磁共振弥散加权成像在食管癌大体肿瘤靶区勾画中的应用价值

目的 探讨磁共振弥散加权成像(DWMRI)在食管癌大体肿瘤体积(GTV)勾画中的应用价值。方法 29例行根治性食管癌切除术的食管鳞癌患者术前行常规CT、T₂WI下MRI及DWMRI (弥散敏感梯度b=400、600、800 s/mm²),分别在上述3种图像上勾画GTV。测量3种方法GTV长度并与术后标本上测量的病变长度比较,以确定最佳方法和条件,并计算该条件下外扩范围满足GTV照射要求的患者比例。利用放疗计划系统的图像融合功能将不同b值下DWMRI图像与CT图像融合,验证融合图像上勾画GTV的可行性。结果 CT和T₂WI下MRI图像上测量的GTV长度和标本上测量的病变长度差值分别为3.368 mm和2.84 mm;b=400、600、800 s/mm²时DWMRI图像上测量的GTV长度和标本上测量的病变长度差值分别为0.47、－0.47、－1.53 mm,其相关系数分别为0.928、0.927、0.938。DWMRI与CT图像在放疗计划系统中能很好融合,融合图像上食管癌病变两端分界清晰。结论 DWMRI能比较准确显示食管癌GTV长度和位置,利用放疗计划系统的图像融合功能可将DWMRI与CT图像进行融合并用于食管癌GTV勾画。

The application value of diffusion-weighted magnetic resonance imaging in gross tumor volume delineation of esophageal squamous cell carcinoma

Objective To analyze the application value of diffusion-weighted magnetic resonance imaging (DWMRI) in gross tumor volume (GTV) delineation of esophageal squamous cell carcinoma (SCC). Methods Twenty-nine patients with esophageal SCC treated with radical surgery were analyzed. Routine CT scan, MRI T₂-weighted and DWMRI were employed before surgery;diffusion-sensitive gradient b-values were taken 400, 600 and 800 s/mm². GTVs were delineated using CT, MRI T₂-weighted images and DWMRI under different b-value images. The length of GTVs measured under different images was compared with the pathological length and confirm the most accurate imaging condition. Use radiotherapy planning system to fuse DWMRI images and CT images to investigate the possibility of delineate GTVs on fused images. Results The difference of GTV length value between CT, T₂WI images and specimen was 3.36 mm and 2.84 mm. When b=400, 600 and 800 s/mm², the difference between GTV length value on the DWMRI images and on specimen was 0.47 mm, －0.47 mm and －1.53 mm;the correlation coefficient of the measuring esophageal lengths on DWMRI images and the pathological lengths was 0.928, 0.927 and 0.938. DWMRI images and CT images could fuse accurately on radiotherapy planning system. GTV margin could.show clearly on fused images. Conclusions DWMRI images can display the esophageal carcinoma lengths and margin accurately. When DWMRI images fused with CT images, GTV margin could show clearly, it can be used to delineate GTV accurately.