应用CT-MRI图像融合技术准确设定脑胶质瘤肿瘤靶区体积的研究

 目的　探讨调强放射治疗（IMRT）时应用CT-MRI图像融合技术准确设定高分级胶质瘤（HGG）肿瘤靶区体积（GTV）的方法。方法　19例HGG患者均采集CT、MRI图像，将两种影像融合。每位患者均由一位主任医师和一位住院医师分别独立依据增强CT、MRIT1增强序列勾画GTV，并叠加得到融合的GTV。计算各个GTV：GTVCT、GTVMRI 、GTVCT+MRI，详细比较各GTV之间的差异。结果　经主任医师和住院医师勾画，均GTVMRI ＞GTVCT（均P＜0.050）。GTVMRI／GTVCT+MRI：主任医师勾画为（98.57±7.00）%，住院医师勾画为（97.84±10.00）%。术后放疗患者与单纯放疗者GTVCT与GTVMRI间差异有统计学意义（P＝0.046）。依据CT图像，主任医师勾画的GTV大于住院医师所勾画（P＝0.020）；依据MRI或融合图像，两级医师勾画的GTV间差异无统计学意义（均P＞0.050）。结论　对于HGG患者，GTV的准确设定必须综合CT与MRI的影像信息，包括应用CT-MRI融合技术，术后放疗的HGG患者更应如此。融合GTV应为依据增强CT及MRIT1增强序列勾画的GTV的叠加，并且，GTV必须由经验丰富的医师勾画或审核。

Evaluation CT with MRI image fusion technique on delineation GTV for glioma

Objective To investigate the way to accurately delineate gross tumor volume (GTV) of high grade gliomas(HGG) for intensity modulated radiation therapy (IMRT) by using computed tomography (CT) and magnetic resonance imaging (MRI) image fusion technique. Methods CT and MRI images were fused from 19 patients. The GTV of each patient were independently delineated by one chief doctor and one resident doctor on CT and MRI image. The GTV contoured on CT (GTVCT), MRI (GTVMRI) were measured, and composite volumes (GTVCT+MRI) were the sum of CT-defined GTV and MRI-defined GTV. The differences of these volumes were compared. Results Whether chief or resident doctors delineated, all were GTVMRI ＞GTVCT(P ＜0.050). The percentages of GTVMRI on GTVCT+MRI were (98.57±7.00)% by chief doctors, and (97.84±10.00)% by resident doctors. Compared the difference between GTVCT and GTVMRI in postoperative patients and preoperative patients, P =0.046, and the difference between chief doctors and resident doctors was statistically significant for GTV defined by CT (P =0.020), but not by MRI and composite image (P ＞0.050).Conclusion The GTV of HGG patients must be delineated on both CT image and MRI image, including using CT and MRI image fusion. But the composite volumes(GTVCT+MRI) should be the sum of CT-defined GTV and MRI-defined GTV. Especially for the postoperative patients,delineating GTV should be taken more attention. And the GTV should be delineated by doctors with full experiences.