In patients with ankylosing spondylitis, a moderate correlation and fair agreement between the T-scores of hip and the lumbar spine has been reported, suggesting that DXA of the hip and the lumbar spine may both be useful for screening in patients with ankylosing spondylitis without fused spines [111]. In addition to degenerative changes in the spine, BMD measurements using DXA may also be spuriously elevated in patients with hemoglobinopathies who have an iron-overloaded liver and in patients with severe abdominal calcifications [112,113]. QCT The literature indicates that QCT is ideally suited for the evaluation of the spine in the setting of advanced degeneration of the spine; it is preferred over DXA for monitoring under these conditions as well. Because it selectively samples only the cancellous portion of the vertebral body and excludes the end plates, cortices, and posterior elements, BMD using QCT is generally not negatively impacted by arthritis in the spine and has greater sensitivity to change than in DXA in this group of patients [32,114]. It also may provide adjunctive information in preoperative patients who may have diminished bone density [115]. Osteoporosis and Bone Mineral Density QUS There is insufficient evidence to support the use of QUS as a screening study for low BMD in patients with advanced degenerative changes in the spine. Radiography Appendicular Skeleton There is insufficient evidence to support the use of radiography appendicular skeleton as a screening study for low BMD in patients with advanced degenerative changes in the spine. Radiography Axial Skeleton There is insufficient evidence to support the use of radiography axial skeleton as a screening study for low BMD in patients with advanced degenerative changes in the spine. SXA There is insufficient evidence to support the use of SXA as a screening tool for low BMD in patients with advanced degenerative changes in the spine.
Osteoporosis and Bone Mineral Density. In patients with ankylosing spondylitis, a moderate correlation and fair agreement between the T-scores of hip and the lumbar spine has been reported, suggesting that DXA of the hip and the lumbar spine may both be useful for screening in patients with ankylosing spondylitis without fused spines [111]. In addition to degenerative changes in the spine, BMD measurements using DXA may also be spuriously elevated in patients with hemoglobinopathies who have an iron-overloaded liver and in patients with severe abdominal calcifications [112,113]. QCT The literature indicates that QCT is ideally suited for the evaluation of the spine in the setting of advanced degeneration of the spine; it is preferred over DXA for monitoring under these conditions as well. Because it selectively samples only the cancellous portion of the vertebral body and excludes the end plates, cortices, and posterior elements, BMD using QCT is generally not negatively impacted by arthritis in the spine and has greater sensitivity to change than in DXA in this group of patients [32,114]. It also may provide adjunctive information in preoperative patients who may have diminished bone density [115]. Osteoporosis and Bone Mineral Density QUS There is insufficient evidence to support the use of QUS as a screening study for low BMD in patients with advanced degenerative changes in the spine. Radiography Appendicular Skeleton There is insufficient evidence to support the use of radiography appendicular skeleton as a screening study for low BMD in patients with advanced degenerative changes in the spine. Radiography Axial Skeleton There is insufficient evidence to support the use of radiography axial skeleton as a screening study for low BMD in patients with advanced degenerative changes in the spine. SXA There is insufficient evidence to support the use of SXA as a screening tool for low BMD in patients with advanced degenerative changes in the spine.