MRI扩散加权成像在非小细胞肺癌靶向治疗早期疗效评价中的应用价值

目的评价磁共振扩散加权成像(MRI-diffusion weighted imaging，MRI-DWI)在非小细胞肺癌靶向治疗早期疗效评价中的应用价值。 方法选择32例病理证实非小细胞肺癌患者，于治疗前、1周期靶向治疗后行胸部常规MRI检查、DWI检查及CT增强检查，以第2周期靶向治疗后相对于治疗前的肿瘤最大径变化率为标准，将患者分为有效组（19例）和无效组（13例），比较两组治疗前后肿瘤表观扩散系数(ADC)值及最大径的差异。同时比较MRI-DWI与增强CT对肿瘤及阻塞性肺不张的显像效果。 结果肿瘤最大径在两组内不同时间及组间的差异均无统计学意义（P>0.05）。第1周期靶向治疗后，有效组肿瘤平均ADC值明显升高（×10^-3 mm²/s：1.48±0.23 vs. 1.23±0.21，t=-15.45，P<0.01），而无效组治疗后ADC值变化不大（×10^-3 mm²/s：1.20±0.27 vs.1.15±0.32，t=-1.69，P>0.05），并且有效组ADC值的升高率明显高于无效组（%：17.7±5.7 vs. 4.6±2.1，t=6.72，P<0.01）。CT图像可显示清楚肿瘤与不张肺组织边界6例（37.5%），MRI-DWI图像可显示肿瘤与肺不张组织边界13例（81.3%），高于CT图像，差异有统计学意义（χ²=6.35，P<0.05）。 结论MRI-DWI较增强CT可更清晰地显示肺不张与肺肿瘤边界，便于肿瘤大小测量及疗效评估，ADC值可以对非小细胞肺癌靶向治疗疗效做出早期监测。

Value of diffusion weighted MRI imaging in early response to target therapy of non-small-cell lung cancer

Objective:To assess the value of diffusion weighted imaging in early response to target therapy of non-small-cell lung cancer. Methods:32 patients with non-small-cell lung cancer were selected in this study. MRI imaging,DWI and contrast-enhanced CT were performed before and after the first cycle of target therapy. These patients were divided into responding and non-responding group according to the tumor maximum diameter shrinkage rate after the second cycle of target therapy. ADC value of the tumor and the tumor maximum diameter between two groups were compared. MRI combined with DWI and contrast-enhanced CT were also compared for the imaging effect of tumor and obstructive atelectasis. Results:There were no significantly statistical difference in tumor maximum diameter between pre-therapy and post-therapy in both groups(P>0.05). After the first cycle of target therapy,the mean ADC values increased significantly in responding group (×10^-3 mm²/s:1.48±0.23 vs. 1.23±0.21, t= -15.45, P<0.01) while it showed little change in non-responding group (×10^-3 mm²/s:1.20±0.27 vs. 1.15±0.32, t= -1.69, P>0.05). The increase rate of ADC value in responding group was considerably higher than that in non-responding group(%:17.7±5.7 vs. 4.6±2.1, t=6.72, P<0.01). There was also significantly statistical difference in imaging effect of tumor and obstructive atelectasis between MRI combined with DWI(13 cases 81.3%) and contrast-enhanced CT(6 cases, 37.5%)(P<0.05). Conclusions:Compared to contrast-enhanced CT, MRI combined with DWI present the boundary of lung tumor and atelectasis more clearly and provide a better tool for the measurement of tumor size and the assessment of therapy effect. ADC value can be a promising biomarker for detecting target therapy responses at an early stage in non-small-cell lung cancer.