Dual-energy X-ray absorptiometry in diagnosis of osteoporosis: Basic principles, indications, and scan interpretation

Abstract

Dual-energy x-ray absorptiometry is currently the most commonly used modality for the diagnosis of osteoporosis, allowing fast, accurate, and noninvasive measurements of bone mineral density. In this review we discuss the principles, applications, advantages, and limitations of this diagnostic technique.

Osteonecrosis of the Femoral Head in an 8-Year Old Boy: Appraisal of Evolution by DXA

“…Skeletal health in youth can be assessed by DXA, quantitative computed tomography, peripheral quantitative computed tomography, quantitative ultrasonography, MR imaging, or radiogrammetry. DXA is now established as the state-of-the-art modality for noninvasive assessment of bone density because of its availability, reproducibility, speed, and low exposure to ionizing radiation [ 6 7 ]. Because of the relatively high resolution of fan-beam DXA scanners, anatomical details of the examined region may be clearly depicted on the DXA generated images [ 6 7 8 ].…”

“…DXA is now established as the state-of-the-art modality for noninvasive assessment of bone density because of its availability, reproducibility, speed, and low exposure to ionizing radiation [ 6 7 ]. Because of the relatively high resolution of fan-beam DXA scanners, anatomical details of the examined region may be clearly depicted on the DXA generated images [ 6 7 8 ]. Correlation with radiography may be required however, to better define the disease process and to exclude potential sources of diagnostic error.…”

“…This is owing to the fact that both resolution and signal-to-noise ratio of DXA scans are inferior to those of radiographs, and as such DXA can only supplement and not rather replace radiographs [ 6 7 8 ]. As a rule of thumb, the scan images on the DXA printout need to be carefully reviewed for the presence of potential sources of diagnostic error such as improper patient positioning and placement of regions of interest (ROIs), osteosclerosis, metallic items, fractures and degenerative disease [ 7 8 9 ]. Additional sources of error include motion artifacts, retained intestinal barium, nasogastric tube, spinal scoliosis, and spinal orthopedic hardware.…”

Imaging modalities in the assessment of osteoporosis

“…Dual-energy x-ray absorptiometry is the only technique available that can measure BMD at both the lumbar spine and proximal femur, the sites where the most clinically important osteoporotic fractures occur. [33][34][35][36][37][38][39][40][41][42][43][44][45][46] Total body DXA scans can be used to calculate total body bone mineral, lean body mass, and fat body mass. [33][34][35][36][37][38][39][40][41][42][43][44][45][46] Dual-energy x-ray absorptiometry has also been used to study bone resorption adjacent to hip prostheses.…”

“…[33][34][35][36][37][38][39][40][41][42][43][44][45][46] Total body DXA scans can be used to calculate total body bone mineral, lean body mass, and fat body mass. [33][34][35][36][37][38][39][40][41][42][43][44][45][46] Dual-energy x-ray absorptiometry has also been used to study bone resorption adjacent to hip prostheses. In conclusion, DXA is a safe (minimal radiation exposure), noninvasive and relatively easy to perform method that has become widely accepted in the assessment of BMD.…”