Two Birds, One Scan

Osteoporosis detection may be possible with CT scans ordered for other health concerns

(RxWiki News) CT scans are a pretty common tool in modern medicine. So it would be pretty neat if docs could also screen for bone loss by looking at a CT scan that was done for another health condition.

In a recent study, researchers compared standard computed tomography (CT) scans to special osteoporosis scans to see if the CT scan could also gauge bone density.

The results showed that doctors might be able to detect signs of osteoporosis in stomach CT scans that had been ordered for other health reasons.

"Women 65 and over — get tested for osteoporosis."

Perry J. Prickhardt, MD, from the Department of Radiology at the University of Wisconsin in Madison, WI, led an investigation into the use of stomach CT scans to spot signs of osteoporosis.

Bone tissue is constantly being absorbed and replaced by the body. Inside a living person’s bones, new cells must be constantly generated or bones can lose density and become brittle.

The health condition of weak bones, due to lack of bone density, is known as osteoporosis. When a person has low bone density, but not low enough to qualify as osteoporosis, they have osteopenia.

Dual-energy x-ray absorption (DEXA) is a special type of scan that can measure a person’s bone density. DEXA scans only take 10-15 minutes and usually run around $200.

For this study, the researchers compared stomach area CT scans and DEXA scans in 1,867 patients to determine if CT scans could also detect signs of osteoporosis. For each patient, the CT and DEXA scans were done within 6 months of each other.

CT scans are more expensive than DEXA scans, ranging between a few hundred and a few thousand dollars, depending on the facility. But CT scans are used all the time and for a number of reasons. Both scans expose the body to radiation.

The idea behind this study was to see if stomach area CT scans that were taken for other health reasons could also double as a way to detect osteoporosis as an added bonus.

The researchers found that the CT scans were 90 percent accurate at diagnosing osteoporosis when the lowest unit of measure was applied. The CT scans were also 90 percent accurate at showing the difference between osteoporosis, osteopenia and normal bone density levels at the lowest unit of measure.

When the greatest unit of measure was used, the CT scans were 99 percent accurate at showing the differences between osteoporosis, osteopenia and normal bone density.

The authors concluded that stomach area CT scans done for other health reasons could also help doctors identify osteoporosis without adding costs or radiation exposure.

In a related editorial, Sumit R. Majumdar, MD, from the University of Alberta in Canada said, “With more than 80 million CT scans performed in the United States each year, the idea of extracting more information from imaging data collected for other purposes holds merit.”

“[T]he main clinical issue for osteoporosis is underdiagnosis from undertesting,” Dr. Majumdar said.

But Dr. Majumdar went on to point out that this study had many limitations including no recommendations for doctors on what CT scan configurations and specifications should be used to help diagnose or rule out osteoporosis.

However, Dr. Majumdar did agree that that using a CT scan that already had to be taken for another health reason might help “rule in” potential osteoporosis patients for further testing.

This study was published in April in the Annals of Internal Medicine.

The National Institutes of Health provided funding support for this project. No conflicts of interest were reported.

Review Date: 
April 16, 2013