MR扩散加权成像预测鼻咽癌放疗预后的价值

Discussion of the diffusion weighted imaging on predicting therapeutic effect of radiotherapy treatment in nasopharyngeal carcinoma

目的：探讨MR DWI及ADC在鼻咽癌放疗后随访中的应用价值。方法回顾性对比分析鼻咽癌放疗后局部复发（24例）和非复发患者（38例）的临床资料。观察这些患者放疗前、放疗结束后3、6、12个月的常规MRI及DWI影像表现，测量病灶区的ADC值。采用SPSS 18.0统计学软件对检测数据进行统计分析，运用ROC分别对放疗后3、6、12个月随访所得的ADC值进行效能分析，计算其预测鼻咽癌复发的诊断阈值。结果鼻咽癌原发灶和复发灶的DWI图呈高信号，放疗后非复发患者病灶区的DWI图呈低信号或混杂信号；复发组与非复发组原发灶的ADC值分别为（0.709±0.078）×10-3和（0.693±0.089）×10-3mm2/s，两者差异没有统计学意义（t=-0.717,P〉0.05）；复发组中复发灶与原发灶的ADC值分别为（0.730±0.068）×10-3和（0.709±0.078）×10-3mm2/s，两者差异没有统计学意义（t=-1.000，P〉0.05）；复发组与非复发组放疗结束后3、6、12个月的ADC值分别为（1.128±0.179）×10-3、（1.358±0.145）×10-3mm2/s（t=5.567,P〈0.01），（1.164±0.174）×10-3、（1.450±0.102）×10-3mm2/s（t=7.310,P〈0.01），（1.107±0.180）×10-3、（1.584±0.125）×10-3mm2/s（t=11.189,P〈0.01），差异均有统计学意义。分别取ADC值1.29×10-3、1.32×10-3、1.37×10-3mm2/s作为放疗结束后3、6、12个月的诊断阈值预测肿瘤复发，其敏感度、特异度和准确性分别为83.3%、73.7%、77.4%，83.3%、89.5%、87.1%，100.0%、94.7%、96.3%。结论 DWI可应用于鼻咽癌放疗后的定期随访，测量鼻咽癌病灶放疗后ADC值有可能对局部复发进行预测。

Objective To discuss the application value of DWI and ADC on predicting therapeutic effect of radiotherapy treatment in NPC. Methods Twenty four local recurrent cases and 38 non-recurrent cases after radiotherapy treatment in NPC were reviewed. MRI and DWI-MRI were performed at pre-radiotherapy and 3, 6, 12 months after treatment, the ADC values of the lesions were analyzed by SPSS 18.0 statistical software. ROC curves based on the ADC values were measured in 3, 6, 12 months after treatment plotted to analyze the threshold ADC value for confirming recurrence. Results The recurrent group and newly diagnosed group showed significantly high signal on DWI, while the non-recurrent group acquired low or mixed signal. The ADC values of the primary tumor in the recurrent group and the non-recurrent group were （0.709 ± 0.078） × 10-3 and （0.693 ± 0.089） × 10-3mm2/s, respectively, t=-0.717,P〉0.05, respectively.The ADC values of the primary and recurrent tumor in the recurrent group were （0.730± 0.068） × 10-3mm2/s and （0.709 ± 0.078） × 10-3mm2/s, t=-1.000,P〉0.05 , respectively.There were statistical differences between the recurrent group and the non-recurrent group for ADC in 3, 6, 12 months aftertreatment：（1.128 ± 0.179） × 10-3 and （1.358 ± 0.145） × 10-3mm2/s, t=5.567,P〈0.01;（1.164 ± 0.174） and （1.450 ± 0.102） × 10-3mm2/s, t=7.310,P〈0.01;（1.107 ± 0.180） × 10-3 and （1.584 ± 0.125） × 10-3mm2/s, t=11.189,P〈0.01;respectively. Take 1.29 × 10-3 mm2/s,1.32 × 10-3mm2/s,1.37 × 10-3mm2/s respectively in 3, 6, 12months after treatment as the diagnostic threshold to predict tumor recurrence. The sensitive , specificity, and accuracy were （83.3%, 73.7%, 77.4%）, （83.3%, 89.5%, 87.1%）, （100.0%, 94.7%, 96.3%）.Conclusions Both DWI and ADC value are important for diagnosing and predicting recurrent NPC after radiotherapy treatment, DWI and ADC can be used to regular follow-up after radiotherapy, to further improve the rate of early diagnosis of recurrent NPC.