磁共振多b值弥散加权成像评价直肠癌淋巴结转移的价值

目的探究磁共振多b值弥散加权成像(diffusion weighted imaging,DWI)在直肠癌淋巴结诊断方面的临床意义。材料与方法回顾性分析吉林大学中日联谊医院80例经肠镜及术后病理证实为直肠癌患者的DWI图像;DWI多b值扫描,b=0、20、30、50、600、800、1000 s/mm~2;通过工作站分析软件后处理,基于多b值生成表观弥散系数(apparent diffusion coefficient,ADC)图。将淋巴结病理结果作为金标准,将患者分为A、B两组(转移/非转移淋巴结组),回顾性分析不同b值下淋巴结检出率;测量大小不同淋巴结,多b值ADC图的淋巴结检出率;测量A、B两组淋巴结多b值ADC值,测量转移淋巴结鉴别诊断敏感性、特异性。结果(1)随b值增加(0~1000 s/mm~2),淋巴结检出率递减;DWI图像淋巴结信噪比递增。(2)直径8 mm以上淋巴结,多b值DWI图像检出率一致,无明显统计学差异。(3)高场强多b值弥散加权成像,A组与B组淋巴结ADC有统计学差异。(4)当ADC值为0.98×10~(-3)mm~2/s时,诊断转移淋巴结敏感度为63.7%、特异度为93.2%。结论高场强多b值弥散加权成像鉴别直肠癌淋巴结性质,具有中等敏感性、高度特异性。

Rectal cancer lymph node can be identified by diffusion-weighted MRI with multiple b values

Objective: To prospectively assess the diagnostic performance of diffusion-weighted (DWI) magnetic resonance imaging(MRI) in the detection of rectal cancer metastasis lymph nodes by using multiple b values and T2 weighted Imaging. Materials and Methods: Review of 80 cases of endoscopic and postoperative pathology confirmed DWI images of rectal cancer patients of China-Japan Friendship Hospital Affiliated Jilin University; DWI multi b scan, b values was 0, 20, 30, 50, 600, 800, 1000 s/mm2; Through analysis of workstation software, based on b value generated table apparent diffusion coefficient apparent diffusion coefficient (ADC) diagram. According to pathological results, will be divided into group A/B(metastasis lymph nodes and the metastasis lymph node), retrospective measurement and analysis of different b values metastasis lymph node detection rate; Measuring the size of different lymph nodes, multiple b value of ADC figure that lymph node detection rate;Analysis of more than two sets of lymph node b value of ADC value, the measurement of lymph node metastasis of sensitivity, specificity, ROC curve drawing. Results:(1)With the increase of b value (0—1000 s/mm2), lymph node detection rate decline;Ratio that image lymph nodes signal-to-noise of DWI can increasing. (2)More than 8 mm diameter lymph nodes, b value of DWI image detection rate is consistent, be more no significant statistical difference. (3)The high field strength more b value, the difference of group A/B lymph node with ADC values was statistically significant. (4)The best cut-off point for diagnosis the nature of lymph node, ADC values is 0.98×10–3mm2/s has a moderate sensitivity, high specificity. Conclusion: Identification the nature of lymph node, high field strength b value of DWI imaging can be more effective with high specificity and medium sensitivity.