Artifacts Affecting Dual-Energy X-Ray Absorptiometry Measurements

Abstract

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. (AACE Clinical Case Rep. 2019;5:e263-e266) Abbreviations: BMD = bone mineral density; DXA = dual energy X-ray absorptiometry; FRAX = Fracture Risk Assessment Tool; ISCD = International Society for Clinical Densitometry; L = lumbar vertebra; LSC = least significant change; ROI = region of interest e264 DXA Artifacts, AACE Clinical Case Rep. 2019;5(No. 4)

The choice of region of interest after spinal procedures alters bone mineral density measurements

“…In order to determine whether there is more than a 1.0 T-score difference between the vertebra in question and adjacent vertebrae and to exclude the questionable level from the analysis, technologists must include the vertebra in question in the ROI. Thus far, the first method has been performed in clinical practice, and related case reports has been published in the literature [ 6 ]. Therefore, the present study aimed to investigate the influence of spinal metallic implants and bone cement on lumbar spine BMD measurements, with the ROI including or excluding the vertebrae affected by artifacts.…”

“…Owing to the DXA methodology, high-density materials such as metallic prostheses and bone cement may affect bone mineral density (BMD) measurements. In particular, the presence of high-density materials such as catheters, contrast agents, and spinal cord stimulators can increase BMD measurements [4][5][6]. Tantalum surgical clips, which appear black on DXA, can further decrease BMD measurements, whereas they appear white on radiography [4].…”

Diagnosis and Management of Sarcopenia after Hip Fracture Surgery: Current Concept Review

“…In addition, in patients with hip fractures, accurate evaluation of muscle mass using dual energy X-ray absorptiometry (DEXA) measurement-based sarcopenia diagnosis is difficult due to surgical implant metal artifacts 8) . Therefore, establishment of a new definition of sarcopenia specific to patients with hip fractures is necessary for quality management of postoperative sarcopenia.…”