Research of technology in bone mineral density measurement with QCT

Objective Through analysis of clinical data,to research the technique of positioning,scanning and image measurement of bone mineral density with QCT,to study the change regularities of bone mineral density(BMD)in cancellous bone and whole body of lumber vertebrae;to find the relationship between age and BMD of lumber vertebrae;to evaluate the value of these data in clinical diagnosis.Methods Appling the systematic helical CT scanner,the hydroxyapatite phantom,the software of bone mineral densitometry with QCT,to scan and measure the L_2-L_4 of 1586 cases in recent 3 years in our hospital.Result ① To obtain the means and standard deviation(SD)of BMD of L_2-L_4 in every age group.To calculate the ratio of BMD between cancellous bone and whole body of lumber vertebrae.② To obtain the peak value of mean BMD of L_2-L_4 of local male and female residents.It is(177.13±33.75)mg/cm3 in cancellous bone of men,(205.59±36.71)mg/cm3 in whole vertebrae of men,(188.67±38.35)mg/cm3 in cancellous bone of women,(216.39±38.82)mg/cm3 in whole vertebrae of women.③ To compare the morbidity of opteopenia and osteoporosis in people of 40-59 years old according to the different grade scale of diagnosis.If we take the scale of lower than BPV-20%,the rate of opteopenia and osteoporosis are 0.46(cancellous bone of men),0.31(whole body bone of men);0.40(cancellous bone of women),0.38(whole vertebrae of women).Conclusions ① The trend of change are similar between BMD of cancellous bone and whole vertebrae in men and women.The BMD decreases as the age increases.② The peak values of BMD of cancellous bone and whole vertebrae in men are a little lower than women.③ The ratio of BMD between cancellous bone and whole vertebrae of lumber decreases as the age increases,that means the lost speed of cortical bone is slower than cancellous bone.④The result of analysis of the morbidity of opteopenia and osteoporosis prompts that the following grade scale of diagnosis are suitable:to take the peak value-20% as level of osteopenia,the peak value-40% as level of osteoporosis.