3.0T MR多b值DWI对鼻咽癌患者颈部良恶性淋巴结的鉴别诊断价值

目的探讨3.0T磁共振多b值扩散加权成像(DWI)对鼻咽癌患者颈部良恶性淋巴结的鉴别和诊断价值。方法收集本院66例鼻咽癌患者的临床资料,并以35例良性淋巴结肿大患者为对照。所有患者均行MR常规平扫、增强和多b值DWI影像学检查,比较不同b值下鼻咽癌患者原发灶、颈部转移性小淋巴结、转移性大淋巴结与良性淋巴结肿大患者表观扩散系数(ADC)值的差异。通过绘制受试者工作特征(ROC)曲线计算诊断阈值、ROC曲线下面积、敏感度和特异度,评价不同b值下ADC值对鼻咽癌颈部良恶性淋巴结的鉴别和诊断价值。结果随着b值的增加,鼻咽癌患者原发灶、颈部转移性小淋巴结、转移性大淋巴结与良性淋巴结肿大患者ADC值呈现减少的趋势;鼻咽癌患者原发灶、颈部转移性小淋巴结、转移性大淋巴结之间ADC值的比较,差异均无统计学意义(P>0.05);鼻咽癌患者原发灶、颈部转移性小淋巴结、转移性大淋巴结ADC值均显著低于良性淋巴结肿大患者(P<0.05)。在b值分别取400、600、800、1000s/mm^2时,其对应的ROC曲线下面积分别为0.77、0.82、0.91、0.87。当b=800s/mm^2时,其鉴别和诊断淋巴结良恶性的价值最高,此时ADC值诊断鼻咽癌颈部转移性小淋巴结的阈值为0.945×10^-3mm^2/s,诊断敏感度为98.49%,特异度为79.63%,约登指数为0.78。结论3.0T MR多b值DWI检查可有效区分良恶性淋巴结的性质,并且在b值为800s/mm^2时,其鉴别和诊断不同淋巴结性质的能力最强,可用于临床鉴别和诊断鼻咽癌患者颈部淋巴结转移瘤。

Value of multi b-value DWI of 3.0T MR in differential diagnosis of benign and malignant cervical lymph nodes in patients with nasopharyngeal carcinoma

Objective To analyze the value of multi b-value diffusion-weighted imaging(DWI)of 3.0T magnetic resonance(MR)in differential diagnosis of benign and malignant lymph nodes in the neck of patients with nasopharyngeal carcinoma.Methods A retrospective study was conducted to collect the clinical data of 66 patients with nasopharyngeal carcinoma from April 2018 to July 2019,and 35 patients with benign lymphadenopathy as control.All patients underwent routine MR plain scan,contrast-enhanced and multi b-value DWI imaging to compare the difference of apparent diffusion coefficients(apparent diffusion coefficient,ADC)between nasopharyngeal carcinoma patients with primary focus,cervical metastatic small lymph nodes,metastatic large lymph nodes and benign lymphadenopathy under different b-value.The diagnostic threshold,area under receiver operating characteristic(ROC)curve,sensitivity and specificity were calculated by drawing ROC curve,and the value of ADC under different b values in differentiating benign and malignant lymph nodes in the neck of nasopharyngeal carcinoma was evaluated.ResultsWith the increase of B value,the ADC of primary lesions,cervical metastatic small lymph nodes,metastatic large lymph nodes and benign lymphadenopathy in patients with nasopharyngeal carcinoma showed a decreasing trend.There was no significant difference in the ADC between primary lesions,cervical metastatic small lymph nodes and metastatic large lymph nodes in patients with nasopharyngeal carcinoma(P>0.05).The ADC of primary focus,cervical metastatic small lymph nodes and metastatic large lymph nodes in cancer patients were significantly lower than those in benign lymphadenopathy patients(P<0.05).When the b values were 400,600,800 and 1000 s/mm^2,the corresponding ROC curves were 0.77,0.82,0.91 and 0.87,respectively.When b=800 s/mm^2,the value of differential diagnosis and diagnosis of lymph node benignity and malignancy was the highest.At this time,the threshold value of ADC for diagnosis of small metastatic lymph nodes in the neck of nasopharyngeal carcino-ma was 0.945×10^-3 mm^2/s,the diagnostic sensitivity was 98.49%,the specificity was 79.63%,and the Yoden index was 0.78.Conclusion Multi b-value DWI with 3.0T MR can effectively distinguish the nature of benign and malignant lymph nodes,and when the b value was 800 s/mm^2,it has the strongest ability to differentiate and diagnose the nature of different lymph nodes,so it can be used to differentiate and diagnose the cervical lymph node metastases of nasopharyngeal carcinoma patients.