扩散加权成像表观扩散系数及其相对值测定对直肠癌周围淋巴结定性诊断的价值

摘要

Objective To investigate the diagnostic value of apparent diffusion coefficient (ADC)and relative apparent diffusion coefficient(rADC) values for determining periphery benign and malignant lymph nodes of rectal cancer.Methods Sixty-eight patients with rectal cancer confirmed by colonoscopy underwent routine MRI and DWI.The ADC values of lymph nodes of rectal cancer were measured and the rADC values were calculated.The correlation of ADC values and rADC values between benign and malignant lymph nodes was analyzed.Results According to pathological results,there were 12 benign lymph nodes and 18 malignant lymph nodes.The values of ADC and rADC of benign group were(1.0513 ±0.1284) × 10-3 mm2/s and 0.8756 ±0.1197 respectively,butwere (0.8957 ±0.1608) × 10-3 mm2/s and 0.6832 ±0.1488 respectively in malignant group.There was significant difference(F =7.858,P =0.009;F =13.974,P =0.001)between the two groups.The ROC curve was used to determine ADC and rADC values with lymph nodes as the test variable.When ADC served as a variable value,the AZ area under the ROC curve was 0.769,sensitivity was 75 ％ and specificity was 67.3 ％,all of which were of moderate diagnostic value.When rADC served as the test variable,the area under the ROC curve was 0.824,sensitivity was 91.7％,and specificity was 73.2％,which were higher than those of ADC,but still of moderate diagnostic value.Conclusions ADC values and rADC values are correlated with the benign or malignant pathologic result of lymph nodes of rectal cancer,which can help to improve the accuracy of diagnosis.%目的 探讨扩散加权成像(diffusion weighted imaging,DWI)表观扩散系数(apparent diffusion coefficient,ADC)及相对表观扩散系数(relativeapparent diffusion coefficient,rADC)测定对直肠癌周围淋巴结定性诊断的价值.方法 68例经肠镜诊断的直肠癌患者行常规MRI及DWI扫描,测定直肠癌区域淋巴结的ADC值,并计算rADC值.对良性增生、转移淋巴结ADC值及rADC值进行相关性分析.结果 依照手术病理结果,入组良性增生组共12个,转移组共18个.良性增生组ADC值为(1.0513 ±0.1284) ×10-3 mm2/s,rADC值为0.8756 ±0.1197;转移组ADC值为(0.8957±0.1608)×10-3 mm2/s,rADC值为0.6832±0.1488,两组比较,差异均有统计学意义(F=7.858,P=0.009;F=13.974,P=0.001).把良恶性淋巴结作为变量检验ADC值和rADC值并绘制受试者工作特性曲线(ROC),ADC值为检验变量时,ROC曲线下面积为0.769,诊断价值中等,以0.9682为阈值,其敏感度为75.0％,特异度为67.3％.以rADC值为检验变量,ROC曲线下面积为0.824,较ADC值ROC曲线下面积大,诊断价值中等,以0.7666为阈值,其敏感度91.7％,特异度73.2％.结论 ADC值及rADC值的测量对直肠癌周围区域淋巴结的良恶性鉴别有一定的诊断意义.