能谱技术在肺结节CT值定量测量中的实验研究  

Experimental study on quantitative measurement of CT attenuations of pulmonary Nodules with gemstone spectral imaging

作　　者：方亚军[1] 黄召勤[1] 凌春香[1] 冯吉贞[1] 韩雪[1] 曹会志 刘庆伟[1] 路怀英[1] 

机构地区：[1]山东大学附属省立医院医学影像科,山东济南250000 [2]GE中国CT影像研究中心

出　　处：《实用放射学杂志》2012年第3期454-457,共4页Journal of Practical Radiology

基　　金：山东省自然科学基金资助项目（编号：Y2008C108）.

摘　　要：目的 通过对肺结节模型进行宝石能谱成像（gemstone spectral imaging,GSI）扫描,探讨单能成像在肺结节CT值准确测量中的价值.方法 制作3个直径为20 mm的球体模拟肺结节,结节分别由3种密度不同的物质制成（聚丙烯,尼龙,腈纶）,相应CT值分别为-100 HU、60 HU、100 HU.结节固定在塑料肺基底模型（-900 HU）内,周围加基液或基液加动物骨骼以改变模型周围环境.Discovery CT750 HD能谱CT对肺结节模型进行GSI扫描和常规扫描（混合能量）.GSI扫描参数：140 kV/80 kV瞬时切换;630 mA;层厚64×0.625 mm;螺距0.5161;SFOV 50 cm;DFOV 38 cm.常规扫描管电压120 kV,管电流（mA）根据GSI扫描患者的CT剂量指数确定,其他扫描参数与GSI扫描一致.3位经验丰富的影像学医师独立测量不同扫描条件下结节的CT值及标准差值.混合能量和单能条件下所得结节的CT值及相应的图像信噪比（SNR）进行比较.结果 （1）分别在基液与基液＋骨骼条件下对肺结节模型进行GSI扫描：所得CT值均无明显统计学差异（P＞0.05）.所有结节转速为0.8 s/r及60 HU结节转速为1.0 s/r时SNR无明显统计学差异（P＞0.05）;其他条件下SNR间差别有统计学意义（P＜0.05）.（2）分别在基液与基液＋骨骼条件下对肺结节模型进行常规扫描：所得CT值间差别有统计学意义（P＜0.05）.所有SNR间差别亦有统计学意义（P＜0.05）.结论 GSI扫描可有效减除硬化伪影对CT值的影响得到较常规扫描更准确的肺结节CT值;相应SNR亦较常规扫描趋于稳定.Objective To evaluate the value of gemstone spectral imaging（GIS） in accurate measurement of （TT attenuations of pulmonary nodules with Discovery CT750 HD. Methods 3 simulated spherical pulmonary nodules with 20 mm in diameter were made with three different kinds of materials （ Polypropylene, Monomer casting nylon and ACRYLIC ） ,each material was applied to represent different density （ 100HU,60HU and 100 HU ） . All nodules were set at a plastic hmg phantom （ -900 HU ） . Phantom was fixed in a container filled with fluid, muscle and bone to simulate thorax. The phantom was scanned under both single ener gy （SE） and mixed energy （ME） CT techniques. Scans were performed with Discovery CT750 HD scanner using GSI technique （GSI kV; 630 mA; 64×0.625 mm slices; 0.516 ： 1 pitch; 50 cm scan field of view; 38 cmdisplay field of view ） with there different ratation time （ 0.5 s,0.8 s,1.0 s ） . In addition, images were generated using the high resolution 120 kV technique （ convert mA according to GSI CTDI, other parameters were the same with SECT） . Scans were performed with and without the added hone. Quantitative CT numbers and standard deviation numbers of nodules at different scanning conditions were measured by three experi enced radiologists on the workstation. CT numbers and signal to noise ratio（SNR） of each nodule under different SECT and MECT were compared. Results （1）The phantom scanned under SE in Nacl＋Model or Nacl＋ Model ＋Bone with Discovery CT750 HD showed ： All CT numbers did not show significant difference （P〉0.05） . In eonditions of （0.8 s, rotation time ） and （1.0 s, rotation time ; 60 HU , density ） , the SNR did non show significant difference（P〉0.05 ） , the other conditions the SNR showed significant difference （P〈0.05）. （2）The phantom scanned under ME in Nacl＋Model or Nacl＋ Model ＋ Bone with Discovcry CT750 HD showed.all CT numbers showed significant difference （P〈0.05 ） , all the SNR also showed signi

关 键 词：肺 肺结节 宝石能谱成像 体层摄影术 X线计算机 实验 

分 类 号：R322.35[医药卫生—人体解剖和组织胚胎学] R814.42[医药卫生—基础医学]