Bone Densitometry (Quantitative Computed Tomography)
What is QCT (Quantitative Computed Tomography)?
It is a high-tech medical software that allows measurement of the vertebral and femoral bone densities by means of a tomography device.
What are the Superiorities of QCT Over DEXA?
DEXA is a 2-dimensional system, therefore, it can measure the sum of the cortical and spongious bone densities. However, osteoporosis is the reduction of the spongious bone densities first. In elderly patients, findings associated with spinal degeneration (arthrosis-arthritis-calcifications) often will be found, and this will lead to the increases in the intensity of the cortical bone. Therefore even in a patient with osteoporosis (bone loss), the DEXA method may display the bone density measurements within normal limits.
QCT can perform only for 3-dimensional measurements, therefore, it can measure only the spongious bone density. As the actual defect is in the spongious bone in osteoporosis, QCT provides a high potential for a more accurate and earlier diagnosis.
In addition, owing to its 3-dimensional measurement feature, in obese patients too, QCT provides more accurate results.
QCT provides unique experiences to the users, especially in the spinal measurements. The measurement by QCT is possible by discrimination of the trabecular bone from the cortical part. In conditions creating major issues in DEXA measurements, this feature enables measurements with 100% accuracy. Some of these conditions are degenerative changes in bones, lumbar superimpositions in cases with scoliosis, out-of-bone calcifications, and obesity.
QCT gives T-scores as well in femoral measurements just like DEXA. On the other hand, QCT does not cause positional difficulties during the scanning procedure, unlike DEXA. For example, giving a position to a patient with hip osteoarthritis is quite difficult.
In addition, QCT can be safely used in all patients with narrower discal spaces, with degenerative disorders, with aortic calcifications, and osteophytosis.