leading up to the TheraCyte pilot study, too, along with the Minnesota Lions Diabetes Foundation Inc., JDRF, and the Carol Olson Memorial Diabetes Research Fund.

“They were critical,” Garwood says. “They’ve just been such wonderful supporters, financially and with enthusiasm. … It wouldn’t have been possible to get this off the ground without them.”

Papas agrees. It took a while for the larger funding agencies to recognize the need to monitor oxygen in the implanted device, he says, but these funding partners supported the potential of the work early and allowed Papas and his colleagues to gather enough data to get the bigger funders on board as well.

“It was instrumental to get these pilot funds,” he says. “What a wonderful group of people.”

Going beyond

Plenty of other areas of medicine could benefit from cheaper, more portable MRI technology, too, Garwood says. Breast cancer screening is one.

“MRI has about 99 percent sensitivity to detect a lesion in the breast,” he says. “It always bothered me that here we have this ultimate technology while we’re missing 25 percent of cancers in premenopausal women with mammography. But we use [mammography] because it’s cheap and widely available. I think that’s a huge problem.”

But if the size and portability of the MRI machine and the cost of an MRI scan could come close to matching those of mammography—a tall order, Garwood admits—it would be easier for the medical community to make the commitment to switch.

“MRI is the ultimate screening method,” he says. “We just have to get the technology out there.”

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