[Computer tomographic densitometry of the normal vertebral body spongiosa]

The absorption values of cancellous bone of the third lumbar vertebral body were measured in 80 patients by CT. It was possible to demonstrate a statistically significant linear correlation between absorption values and patient age. The older the patient, the lower the average absorption values of cancellous bone. The average absorption values in patients between 20 and 30 Jrs. were found to be about 200 HU, between 30 and 50 Jrs. 180, between 60 and 70 Jrs. 120 and between 70 and 80 Jrs. 100 HU. Although correlation between calcium salt content and absorption of bone under CT are well known, there are other factors (mainly fatty involution of bone marrow) who influences the absorption behaviour of cancellous bone.