体素内不相干运动成像在食管鳞癌新辅助化疗疗效评估及预测中的应用

Application of intravoxel incoherent motion sequence in evaluating and predicting response to neoadjuvant chemotherapy in esophageal squamous cell carcinoma

目的 探讨体素内不相干运动（IVIM）在食管鳞癌新辅助化疗疗效评估及预测中的价值.方法 前瞻性收集2015年9月至2017年3月经临床及病理证实为食管鳞状细胞癌的47例患者.所有患者均于新辅助化疗前及化疗结束后行MRI常规扫描及IVIM检查,并测量肿瘤的标准ADC、扩散系数（D）、灌注系数（D＊）及灌注分数（f）值.依据实体瘤疗效评价标准（RECIST）1.1版本将患者分为完全缓解（CR）、部分缓解（PR）、稳定（SD）和进展（PD）.化疗后又行手术的患者31例,依据病理标本肿瘤退缩分级（TRG）分为TRG 0～3级,分别为完全缓解、中度缓解、轻度缓解和未缓解.采用配对t检验和独立样本t检验（正态分布）,以及Wilcoxon秩和检验（非正态分布）比较新辅助化疗前与化疗后以及不同疗效的患者间各参数值的差异.差异有统计学意义的参数采用ROC曲线下面积评价参数的诊断效能.结果 47例患者新辅助化疗前后标准ADC值分别为（1.97±0.51）×10-3、（2.42±0.52）×10-3 mm2/s,D值分别为（1.30±0.30）×10-3、（1.63±0.35）×10-3 mm2/s,新辅助化疗后标准ADC值及D值较化疗前明显升高,差异均有统计学意义（t值分别为-6.35、-5.25,P值均〈0.01）,D＊、f值化疗前后差异无统计学意义（P〉0.05）.新辅助化疗后部分缓解者29例,稳定者18例,无完全缓解和进展的患者.化疗前部分缓解患者标准ADC、D、f值均明显低于稳定患者（t值分别为-3.11、-2.53、-2.10,P值均〈0.05）,化疗后部分缓解与稳定患者间各IVIM参数值的差异均无统计学意义.新辅助化疗后又行手术的31例患者中,TRG 2级14例,TRG 3级17例,无TRG 0、1级的患者.化疗前TRG 2与TRG 3级患者间各IVIM参数值的差异均无统计学意义,化疗后TRG 2级和3级患者的D值分别为（1.81±0.31）×10-3、（1.46±0.39）×10-3 mm2/s,差异有统计学意义（t=2.76,P〈0.05）.以D=1.68×10-3 mm2/s评价新辅助化疗疗效的诊断效能最高,敏感度和特异度分别为85.7％和70.6％.结论 IVIM可作为一种评估及预测食管鳞癌新辅助化疗疗效的影像学方法,其中D值是最有价值的参数.

Objective To assess intravoxel incoherent motion（IVIM） in evaluating and predicting response to neoadjuvant ehemotherapy（NAC） in esophageal squamous cell earcinoma（ESCC）. Methods Forty-seven patients with ESCC diagnosed by pathological findings on biopsy from September 2015 to March 2017 were prospectively collected. All patients were examined before and after NAC using routine MRI scan and [VIM, The standard apparent diffusion coefficient （ADC）, diffusion coefficient （D）, perfusion coefficient （D＊） and perfusion score （f） were measured. The patients were divided into complete response （CR）, partial response （PR）, stable disease （SD） and progressive disease （PD） according to the 1.1 version of the response evaluation criteria in solid tumors （RECIST）. Thirty-one patients underwent surgery after NAC, and the patients were divided into TRG 0-3 according to tumor regression grade （TRG）. The differences of parameter values before and after NAC between different groups were analyzed using Student＇s t test （nomlal distribution） and Wilcoxon rank sum tests （non-normal distribution）. The parameters with statistical significance were evaluated by the receiver operating characteristics （ROC） curves. Results The ADC values before and after NAC were （1.97±0.51）× 10-3, （2.42±0.52）× 10-3 mm2/s. The D values before and after NAC were （1.30 ± 0.30） × 10^-3, （1.63 ± 0.35）× 10^-3 mm2 / s. The ADC and D values after NAC were significantly higher than those before NAC, and the differenees were statistieally significant （t=- 6.35, - 5.25 respectively, both P〈0.01）. There were no statistical differences on D and f between before and after NAC （P〉0.05）. The patients were divided into PR group （29 cases） and SD group （18 cases） after NAC, without CR and PD patients. The ADC, D and f values of PR group were significantly lower than those of the SD group before NAC （t= - 3.11, - 2.53 and - 2.10 respectively, all P〈0.05）. The ADC, D, D＊ and f values after NAC revealed no significant difference between PR and SD groups. Thirty-one patients received operation after NAC, which were divided into TRG 2 group （14 eases） and TRG 3 group （17 eases） according to TRG standard, without TRG0 and TRG 1 patients. All the parameter values before NAC revealed no significant difference between TRG 2 and TRG 3 groups. The D values after NAC in TRG 2 and TRG 3 groups were （1.81±0.31）× 10-3, （1.46±0.39）×10-3 mmZ/s respectively, and the significant difference was found between two groups （t=2.76, P〈0.05）. The efficiency of efficacy evaluation for NAC was the highest at D value of 1.68 × 10-3 mm2/s, with sensitivity and specificity being 85.7% and 70.6%, respectively. Conclusion IVIM can be used as a new imaging method to evaluate and predict the efficacy of NAC for ESCC, among which the parameter D was the most valuable.