Limitations of Quantitative CT in Corticosteroid Induced Osteopenia

Abstract

Single energy spectrum quantitative CT (SES-QCT) was applied for the assessment of the trabecular bone mineral status in patients under long-term corticosteroid treatment. Seventeen renal graft recipients (RGR) and 12 patients receiving corticosteroid treatment for collagen disease were studied. A reduction of about 40% in the spinal trabecular bone density relative to matched controls was found, associated with the corticosteroid administration. Repeated measurements showed significant reduction in density 4 months after transplantation, and an increase in density after graft rejection. Radiologic or clinical evidence of osteopenia in the spine was not found. Other non-invasive techniques, applied in the upper extremities of the RGR, showed only minor bone reduction compared to controls. The findings of the present study suggest that adipose tissue deposition in the spinal trabeculae can introduce errors in the measurements. Therefore, SES-QCT should not be applied during corticosteroid therapy.

Body Composition in Homozygous β‐Thalassemia

“…The latter finding is attributed to an artifact of the technique used. SES‐QCT measures bone mineral density under the assumption that the composition of the organic fraction of the bone in patients does not differ from that in controls 5. However, β‐thalassemia major is characterized by hyperplasia of the red bone marrow.…”

“…SES-QCT measures bone mineral density under the assumption that the composition of the organic fraction of the bone in patients does not differ from that in controls. 5 However, β-thalassemia major is characterized by hyperplasia of the red bone marrow. Indeed, yellow-marrow suppression was shown to exist in the spinal trabecular bone of the patient studied by MRI.…”

Software Upgrading in a CT Scanner

“…Therefore, the density values of any patient obtained with the new software should be corrected either when compared to normative data, or when evaluated in a longitudinal study. Further investigation is needed involving more scanners for which software upgrading is planned, and torso phantoms which contain additional materials to simulate fat and collagen (12).…”

Rheumatoid arthritis and osteoporosis

“…For CT scanners operating at 140 KVp this amounts to 15 mg/ cm 3 for each 100 mg/cm 3 of fat with SE-QCT and Ô 7 mg/cm 3 for DE-QCT. A change of 100 mg/cm 3 can occur rapidly with corticosteroids, leading to an apparent decrease of bone density (42).…”