Computerized tomography scanning (CT scan) appears to help in the diagnosis of gout. The type of CT scan analyzed, dual-energy computed tomography, is also 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.
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 likelier to develop gout, but women's risk rises after 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.
Siemens Medical Solutions provided software to be used on one of the systems involved in the study and provided partial salary support through an unrestricted research grant to the CT Innovation Center.