Computed tomography (CT) scans done for various reasons are also an effective way to screen for osteoporosis, according to Dr. Perry Pickhardt, professor of radiology at the UW School of Medicine and Public Health.
“We found that accurate bone-density information can be available from CT exams ordered for other things, and requires no additional cost, patient time, equipment, software or radiation exposure,” said Dr. Pickhardt in the study published today in the Annals of Internal Medicine.
Pickhardt compared 2,063 pairs of CT and DXA (dual X-ray absorptometry, a standard way to measure bone density) in 1,867 adults. The pairs of scans were examined retrospectively and were performed no more than six months apart between 2000 and 2009.
The abdominal CT exams were done for a variety of reasons, including suspected masses or oncologic workup, gastrointestinal issues or unexplained abdominal pain, genitourinary concerns and virtual colonoscopy.
The DXA tests showed almost 23 percent of those scanned had osteoporosis; 45 percent had intermediate bone-mineral density; and 32 percent had normal bone density. CT exams were able to accurately detect cases of osteoporosis with either 90% sensitivity or 90% specificity, depending upon the desired goal.
“One clear advantage of CT over DXA for bone-density testing is its ability to accurately identify unsuspected osteoporotic compression fractures which clearly diagnose osteoporosis,” said Pickhardt.
Pickhardt said that bone density can be determined retrospectively by a radiologist or non-radiologist because CT scans are now typically stored indefinitely in electronic medical records.
“The method that we used to check for osteoporosis requires a negligible amount of training and time and could be looked at prospectively or retrospectively by a radiologist or even a non-radiologist,” said Pickhardt. “Plus, the method adds no cost or additional patient time or radiation exposure.”
Pickhardt said that even though optimal implementation of CT screening for osteoporosis still needs to be determined, the data indicates it could be used in practice depending on clinical objectives.
The study was supported by grants from the National Institutes of Health (1R01CA144835-01 and 1R01CA169331-01).
University of Wisconsin School of Medicine and Public Health