摘要目的 探讨采用CT能谱成像评价阿西替尼治疗兔VX2肝肿瘤的效果价值.方法 将32只VX2肝癌模型肿瘤种植成功、肿瘤直径为1.0~2.5 cm的存活瘤兔纳入研究,按照电脑随机数字法分为实验组和对照组,每组16只,分别经胃管灌食阿西替尼和生理盐水治疗.采用能谱CT机于治疗前和治疗后第2天、第4天、第7天、第10天和第14天,分别对实验组和对照组瘤兔行上腹部CT平扫和动脉期、静脉期增强扫描.测量各时间点肿瘤大小(TS),计算TS变化百分比(ΔTS);测量计算全肿瘤、肿瘤边缘强化区和肿瘤中心区标准化碘浓度(NIC)和标准化碘浓度差(NICD).分别在第7天和第14天完成CT检查后,采用电脑随机数字法选取实验组和对照组各8只兔行病理检查,记录微血管密度(MVD).采用Mann-Whitney U检验比较实验组和对照组间ΔTS及NICD的差异,Wilcoxon符号秩检验评价治疗后不同时间点间NICD的差异,Spearman相关性分析评价实验组治疗后各时间点肿瘤NICD与第14天肿瘤ΔTS间、治疗后第7天和第14天各部位NIC和MVD间的相关性.结果 治疗后对照组和实验组的ΔTS持续增大,治疗后第7天、第10天和第14天,实验组的ΔTS小于对照组,差异有统计学意义(P<0.05).各时间点间的NICD比较,对照组、实验组不同部位的NICD差异均无统计学意义(P均>0.05).治疗后第2天,实验组各ROI的NICD均小于对照组(P<0.05);治疗后第4、7、10、14天,实验组部分扫描期相和部位的NICD小于对照组,差异有统计学意义(P<0.05).治疗后第14天实验组ΔTS为(41.44±5.48)%.治疗后第2天全瘤动脉期、全瘤静脉期、肿瘤边缘强化区动脉期NICD与第14天ΔTS呈正相关(r值分别为0.692、0.521和0.639,P值分别为0.002、0.032和0.005).治疗后第14天肿瘤边缘强化区动脉期NICD与ΔTS呈正相关(r=0.673,P=0.003).实验组治疗后第7天和第14天全瘤动脉期和静脉期、肿瘤边缘强化区动脉期和静脉期、肿瘤中心区动脉期NIC和MVD具有相关性(r值为-0.69~0.72,P<0.05);肿瘤中心区静脉期NIC和MVD无相关性(P>0.05).结论 CT能谱成像可用于兔VX2肝肿瘤阿西替尼治疗后的疗效评估和早期预测.

abstractsObjective To evaluate the CT spectral imaging in assessing the therapeutic efficacy of axitinib in rabbit VX2 liver tumors. Methods Thirty-two VX2 liver tumor-bearing rabbits (diameter 1.0 to 2.5 cm) were prospectively and randomly assigned into the study group (axitinib treated group, n=16) or the control group (pseudo-therapy group, n=16). They were treated with axitinib or saline by using the gastric tube respectively. All the rabbits underwent unenhanced, arterial-phase (AP) and portal-phase (PP) contrast enhanced CT examinations by using spectral CT at different time points (baseline, 2, 4, 7, 10 and 14 days after treatment). Tumor size (TS) at each time point was recorded to calculate the percentage change (ΔTS)after treatment relative to baseline. Iodine concentration (IC) of the entire tumor, the peripheral hypervascular region and the center of the tumor were measured and normalized to aorta (NIC) to generate the difference for the NIC (NICD) between a given time and baseline. The tumorΔTS and NICD between the control and treated groups were compared by using Mann-Whitney U test. Serial changes in NICD at different time points were evaluated by using Wilcoxon signed rank test. Correlations between the NICD andΔTS, between NIC and microvessel density (MVD) were analyzed. Results The tumorΔTS after treatment in the control group and study group increased continuously. The tumorΔTS was significantly smaller in the treated group than that in the control group at day 7, 10 and 14. At day 2 , 4 and 10 after treatment, each tumor NICD in the study group was smaller compared with the control group(P<0.05)except the NICD in the entire tumor and the center of the tumor in AP at day 4 , in the entire tumor in PP and the peripheral hypervascular region of the tumor in AP at day 10; no significant differences were found between the two groups at day 7 and day 14 except the NICD in the entire tumor in PP. The tumor ΔTS at day 14 after treatment was (41.44 ± 5.48) %. The tumor NICD in the entire tumor at day 2 in the two phases and the peripheral hypervascular region of the tumor in AP were positively correlated with ΔTS at day 14 (r=0.692, 0.521 and 0.639, P=0.002, 0.032 and 0.005, respectively). The tumor NICD in the peripheral hypervascular region of the tumor in AP were positively correlated with ΔTS at day 14(r=0.673,P=0.003). The tumor NIC values in the entire tumor, peripheral hypervascular region and the center of the tumor in the two phases at day 7 and day 14 had positive correlations with MVD (r=-0.69 to 0.72, all P values<0.05) except the NICD in the center of the tumor in PP (P>0.05).Conclusion CT spectral imaging allows the evaluation and early prediction of tumor response to axitinib in rabbit VX2 liver tumors.