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BY TOM MAJESKI. Bipolar disorder is a serious mental illness affecting about 2.3 million Americans, yet it can be difficult for doctors to diagnose. ... http://www.twincities.com/mld/pioneerpress/news/local/10273359.htm
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Posted on Fri, Nov. 26, 2004
Scanner may give bipolar diagnosis
Brain chemical differences offer hope of identifying disease
BY TOM MAJESKI
Bipolar disorder is a serious mental illness affecting about 2.3 million Americans, yet it can be difficult for doctors to diagnose. That may soon change, thanks to groundbreaking research at the Mayo Clinic in Rochester, Minn.
Using a high-powered magnetic resonance scanner, researchers have found that patients with bipolar disorder produce significantly different brain scans than patients without the disorder.
"We're trying to come up with a way to turn this into a diagnostic tool," said Dr. John Port, an assistant professor of radiology and a consultant at Mayo. "The psychiatric community clearly needs a tool to help diagnose bipolar disorder." Researchers hope the specialized scanning can help identify "metabolic markers of the disease," he said.
Bipolar disorder is a mental condition characterized by alternating periods of euphoria and depression. Currently, it is diagnosed by psychiatrists using symptoms, response to medications and, when available, family history. Patients often go undiagnosed for years, doctors say.
According to the National Institute of Mental Health, two-thirds of patients with bipolar disorder are unemployed, suicide rates are 20 times higher than normal and 40 percent to 60 percent are substance abusers.
Mayo Clinic physicians see about 1,000 patients a year with bipolar disorder, Port said.
"It's a horrible disease," he said. "It's a major health care crisis."
In a research paper presented Tuesday at the Radiological Society of North America's annual meeting in Chicago, Port and his colleagues explained the results of a study that involved 42 patients, half with bipolar disorder and half without. They ranged in age from 18 to 54 and included 26 women and 16 men.
Port said the study was unique because the participants were not taking any medications and were not substance abusers.
"If we're going to build a tool to pick up bipolar disease, we have to have a group as pure as possible," Port said. By eliminating medications and addictive substances, he and his colleagues know exactly what they are measuring
As part of the study, the 42 participants underwent magnetic resonance spectroscopy, a special type of MR imaging that allows researchers to analyze the chemical properties of tissue.
"We're getting a bunch of wavy lines that tell the chemical makeup of the brain," Port explained.
The researchers studied 60 to 70 regions of the brain at a time and then used the scans to perform statistical analysis on 14 separate areas and five metabolites, or chemical substances, found in the brain.
Dr. Paul Goering, medical director for psychiatry at St. Paul's United Hospital, finds the Mayo report "intriguing," but points out that it's a small study and that other promising diagnostic tests for brain disorders, such as Alzheimer's, have not panned out.
"Clinical interviews are the best tool we have" for diagnosing bipolar disorders, Goering said. "If we add a better tool, that's always welcome. But this is a very small study. Are they really significant findings, or were they coincidental? I'll be curious to see what a bigger sample shows. It doesn't have the muscle to be useful for me now because it's speculative."
Preliminary findings of the Mayo study indicate that certain chemical levels differed significantly between the bipolar group and the control group in four areas of the brain that control behavior, movement, vision and reading, and sensory information.
The MR scanner used in the study is about twice as powerful as an MR scanner found in a typical hospital, Port said. However, more powerful scanners are being installed in hospitals all across the country, so finding a suitable scanner will not be a problem if ongoing tests conclude that the technique can be used as a diagnostic tool, Port said.
"We're going to keep going with this," he said of the research project. "We think we've got a good tool, but we certainly can improve it."