Nov. 7, 2011 X-ray images known as CT scans can help confirm gout in patients who are suspected of having the painful condition but receive negative results from traditional tests, a Mayo Clinic study has found. The type of CT scan analyzed, dual-energy computed tomography, also is valuable for diagnosing people who cannot be tested with the typical method of drawing fluid from joints, researchers found.
The study is being presented at the American College of Rheumatology annual scientific meeting in Chicago.
Gout -- the buildup of uric acid crystals in and around joints, causing inflammation and painful, potentially disabling flare-ups -- has historically been portrayed as a disease of the wealthy, but it afflicts people from all walks of life. Men are more likely to develop gout, but women's risk rises after menopause, when their uric acid levels approach those of men. Treatment usually involves medication and dietary changes.
Physicians traditionally check for gout by using a needle to draw fluid from affected joints and examining the fluid for uric acid crystals. Dual-energy CT scans were recently modified to detect the crystals, and the study found the scans "very accurate" in identifying patients with gout, says lead researcher Tim Bongartz, M.D., a rheumatologist at Mayo Clinic in Rochester, Minn.
"We wanted to really challenge the new method by including patients who were only a few days into their first flare of gout," Dr. Bongartz says.
Dr. Bongartz notes that CT scans are significantly more expensive than the standard test for diagnosing gout. He also cautions that, while highly accurate overall, in one subgroup of patients studied -- those with very acute gout -- the CT scan failed to identify 30 percent of cases. The new tool is most helpful when joint fluid cannot be obtained or the fluid analysis comes back negative even when gout is strongly suspected, he says.
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