By Charlene Laino
CHICAGO -- December 3, 2008 -- Computed tomography (CT) colonography can be used to screen patients for osteoporosis, according to a retrospective study presented here on December 2 at the Radiological Society of North America (RSNA) 94th Annual Meeting.
"If physicians are thinking of sending a patient for colon cancer screening, they may want to opt for CT colonography as then you can determine bone mineral density too," said Rizwan Aslam, MBChB, Department of Radiology, University of California, San Francisco, San Francisco, California.
Recent studies suggested that virtual colonography is as accurate as colonoscopy.(1) And this year, the American Cancer Society, the American College of Radiology, and the US Multi-Society Task Force on Colorectal Cancer added CT colonography to the list of colon cancer screening options.
Currently, fewer than 40% of patients are sent for colon cancer screening, Dr. Aslam said. The added benefit of being able to screen for osteoporosis using CT colonography may help improve the dismal statistic, he said.
The study, conducted at the San Francisco Veterans Administration Hospital, involved 30 men and 5 women aged 54 to 79 years who underwent CT scans on a 16-slice multidimensional CT scanner.
Two readers independently calculated bone mineral density (BMD) and T scores from the datasets obtained using the CT colonography data. CT BMD analysis was performed on a workstation using a standard "off-the-shelf" bone mineral analysis package, Dr. Aslam said.
When the bone mineral density measurements obtained from the CT colonography scans were compared with those obtained using dual energy x-ray absorptiometry (DEXA) the researchers observed "excellent correlation," Dr. Aslam said.
For all vertebra, there was a correlation of 0.66 (P < .0001) and 0.61 (P < .0001) for the CT and DEXA BMD readings for readers 1 and 2, respectively. For T scores, there was a correlation of 0.6 (P < .0001) and 0.59 (P < .0001) for readers 1 and 2, respectively.
"CT colonography isn't a replacement for DEXA testing, but it could be a way to screen more people for osteoporosis using software that any physician can obtain," he said.
1. CD Johnson et al. N Engl J Med. 2008;359:1207-1217.
[Presentation title: Assessment of Bone Mineral Density on CT Colonography. Abstract SSG13-09]
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