QCT骨密度测量技术的探讨

Research of technology in bone mineral density measurement with QCT

目的通过临床资料分析,对QCT骨密度测量中的扫描定位、图像测量等技术问题进行探讨,对椎体松质骨与整体骨的密度变化进行分析,找出规律。方法采用全身螺旋CT扫描机,羟磷灰石体模,QCT骨密度测量系统软件。研究对象为近3年我院体检和检查对象,共1586例(男712例,女874例)。结果①得出了男、女L2～L4平均骨密度的各年龄组均值和标准差,计算了各年龄组腰椎的松质/整体骨密度比值。②根据20～34岁年龄组的资料,获得本地区男、女L2～L4的骨峰值:男性松质骨:(177.13±33.75)mg/cm3,整体骨:(205.59±36.71)mg/cm3;女性松质骨:(188.67±38.35)mg/cm3,整体骨:(216.39±38.82)mg/cm3。③根据两种分级标准(峰值-13%和峰值-20%)比较了40～59岁年龄组人群的腰椎骨量减少的患病率。结论①男、女L2～L4松质骨与整体骨的密度变化规律基本相同,均随年龄增大而降低。②男性腰椎松质骨与整体骨的骨峰值略低于女性。③腰椎的松质/整体骨密度比值随年龄增长而减小,说明皮质骨密度降低速度低于松质骨。④根据40～59岁年龄组人群的腰椎骨量减少的患病率的比较,认为采用骨峰值-20%和骨峰值-40%作为骨量减少和骨质疏松的诊断指标更合理。

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 L2-L4 of 1586 cases in recent 3 years in our hospital. Result ① To obtain the means and standard deviation（SD） of BMD of L2-L4 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 L2-L4 of local male and female residents. It is （177.13 ± 33.75） mg/cm^3 in cancellous bone of men, （205.59 ± 36.71 ） mg/cm^3 in whole vertebrae of men, （ 188.67 ± 38.35） mg/cm^3 in cancellous bone of women, （216.39 ± 38.82） mg/cm^3 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 osteoporesis 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.