采用CT能谱成像测量体模骨密度的精密度及准确度  

Assessment of precision and accuracy of bone mineral measurement by using spectral CT imaging：phantom study

作　　者：苏永彬[1] 许玉峰[2] 程晓光[1] 董健[2] 王玲[1] 王霄英[2] 曹琪[3] 彭芸[3] 

机构地区：[1]北京积水潭医院放射科,100035 [2]北京大学第一医院医学影像科 [3]首都医科大学附属北京儿童医院影像中心

出　　处：《中华放射学杂志》2014年第11期923-925,共3页Chinese Journal of Radiology

基　　金：北京市卫生系统高层次卫生技术人才培养项目（2009-2-03）

摘　　要：目的 探讨采用CT能谱成像测量体模骨密度的精密度及准确度.方法 体模采用编号145欧洲腰椎体模,包含3个松质骨密度不等的椎体,由上至下分别记为L1、L2、L3,3个椎体的松质骨羟基磷灰石（HAP）含量分别为50、100和200 mg/cm3.对上述体模行能谱CT成像,相同条件下重复扫描10次,基物质对为HAP-水和HAP-脂肪.测量HAP含量,并计算相对标准偏差（RSD）和测量相对误差（RE）.HAP含量能谱CT检查测量值同实际值的比较采用单样本t检验,各椎体在不同基物质对下测量值的比较采用配对t检验.结果 采用HAP-水基物质对时,测得L1、L2和L3的HAP含量分别为（54.5±4.2）、（113.3±2.7）和（219.7±7.7） mg/cm3,与实际值（分别为50.0、100.0和200.0 mg/cm3）的差异均有统计学意义（t值分别为3.400、15.874和8.155,P均＜0.01）;RSD分别为7.67％、2.34％和3.48％;RE分别为5.3％、12.9％和9.8％.采用HAP-脂肪基物质对时,测得L1、L2和L3的HAP含量分别为（91.9±4.0）、（149.5±2.5）和（254.2±7.2） mg/cm3,与实际值的差异均有统计学意义（t值分别为33.498、62.399和23.578,P值均＜0.01）;RSD分别为4.31％、1.68％和2.86％;RE分别为81.0％、49.1％和27.0％.各椎体采用HAP-脂肪基物质测得值高于HAP-水基物质值,差异均有统计学意义（P均＜0.01）.结论 应用CT能谱成像测量骨密度的精密度与准确度均较差,尚不适用于临床应用.Objective To assess the precision and accuracy of bone mineral measurement utilizing spectral CT imaging with a European Spine Phantom （ESP）.Methods Within the ESP named Num.145,there are three orderly vertebral bodies which were marked by L1 with Hydroxyapatite（HAP）of 50.0 mg/cm3,L2 with HAP of 100.0 mg/cm3,and L3 with HAP of 200.0 mg/cm3.The ESP was scanned by using gemstone spectral imaging （GSI） model ten times.Using GSI viewer,measurements of HAP-water concentration and HAP-fat concentration were done.The precision and accuracy of each parameter were evaluated by the results of relative standard deviation （RSD） and relative error （RE）,respectively.The difference between each parameter with the real value was evaluated statistically by one-sample t test.The differences among the three vertebral bodies＇ same parameter were evaluated statistically by paired t test.Results The results of HAP-water concentration in L1,L2,L3 were （54.5 ±4.2）,（113.3 ± 2.7） and （219.7 ± 7.7） mg/cm3,each of which was significantly higher than the real value（t values were 3.400,15.874 and 8.155,P〈0.01）.And,the RSD values were 7.67%,2.34% and 3.48%;the RE values were 5.3%,12.9% and 9.8%.The results of HAP-fat concentration in L1,L2,L3 were （91.9±4.0）,（149.5±2.5） and （254.2±7.2） mg/cm3,each of which was significantly higher than the real value（t values were 33.489,62.399 and 23.578,P〈0.01）.And the RSD values were 4.31%,1.68% and 2.86%; the RE values were 81.0%,49.1% and 27.0%.In every vertebral body,the result of HAP-water concentration was significantly lower than the result of HAP-fat concentration （P〈0.01）.Conclusions By utilizing spectral CT imaging,the precision and accuracy of bone mineral measurement were poor.Therefore,this method is not applicable for clinical measurement.

关 键 词：骨密度 体层摄影术 X线计算机 对比研究 

分 类 号：R816.8[医药卫生—放射医学]