基于主动呼吸控制辅助3DCT与4DCT扫描确定周围型肺癌内大体肿瘤体积比对研究

Comparison of internal gross tumor volume for peripheral lung cancer based on four dimensionalCT or three dimensional CT assisted with active breathing control

目的 比较基于主动呼吸控制（ABC）辅助三维CT（3DCT）扫描与基于自由呼吸3DCT及四维CT（4DCT）扫描所构建周围型肺癌内大体肿瘤体积（IGTV）中心点位置、体积大小及匹配指数（MI）的差异.方法 18例周围型肺癌患者,序贯完成自由呼吸胸部3DCT和4DCT扫描及ABC辅助平静吸气末和平静呼气末3DCT扫描.4DCT 10个时相GTV融合得到IGTV10,0％和50％时相的GTV融合得到IGTV2,基于最大密度投影（MIP）图像构建IGTVMIP,自由呼吸3DCT图像GTV外扩基于4DCT测得的运动范围得到IGTV3D,平静吸气末和呼气末屏气3DCT图像GTV融合得到IGTVABC.结果 上叶组IGTVABC与IGTV10中心位置在左右方向上差异有统计学意义（t=-2.377,P ＜0.05）,与IGTVMIP中心位置在前后方向上差异有统计学意义（t=-2.199,P＜0.05）,与IGTV2、IGTV3D中心位置在左右和前后方向上差异有统计学意义（t=-2.185 ～2.767,P＜0.05）；下叶组IGTVABC与IGTV10、IGTVMIP、IGTV3D中心位置在左右方向上差异有统计学意义（t=3.950～4.543,P ＜0.05）.上叶组及下叶组IGTV10、IGTV3D与IGTVABC的体积比较,差异有统计学意义（Z=-3.180～-2.023,P＜0.05）,IGTVABC与其他IGTV的匹配指数上叶组大于下叶组,差异有统计学意义（Z=-2.419～-2.119,P＜0.05）.结论 IGTVABC与基于4DCT扫描图像所构建的各种IGTV和基于自由呼吸3DCT扫描图像所构建的IGTV均不完全重合,这种空间错位与肿瘤部位相关,肺中下叶肿瘤较肺上叶肿瘤显著.IGTVABC体积大于IGTV2,但小于基于4DCT图像所构建的其他各种IGTV及基于自由呼吸3DCT图像所构建的IGTV.

Objective To compare the differences of the position, volume and matching index （MI） between internal gross tumor volumes （IGTVs） determined by four methods based on four dimensional CT （4DCT） and three dimensional CT （3DCT） scans during free breathing and IGTV determined by one method based on 3DCT assisted with active breathing control. Methods Eighteen patients with peripheral lung cancer underwent 3DCT and 4DCT simulation scans during free breathing and then underwent 3DCT simulation scans in end inspiration hold （CTFas ） and end expiration hold （CTEEs ）. IGTVs were acquired using five methods： the gross tumor volme （GTV） contours from ten respiratory phases were combined into IGTV10; The GTV contours from 0% and 50% phases were combined into IGTV2 ; IGTVmp was the GTV contour delineated from the maximum intensity projection （ MIP ） ; IGTV3D was acquired from the enlargement of 3DCT-based GTV by each spatial direction on the motion amplitude measured in 4DCT; IGTVA^c was acquired by combining GTVs from CTrm and CTEEH. Results In upper lobe group, there were significant differences in eentroid position between IGTVAsc and IGTV10 in lateral （LR） , and IGTVMIp in anterio-posterior （AP） directions respectively （ t = - 2. 377, - 2. 199, P 〈 0. 05 ） , and there were significant differences in centroid position between IGTVAsc and IGTV2, IGTV3D in both LRand AP directions （t = - 2. 185 - - 2.767, P 〈 0.05）. In lower lobe group, there were significant differences in centroid position between IGTVAsc and IGTVI0, IGTVMIe, IGTV3D in LR direction （t = 3. 950 -4. 543, P 〈0. 05）. ,Either in the upper lobe group or in the lower lobe group, IGTVABc was smaller than IGTVI0 or IGTV3o significantly （ Z = - 3. 180 - - 2. 023, P 〈 0.05 ） , and the MIs between IGTVABc and other IGTVs were larger in the upper lobe group thanin the lower lobe group significantly （Z = -2. 419-2. 119, P 〈 0. 05）. Conclusions IGTVABc is not completely coincide with IGTVs acquired based on 4DCT or 3DCT during free breathing, and the spatial mismatch correlated with the tumor position, the spatial mismatch is more significant for middle-lower lobe tumor than upper lobe tumor. IGTVABc are larger than IGTVz but smaller than other IGTVs acquired based on 4DCT and IGTV acquired based on 3DCT during free breathing.