低剂量CT灌注成像在进展期胃癌新辅助化疗疗效评价中的价值

The Value of Low-Dose CT Perfusion Imaging in Predicting Efficacy of Neoadjuvant Chemotherapy in Advanced Gastric Cancer

目的探讨低剂量CT灌注成像(LDCTPI)的灌注参数值在进展期胃癌患者新辅助化疗疗效评价中的价值。方法对30例进展期胃癌患者在化疗前后分别进行LDCTPI检查(120 k V,50 m As),并测取肿瘤区CT灌注参数血流量(BF)及血容量(BV)值;所有患者接受化疗(ECF方案)2个疗程,化疗结束后1周内进行手术切除肿瘤,并取得术后病理疗效分级结果;采用配对样本t检验比较BF及BV值在胃癌化疗前后的差异性,使用Spearman检验分析胃癌化疗后BF及BV值减少率与病理疗效分级之间的相关性,再制作受试者工作特征(ROC)曲线,计算曲线下面积(AUC),并找出预测胃癌化疗有效的BF及BV值减少率截值。结果 BF及BV值在胃癌化疗前后均有显著统计学差异(P<0.01),胃癌化疗后BF值减少率及BV值减少率与病理疗效分级均呈显著相关(r=0.660,P=0.000;r=0.706,P=0.000)。如果将BF值下降12.1%(ROC曲线AUC为0.816,P=0.005)作为评价胃癌化疗有效的截值,其敏感度是82%,特异度是84%;将BV值下降32.8%(ROC曲线AUC为0.844,P=0.002)作为评价胃癌化疗有效的截值,其敏感度是82%,特异度是89%。结论 CT灌注参数BF、BV值减少率可以作为预测胃癌化疗疗效的评估指标。

Objective To explore the value of low-dose CT perfusion imaging（ LDCTPI） parameters in predicting efficacy of neoadjuvant chemotherapy（ NAC） for patients with advanced gastric cancer（ AGC）. Methods Thirty patients with AGC were studied prospectively using LDCTPI examinations to measure 2 parameters： blood flow（ BF） and blood volume（ BV） of tumor area before and after chemotherapy,respectively. All of the patients received 2 courses of chemotherapy（ ECF regimen） and resection of tumors within 1 week after chemotherapy,and obtained the results of postoperative pathology. The differences of BF as well as BV values of AGC between before chemotherapy and after chemotherapy were compared by paired-samples t test. The correlations between the decrease in rates of BF as well as BV value after chemotherapy and pathology response grade were analyzed by Spearman statistical test,and ROC curve was used to find the cutoff value of the decreased rates of BF and BV value as evaluation indicators of AGC after NAC and to calculate the area under the curve（ AUC）. Results There were significant differences in BF and BV values of gastric cancer between pre-chemotherapy and post-chemotherapy（ P〈0. 01,respectively）,and there were correlations between the decrease rates of BF as well as BV value of AGC after NAC and pathology response grade（ r = 0. 660,P = 0. 000; r = 0. 706,P = 0. 000,respectively）. If the decrease rate of BF value of 12. 1%（ AUC was 0. 816,P = 0. 005） was used as the cutoff value for chemotherapy effectiveness of AGC,a sensitivity of 82% and specificity of 84% were achieved. If the decrease rate of BV value of 32. 8%（ AUC was 0. 844,P = 0. 002） was used as the cutoff value for chemotherapy effectiveness of AGC,a sensitivity of 82% and specificity of 89% were achieved. Conclusion The decrease rates of BF and BV value may be evaluation indicators in predicting the efficacy of chemotherapy in AGC.