DXA测量BMD与超声测量SOS的比较

目的　本文通过对同一个人的跟骨超声声速(SOS)测量与双能X线吸收法测量腰2-4，股骨近端骨密度(BMD)的临床对比来评价超声骨密度仪测量跟骨的SOS对诊断骨质疏松症的敏感性和与DXA测量BMD的相关性。方法　对523名8～87岁健康人群同时采用DXA测量L2-4，股骨近端(Neck,Ward三角，Troch)BMD和超声骨密度仪测量左跟骨SOS值并进行相关分析。对1006名3～87岁健康人群测量左右跟骨的SOS值。结果　SOS与DXA测量BMD的骨峰值(PBM)均出现在20～39岁，SOS的PBM男性为(1542.83±27.44)m/s，女性为(1531.02±29.96)m/s。40岁以后随着年龄的增加，二者均逐渐下降。健康成人中BMD与SOS的相关系数为0.3～0.6，骨质疏松患者BMD与SOS的相关系数(r=0.16～0.39)较健康人(r=0.33～0.61)低。左右足跟SOS无显著差异，DXA的BMD与SOS诊断骨质疏松症(OP)的符合率为60%。结论　DXA测量BMD与超声SOS为中等相关。建议在单独使用超声骨密度仪测量SOS来诊断OP时，应当参照临床症状和X线的检查全面考虑，以免造成漏诊或误诊。

Comparison between SOS ofquantitative ultrasound and BMD meas ured by DXA in diagnostic value of osteoporosis

Dual energy x-ray absorptiometry(DXA) is a method o f measur ing the material properties of bone, that is, bone mineral density(BMD), whereas the quantitative ultrasound(QUS) is a method of assessing the mechanical proper ties of bone by the reflection and attenuation of ultrasound. We evaluated the s ensitivity of ultrasound in measuring bone mass by comparing with dual energy x -ray absorptiometry. BMD at lumbar spine and proximal part of the femur was mea sured by DXA and SOS at calcaneus by QUS in 892 subjects of 3 to 87 years in Chengdu. The results showed that SOS peaked at the age of 20 and declined with aging. The peak SOS was (1542.83±27.44)m/s in males and (1531.02±28.96)m/s in females. The correlation coefficients between SOS and BMD were 0.12～0.21 in children and 0.3～0.6 in adults, respectively. The homogeneity rate of the diagnosis of osteoporosis was 60% between DXA and QUS. It was concluded that QUS is used mainly for determining change in bone mass and structure, and DXA mainly for determining change in bone mass; so it had better to use the two methods s imultaneously to diagnose osteoporosis and predict the risk of fracture due to o steoporosis.