Artifacts Affecting Dual-Energy X-Ray Absorptiometry Measurements

Objective: To present 3 cases in which the presence of artifacts altered the dual-energy X-ray absorptiometry (DXA) measurements of bone mineral density (BMD) in the lumbar field. Methods: Clinical presentation and literature review. Results: The first patient was a 49-year-old premenopausal woman with a spinal cord stimulator implanted in her lumbar spine. The implant increased the measured BMD in the lumbar region from osteopenia to normal range. The second patient was a 56-year-old man who had a DXA scan after he was administered oral and intravenous iodine-based contrast earlier the same day. The oral contrast in the patient's colon created a dense artifact, which overlapped the lumbar spine and adjacent soft tissue. The effect almost changed his DXA diagnosis from osteoporosis to osteopenia. The third patient was a 64-year-old woman who had undergone laparoscopic adjustable gastric banding (LAGB). A part of the LAGB system adjacent to lumbar vertebra 3 was mistakenly included as part of the vertebrae by the DXA scanner, causing an increase in the measured BMD. Conclusion: There are numerous artifacts that can alter DXA BMD measurement. It is important for providers who interpret DXA scans to be familiar with the potential effects of artifacts and how to adjust for their presence, since erroneous measurements can lead to incorrect decisions regarding treatment and follow-up.