MRI在评估直肠癌局部淋巴结转移中的应用价值

The application value of MRI in the diagnosis of regional lymph node metastasis in rectal cancer

目的:分析直肠癌区域淋巴结的MRI影像学表现,评价MRI在评估直肠癌局部淋巴结转移中的应用价值。方法:回顾性分析2015年5—12月经手术治疗并经病理证实的94例直肠癌患者的MRI图像,观察并记录目标淋巴结的短径、边界、信号、ADC值及周围脂肪信号,以病理诊断转移淋巴结阳性为标准进行分组。对转移淋巴结和非转移淋巴结的边界、信号、周围脂肪信号进行卡方检验,短径和ADC值进行t检验。对有统计学意义的诊断指标进行多因素Logistic回归分析,并利用受试者工作特性(ROC)曲线评价诊断价值。结果:转移淋巴结与非转移淋巴结边界、信号及周围脂肪信号有统计学意义(P<0.05),转移淋巴结和非转移淋巴结的短径分别为(6.25±2.25)mm和(4.80±1.38)mm,两者比较差异有统计学意义(P<0.05)。多因素Logistic回归分析显示淋巴结短径、边界、信号、周围脂肪信号有统计学意义(P<0.05)。ROC曲线显示淋巴结边界诊断价值最高,其次为周围脂肪信号、信号和短径,曲线下面积(AUC)分别为0.815、0.798、0.770、0.710。结论:综合分析直肠周围淋巴结短径、边界、信号特点及周围脂肪信号对诊断转移淋巴结有较大作用,其中边缘、周围脂肪信号的作用最为显著,信号、短径也有助于提高诊断。

Objective： To evaluate the application of MRI in the diagnosis of regional lymph node metastasis in rectal cancer. Methods： During the period from May to December 2015, 94 patients with pathologically-proved rectal underwent MRI were included. The clinical data were retrospectively analyzed. The short-axis diameter, margin, signal and ADC values of the target node and the signal of perirectal fat were observed and recorded. Patients were assigned to the malignant node or benign node group according to pathological analysis. Chi-square （X2） trend test was used to test the margin, signal and the signal of perirectal fat of metastasizing lymph nodes and nonmetastasizing lymph nodes, short-axis diameter and ADC values were compared using the t-test. Multivariate analysis to determine independent significant individual variables by multiple Logistic regression analysis. ROC curve analysis was done to evaluate the diagnostic efficiency. Results： The margin, signal of lymph nodes and signal of perrectal fat showed correlation with the lymph node metastasis（P〈0.05）. The short-axis diameter of metastatic nodes and non-metastatic nodes was （6.25±2.25） mm and （4.80±1.38）mm respectively, the differences between the two groups were significant （P〈0.05）. The short-axis diameter, margin, signal and the signal of perirectal fat were proved to be significant independent predictors of lymph node metastasis by Logistic regression analysis. The AUC value showed that margin carried the highest credibility for the diagnosis of lymph node metastasis, and the next were the signal of perirectal fat and signal. Conclusion： It was helpful to improve the diagnosis of lymph node metastasis by considering the short-axis diameter, margin and signal of the lymph nodes and the signal of perirectal fat, especially the margin and the signal of perirectal fat.