核磁共振弥散加权成像对局部晚期食管癌放疗靶区勾画的作用

Effects of magnetic resonance diffusion weighted image on the target volume delineation of advanced esophageal cancer

目的研究DWI影像联合T2WI影像与CT影像融合技术的价值,探讨DWI影像对晚期食管癌放射治疗靶区范围确定的作用。方法 23例局部晚期食管癌单纯放疗病例,采用放疗所需体位及固定方法,同时对患者进行CT定位扫描、T2WI及DWI定位扫描。将获得的3个序列影像经网络传输至Eclipse治疗计划系统,使用治疗计划系统的归一化信息自动融合法对影像进行融合。由放疗医师分别在CT影像和CT与DWI融合影像上对靶区范围进行勾画。应用治疗计划系统的图像融合功能及统计功能对两种影像确定的靶区进行评价。结果以CT影像为参考确定的食管癌靶区体积及长度,相对于以CT和DWI融合图像为参考确定的食管癌靶区体积及长度之间具有明显差异;临床医师应用CT与DWI融合图像勾画的食管癌靶区体积及长度结果3个组之间更为接近。结论 DWI与CT融合图像能清楚地反映肿瘤靶区的范围,对局部晚期食管癌的靶区确定有良好的辅助作用。

Objective To investigate the value of DWI imaging combined with T2WI imaging and CT image fusion technology and explore the role of DWI imaging in the determination of target areas in radiotherapy for advanced esophageal cancer. Methods Twenty-three patients with locally advanced esophageal cancer were included in this study. All the patients were fixed by a heat plastic device. Each patient was examined by CT, T2WI and DWI scan in the same position as the radiotherapy treatment. Images obtained from the three sequences were transmitted to the Eclipse 11.0 treatment planning system. All images were registered at Eclipse workstation as to normalized mutual information registration. The target areas were delineated by the clinical radiation physicians in the CT imaging, and CT and DWI fusion images. The target areas of the two kinds of image were evaluated using fusion function and statistical function of the treatment planning system. Results Target parameters differed significantly between CT base and CT/MRI fusion base. The results of the target volume outline closer by CT and MRI fusion image base in the three groups of clinicians. Conclusion The target volume between the groups is closer by using CT and DWI fusion image. DWI image has a good assisting effect in determining the target area of locally advanced esophageal cancer.