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目的探讨食管癌磁共振扩散加权成像(DWI)诊断的最佳b值及表观扩散系数(ADC)在食管癌恶性度预测方面的应用价值。方法对初诊为食管癌的45例患者行前瞻性常规MRI平扫及DWI扫描,依据病理结果对照分析不同病理分级食管癌间的ADC值变化。采用单次激发SE-EPI序列,取不同b值(500、800 s/mm~2和1000 s/mm~2)对食管癌患者进行DWI检查,得到相应的DWI及ADC图像。结果食管癌病灶在各组不同b值获得的DWI图像上均表现为高信号,同时病灶的信噪比(SNR)及对比噪声比(CNR)均随着b值的升高而表现为下降;各b值下病灶的ADC值不同,同一b值下不同病理分级间病灶的ADC值亦不相同,食管癌的病理分级可以通过各b值下的ADC值进行有效的评价。绘制ROC曲线后分析得出,当b值为500 s/mm~2时,受试者工作特征曲线(ROC)曲线下面积最大,对食管癌恶性度的预测价值最高,相应的ADC值为1.72×10~(-3)mm~2/s,其敏感度和特异度为85.7%和82.4%。结论 b值为500 s/mm~2时有利于食管癌病灶的检出和显示;ADC值测定可以反映肿瘤的病理分级,对于术前评估食管癌的恶性程度有重要作用,可以为临床治疗及患者预后评价提供更多的信息。
Objective To investigate the value of optimal b value and apparent diffusion coefficient (ADC) in the prediction of malignant degree of esophageal carcinoma in esophageal cancer with diffusion weighted imaging (DWI). Methods Forty-five patients with newly diagnosed esophageal cancer underwent routine MRI and DWI scanning. The ADC value of esophageal cancer with different pathological grades was analyzed according to the pathological results. Using single-shot SE-EPI sequence, DWI was performed on patients with esophageal cancer with different b values (500,800 s / mm ~ 2 and 1000 s / mm ~ 2), and corresponding DWI and ADC images were obtained. Results The lesions of esophageal cancer showed high signal intensity on DWI images of different b values, and the SNR and CNR of lesions decreased with the increase of b value. The ADC values of lesions under different b values were different, and the ADC values of lesions under different b values were also different. The pathological grade of esophageal carcinoma could be effectively evaluated by the ADC value under each b value. After the ROC curve was drawn, the area under the receiver operating characteristic curve (ROC) curve was the highest when the b value was 500 s / mm ~ 2, which had the highest predictive value for the malignancy of esophageal cancer with a corresponding ADC value of 1.72 × 10 ~ (-3) mm ~ 2 / s, the sensitivity and specificity of 85.7% and 82.4%. Conclusion The b value of 500 s / mm ~ 2 is beneficial to the detection and display of esophageal cancer lesions. The determination of ADC value can reflect the pathological grade of the tumor and plays an important role in the evaluation of the malignant degree of esophageal cancer before surgery. It can be used for clinical treatment and Patient prognosis evaluation provides more information.