能谱CT在非小细胞肺癌立体定向放疗预处理评估中的应用价值

The value of spectral CT in the pretreatment evaluation of stereotactic radiotherapy for non-small cell lung cancer

目的探讨能谱CT在非小细胞肺癌(NSCLC)立体定向放疗预处理评估中的应用价值。方法选取2015年6月至2017年12月于山东省千佛山医院医学影像科行宝石能谱CT扫描的非小细胞肺癌患者,共50例(腺癌34例,鳞癌15例,大细胞未分化癌1例)。设定肿瘤给定空间位置感兴趣区,测得肿瘤内碘浓度,采用两独立样本t检验,比较不同病理类型、不同空气含量(实体型肿瘤44例,磨玻璃影型肿瘤6例)肺肿瘤碘浓度的差异。按肿瘤最大直径(d)分为3组:d≤2 cm组(n=18)、2<d≤3 cm组(n=12)和d>3 cm组(n=20),采用单因素方差分析比较3组间碘浓度差异,并采用Spearman相关系数分析碘浓度与肿瘤最大直径的关系。结果肺腺癌组与鳞癌组碘浓度[(21. 71±4. 12)×100 mg/L,(21. 29±3. 93)×100 mg/L]比较,差异无统计学意义(t=0. 24,P>0. 05)。实体型肿瘤组与磨玻璃影型肿瘤组碘浓度[(19. 81±6. 89)×100 mg/L,(18. 27±3. 01)×100 mg/L]比较,差异无统计学意义(t=0. 54,P>0. 05)。d≤2 cm组、2<d≤3 cm组及d>3 cm组的碘浓度分别为(23. 12±5. 35)×100 mg/L,(19. 10±3. 33)×100 mg/L,(13. 90±5. 99)×100 mg/L,3组间比较差异具有统计学意义(F=14. 62,P <0. 01)。肿瘤直径与肿瘤内碘浓度呈负相关(r=-0. 71,P <0. 05)。结论随着肿瘤增大,肿瘤内碘浓度降低,可能与肿瘤的相对血容量降低有关。碘浓度可能是对肿瘤内缺氧细胞群产生放射治疗抵抗作用的一种非侵入性的定量评估,在一定程度上可提示肿瘤放射治疗的预后情况。

Objective To explore the value of Gemstone spectral CT in the evaluation of stereotactic radiotherapy pretreatment in patients with non-small cell lung cancer(NSCLC).Methods Fifty patients with NSCLC(34 cases of adenocarcinoma,15 cases of squamous cell carcinoma,and 1case of large cell undifferentiated carcinoma)who underwent Gemstone spectral CT scan at the department of Medical Imaging of Shandong Provincial Qianfoshan Hospital from June 2015 to December 2017 were selected.The region-of-interest for a given spatial placement of the tumors was set.The iodine density in the arterial phase and the maximum diameter of the tumor were measured.T test for two independent samples was used to compare the differences of iodine density in tumors with different pathological types and different air contents(44 cases of solid tumors,6 cases of ground-glass opacity).The cases were divided into 3 groups according to the tumor maximum diameter(d):d≤2 cm group(n=18),2<d≤3 cm group(n=12)and d>3 cm group(n=20).The differences of iodine density between the three groups were compared and they were separately compared by one-way ANOVA.Spearman correlation was used to analyze the relationship between iodine density and tumor maximum diameter.Results There was no significant difference in the iodine density between adenocarcinoma and squamous cell carcinoma[(21.71±4.12)×100 mg/L,(21.29±3.93)×100 mg/L,t=0.24,P>0.05].And there was no significant difference in the iodine density between solid tumors and ground-glass opacity[(19.81±6.89)×100 mg/L,(18.27±3.01)×100 mg/L,t=0.54,P>0.05].The iodine density of d≤2 cm group,2<d≤3 cm group and d>3 cm group were(23.12±5.35)×100 mg/L,(19.10±3.33)×100 mg/L,(13.90±5.99)×100 mg/L,respectively.The difference between three groups was statistically significant(F=14.62,P<0.01).With the size of tumor increased,the iodine density decreased significantly(r=-0.71,P<0.05).Conclusions With the tumor enlarges,the iodine density in the tumor decreases,which may be related to the relatively decreased blood volume of the tumor.The iodine density may be a non-invasive and quantitative assessment of the radio-resistance ascribable to the hypoxic cell population in a tumor,which may indicate the prognosis of radiotherapy to some extent.