Change agent: Creating new scans to track brain diseases
by Sarah C.p. Williams
Seven weeks after weight-loss surgery, a group of women have seen significant changes in their body shapes and sizes. They're each down 20 to 30 pounds, but that's not the only change their bodies are going through.
The women's weight loss is caused by a change in appetite, which results from changes in brain function, explains UAB neuroradiologist Robert Kessler, M.D. (pictured above in UAB's Advanced Imaging Facility). On positron emission tomography (PET) scans, Kessler can see an obvious transformation in the women's brains, particularly in dopamine neurotransmission.
Using a specialized brain PET scan that he has developed, Kessler can visualize levels of dopamine receptors—molecules that help transmit the brain's messages of motivation and reward. Before surgery, the women had increased levels of the receptors, which appear on the PET scans as glowing white patches throughout the brain. But after their surgeries, these changes have faded; the women's brains exhibit a more balanced map of dopamine receptors. In real-world terms, Kessler thinks, these tempered receptor levels reflect a shift to a more normal reward perception, helping the women control their appetites after surgery.
Obesity—and the drive to overeat—isn't the only pathology that Kessler can see when he peers into people's brains with a PET scan. During the past 30 years, he has helped illuminate changes to the brain that might underlie schizophrenia, drug addiction, depression and dementia, among other disorders. By looking at a person's brain PET scan and carefully measuring the levels of neurotransmitter function, Kessler can tell whether someone is more prone to taking risks than average, whether they're more of a "slacker" or a "go-getter," and whether or not they have "the ability to experience rewarding stimuli in a normal manner or if they have lost that ability," he said.
Kessler, who joined the UAB faculty in 2013 as director of neurochemical brain imaging and PET neurotracer development in the Department of Radiology, says these specialized PET scans are paving the way toward a new level of understanding of brain diseases. "At a very basic scientific level, there's no other technology that can look at the human brain and inform you about specific molecules and receptors," Kessler said. At UAB, he's taking advantage of the university's TR24 cyclotron—the largest at any U.S. academic medical center—to develop new PET scans. And he has launched collaborations with UAB researchers across the psychiatric and neurological sciences to help them apply his techniques to even more questions.
http://medicalxpress.com/news/2015-01-a ... eases.html
http://www.redorbit.com/news/health/111 ... sm-111614/
http://www.scienceclarified.com/Qu-Ro/R ... acers.html
12 Jan 2015, 9:36 am
