基于欧洲体模的宝石CT能谱成像的骨密度测量参数优化

Optimization of bone density measurement parameters by gemstone CT energy spectrum imaging based on european body model

目的探讨使用宝石能谱CT测量骨密度的最佳扫描参数。方法选取编号145号欧洲腰椎体模,将松质骨羟基磷灰石(HAP)含量分别为50、100、200 mg/cm 3的三个椎体标记为L1、L2、L3,使用宝石能谱CT配置的14组扫描参数对欧洲体模进行重复10次扫描,选择HAP-H 2O基物质对测量HAP含量。将不同扫描条件测的测量值分别与体模实际值使用单样本t检验进行比较。结果在测量L1椎体时,0.7 s 260 mA组、0.8 s 260 mA组、0.5 s 630 mA组、0.6 s 640 mA组的测量值与椎体实际值差异无统计学意义;在测量L2椎体时,仅有0.8 s 260 mA组、0.5 s 630 mA组、0.6 s 640 mA组的测量值与椎体实际值差异无统计学意义;所有条件测量L3椎体,测量值与椎体实际值差异均有统计学意义(P<0.05)。结论CT能谱成像可以对欧洲体模的HAP值进行精确的定量测量,但可能存在某个取值范围,超过该范围可能会出现测量结果的偏移。综合考虑辐射剂量的因素,使用宝石能谱CT测量骨密度时,推荐采用0.8 s 260 mA这一条件进行扫描。

Objective To explore the best scanning parameters for bone mineral density(BMD)measurements by gemstone energy spectrum CT.Methods Within the European spine phantom(ESP)Number 145,3 vertebral bodies with hydroxyapatite(HAP)content of 50,100,and 200 mg/cm 3 in cancellous bone were labeled as L1,L2,and L3,respectively.The 14 groups of scanning parameters configured by gemstone energy spectrum CT were used to repeatedly scan the ESP for 10 times,and the HAP-H2O based substances were selected to measure the HAP content.The measured values obtained under different scanning conditions were compared with the actual values of the ESP,using the one-sample t test.Results The measured values in the 0.7 s 260 mA group,0.8 s 260 mA group,0.5 s 630 mA group,and 0.6 s 640 mA group were not significantly different from the actual ESP values for the L1 vertebral body.In contrast,the measured values in the 0.8 s 260 mA group,0.5 s 630 mA group,and 0.6 s 640 mA group were not significantly different from the actual ESP values for the L2 vertebral body.However,the measured values at all the parameters were significantly different from the actual ESP values for the L3 vertebral body(P<0.05).Conclusion CT energy spectrum imaging can accurately and quantitatively measure the HAP value of ESP.However,there could be a certain value range,beyond which t deviation of measurements may occur.When comprehensively consider the radiation dose,it is recommended to adopt the condition of 0.8 s 260 mA for the measurement of bone density when using gem energy spectrum CT.