能谱CT成像在恶性肺结节大小与血含量相关性研究中的应用价值

The Application Value of Spectral CT in Study of Correlation between the Size and the Blood Content of Malignant Lung Nodules

目的：运用宝石能谱CT和GSI浏览器,研究肺癌患者结节大小与血含量的相关性。方法：收集2014年8月至2015年6月在中国医科大学附属第一医院经临床病理证实为肺癌的40例患者,46个结节。按结节大小分为三组：直径≤2 cm的16例、〉2 cm~≤3 cm的15例、〉3 cm的15例。行能谱CT、GSI模式双期扫描,获得能谱系列成像,在肿瘤最大层面测量不同大小结节之间的平均CT值、平均水密度值和平均碘密度值,分别对上述参数进行独立样本单因素方差分析及相关性分析。结果：在能谱模式双期扫描中随着结节体积增大平均碘密度明显降低,直径为≤2 cm、〉2 cm~≤3 cm、〉3 cm结节平均碘密度在动脉期分别为（17.45±4.56）、（12.05±4.89）、（10.31±5.76）（100μg/cm3）,在静脉期分别为（18.32±3.59）、（14.05±4.13）、（12.82±4.58）（100μg/cm3）,直径≤2 cm的结节与另外两组差异均有统计学意义（P〈0.05）。在能谱模式双期扫描中三组之间的平均CT值和平均水密度没有统计学差异（P〉0.05）。平均水密度和平均CT值都受肿块里的气体含量影响,但是平均碘密度不受影响,GGN与实性结节在动脉期平均CT值与平均水密度分别为（-323.83±220.27）、（43.63±15.02）HU,（638.47±227.07）、（1017.27±15.23）（100μg/cm3）。GGN的平均CT值和平均水密度与实性结节相比明显降低,并且有明显统计学差异（P〈0.05）,两者之间动脉期碘密度分别为（12.86±5.92）、（12.70±4.28）（100μg/cm3）没有明显统计学差异。结论：宝石能谱CT可对肺内结节血含量进行定量分析,随着结节体积增大,平均碘密度逐渐降低。平均水密度与平均CT值明显相关,而平均碘密度与平均CT值无明显相关性,运用平均碘密度表示肿块血含量比CT值更准确。

objective： To investigate the relationship between nodules size and blood content in patients with lung tumors by spectral computed tomography and the gemstone spectral imaging（GSI） viewer. Methods： During the period from August 2014 to June 2015, 40 patients with 46 lung nodules were collected in the first hospital of China medical university. The were divided the 46 nodules into three groups based on maximum diameter（small, 2 cm, 16 cases; medium, 2 cm ~ ≤ 3 cm, 15 cases; large, 3 cm, 15, cases）. All patients received biphasic pulmonary enhanced CT scan with GSI mode on a MDCT（Discovery CT 750 HD, GE healthcare）. The region-of-interest was placed on the tumor＇s maximum section, and the mean CT value, water density and iodine density were measured. The difference between the mean values of variables was assessed with one way ANVOA. Pearson＇s product-moment correlation coefficient（r） was used to study the relationship between the CT values and the material densities. Results： The mean value of iodine density was significantly lower in larger tumors. The mean iodine density in arterial phase and venous phase in tumors of ≤ 2 cm, 2 ~ 3 cm, and〉 3 cm were（17.45 ± 4.56）,（12.05 ± 4.89）,（10.31 ± 5.76）（100 μg/cm3）,（18.32 ± 3.59）,（14.05 ± 4.13）,（12.82 ± 4.58）（100 μg/cm3）, respectively. Significant difference in average iodine density was noted between tumors of from 2~3 cm and ≤ 2 cm（P 〈0.05）, and between those of〉 3 cm and ≤ 2 cm（P〈 0.05）. There were no statistically significant differences in mean CT value and water density among three groups. The average CT value and water density were obviously influenced by air, but the average iodine density was unaffected. The average CT value and water density of the GGO-type tumors and solid-type tumors in arterial phase were（-323.83 ± 220.27）,（43.63 ± 15.02）（HU）,（638.47 ± 227.07）,（1 017.27 ± 15.23）（100 μg/cm3）（P〈 0.05）, respectively. The average iodine density of the GGO-type tumors and solid-type tumors were（12.86 ± 5.92）,（12.70 ± 4.28）（100 μg/cm3）（P〉 0.05）, respectively. Conclusion： With the increasing of tumor size, iodine density decreases gradually; The average water density were significantly related with CT value, but the average iodine density and the average CT value were no correlation. So the average iodine density is more accurate to indicate the blood content of tumors than mean CT value.