MR-PET, Other Advances Take Center Stage At RSNA 2015

By: 
Gary Boas
February 24, 2016
Bruce Rosen discussed the latest MR-PET research at RSNA 2015

Simultaneous MR-PET and other research coming out of the MGH Martinos Center for Biomedical Imaging was highlighted at the 2015 annual meeting of the Radiological Society of North America (RSNA) in December, including in a talk by Center Director Bruce Rosen.

The RSNA annual meeting is one of the world’s leading forums in which to share cutting-edge research in radiology. The weeklong event—held in Chicago every fall—brings together tens of thousands of clinicians, investigators and other medical imaging professionals to report on and discuss the latest developments in the field.

Some of these developments are compelling researchers and clinicians to reimagine the radiology landscape. In the Annual Oration on Diagnostic Radiology—entitled “Trends and Developments Shaping the Future of Radiology”—MGH Radiology Chairman Emeritus James Thrall detailed four trends in particular that are already impacting our understandings of what is possible with medical imaging.

Among them: the implementation of “special purpose” medical imaging devices. As an example, Dr. Thrall highlighted recent work coming out of the Martinos Center: an inexpensive portable MR imaging device that Larry Wald, Clarissa Cooley and colleagues are developing to facilitate greater access to MRI at the point of care. “We've always required patients to come to us," Dr. Thrall said. "Moving technology to the patient allows more coordination of care.”

Martinos Center investigators are also deeply involved in another of the trends outlined by Dr. Thrall: the development of hybrid, “multimodal” imaging approaches such as the integration of magnetic resonance imaging and positron emission tomography. Later in the week, Center Director Bruce Rosen spoke at greater length about the latest advances in MR-PET research.

Tackling disease with simultaneous MR-PET

In his talk, “Combined MR and PET: Perspective for Research,” Dr. Rosen discussed the many avenues by which the hybrid technique can benefit a range of applications—and indeed move them forward in ways we haven’t seen before. These are possible, he said, because MR and PET are “wonderfully complementary, truly the Yin and Yang of each other.”

How so? MRI is noninvasive, he said, and provides both high resolution and an excellent ability to image anatomical detail and physiology like blood flow, but it has poor sensitivity and quantification is difficult.

PET, in contrast, while offering lesser resolution and limited anatomical detail, has exquisite sensitivity, is more readily quantifiable and—most importantly, perhaps—allows us to study a broad range of biological processes.

Because they complement each other so well, the integration of the two modalities opens up a number of new opportunities for researchers.

Dr. Rosen described a broad range of basic science, clinical and translational research opportunities afforded by simultaneous MR-PET—opportunities to glean new understandings of human biology and put them into practice in the clinic. Included among these are advanced applications such as image-guided surgery for the treatment of epilepsy and monitoring of the effects of therapy in cancer and in multiple sclerosis patients.

He noted, for example, work by Martinos Center investigator Caterina Mainero, who is using MR-PET to study cortical disease in multiple sclerosis patients. Looking ahead, the technique could also help in exploring how cortical disease responds to different treatments in these patients.

Dr. Rosen also highlighted a study by the Martinos Center’s Marco Loggia and colleagues adding important insights to our understandings of chronic pain.

The study, published last year in the journal Brain, found the first evidence of increased inflammation in the brains of chronic low back pain patients—demonstrating that this is, in fact, not just a disease of the lower back. Here, PET scans showed increased microglial activations in the patients’ brains while functional MRI scans enabled the researchers both to localize the activations and to determine whether the chronic pain is impacting a broader range of networked brain functions.

These findings are significant, not least because they point toward a possible means of treating chronic pain. They “suggest a mechanism by which this chronic pain cycle is persistent in the brain,” Dr. Rosen said, adding that they also “give us some hope that by addressing the inflammatory component in the brain we may be able to break this cycle.”