不同的ADC值对直肠癌患者新辅助放化疗后淋巴结转移的评估价值

The Vaule of Various Apparent Diffusion Coefficient Parameters in the Diagnosis of Rectal Cancer after Neoadjuvant Chemoradiotherapy

目的探讨不同ADC值在局部进展期直肠癌(LARC)患者新辅助放化疗(nCRT)后淋巴结转移诊断价值。方法回顾性纳入65例LARC患者,根据术后病理淋巴结状态,分为有淋巴结转移组和无淋巴结转移组。两名不同年资的影像诊断医师采用容积感兴趣区(ROI)勾画法分别测得nCRT前后ADC的最大值、最小值、均值、差值(最大值与最小值之差),并计算nCRT前后ADC最大值差(治疗后ADC最大值与治疗前ADC最大值之差)、最小值差(治疗后ADC最小值与治疗前ADC最小值之差)、均值差(治疗后ADC均值与治疗前ADC均值之差)以及最大值变化率(ADC最大值差/治疗前ADC最大值)、最小值变化率(ADC最小值差/治疗前ADC最小值)、均值变化率(ADC均值差/治疗前ADC均值)。分析上述不同的ADC值在nCRT后有无淋巴结转移中的差异,绘制受试者工作特征曲线(ROC)明确各ADC值预测直肠癌nCRT后淋巴结转移的诊断效能。结果14个不同ADC参数值的组间一致性较好,组内相关系数(ICC)值为0.408~0.886。nCRT后ADC最大值、ADC最小值、ADC均值、治疗前后ADC最大值差、治疗前后ADC最小值差、nCRT前后ADC均值差、ADC最大值变化率、ADC最小值变化率和ADC均值变化率与nCRT后淋巴结转移有相关性(r=-0.272~-0.434)。nCRT后ADC最大值、ADC最小值、ADC均值、治疗前后ADC最大值差、治疗前后ADC最小值差、nCRT前后ADC均值差、ADC最大值变化率、ADC最小值变化率和ADC均值变化率在nCRT后有淋巴结转移组和无淋巴结转移组中差异具有统计学意义(P=0.001~0.03)。其中nCRT后ADC均值、ADC均值差在区分有无淋巴结转移的诊断效能最好,曲线下面积(AUC)分别为0.740、0.753。结论不同ADC值在一定程度上反映直肠癌nCRT后淋巴结状态,测量nCRT后直肠肿瘤ADC均值对nCRT后淋巴结状态进行评估更加方便、准确。

Objective To investigate the significance of different apparent diffusion coefficient(ADC)parameters in the diagnosis of lymph node metastasis in patients with locally advanced rectal cancer(LARC)after Neoadjuvant chemora⁃diotherapy(nCRT).Methods 65 patients with LARC were retrospectively included.According to postoperative pathologi⁃cal lymph node status,they were divided into the group without lymph node metastasis and the group with lymph node me⁃tastasis.The maximum ADC value,minimum ADC value,mean ADC value and difference of ADC value(difference between maximum ADC value and minimum ADC value)before and after nCRT were measured by two imaging diagnostic physicians with different seniority using volume ROI mapping method.Then calculate the maximum difference of ADC value(the difference between the maximum value of ADC after treatment and the maximum ADC value before treatment),the minimum difference of ADC value(the difference between the minimum ADC after treatment and the minimum ADC before treat⁃ment),the mean difference of ADC value(the difference between the mean ADC after treatment and the mean ADC before treatment),variation rate of maximum ADC value(maximum difference/ADC maximum before treatment),variation rate of minimum ADC value(minimum difference/ADC minimum before treatment),and variation rate of mean ADC value(mean difference/ADC mean before treatment).Analyze the differences of the above different ADC values between the group with⁃out lymph node metastasis and the group with lymph node metastasis.ROC curves were drawn for ADC values with statistical significance,Areas under the receiver operating characteristic curves(AUC)were calculated to evaluate diagnostic perform⁃ance of each ADC value for lymph node metastasis after nCRT for rectal cancer.Results The intra⁃observer agreement of the14 ADC values were good(ICC:0.408-0.886).The maximum ADCvalue after treatment,minimum ADC value after treatment,mean ADC value after nCRT,maximum difference of ADC value,minimum difference of ADC value,mean differ⁃ence of ADC value,maximum variation rate of ADC value,minimum variation rate of ADC value,and mean variation rate of ADC value were correlated with lymph node metastasis(r=-0.272--0.434).There were statistically significant differ⁃ences between the mean ADC value before and after nCRT,the minimum ADC value after nCRT,the maximum difference of ADC value,the mean difference of ADC value,variation rate of maximum ADC value,variation rate of minimum ADC value and variation rate of mean ADC value between the group without lymph node metastasis and the group with lymph node me⁃tastasis after nCRT(P=0.001-0.03).Among them,the mean ADC value after nCRT(AUC=0.740),and the mean difference of ADC value(AUC=0.753)had the best diagnostic efficacy in distinguishing lymph node metastasis.Conclu⁃sion Different ADC values can reflect lymph node status after nCRT for rectal cancer,and it is more convenient and accu⁃rate to measure the mean value of ADC of rectal tumor after nCRT to evaluate lymph node status after nCRT.