4DCT全时相与PET-CT不同SUV阈值勾画胸段食管癌IGTV的比较研究

Comparison between IGTVs based on ten phases of 4DCT and nine PET-CT SUV thresholds in primary thoracic esophageal cancer

目的 比较基于4DCT 10个时相与基于PET-CT不同SUV值勾画的IGTV的大小和CI、DI值.方法 15例胸段食管癌患者序贯完成3DCT、4DCT、FDG PET-CT胸部定位扫描.在4DCT各时相图像上分别勾画IGTV并融合获得IGTV10.基于不同SUV值（≥2.0、2.5、3.0、3.5）及SUVmax的不同百分比（≥20％、25％、30％、35％、40％）分别在PET图像上勾画IGTVPET2.0、IGTV PEr2.5、IGTV PET3.0、IGTVPET3.5、IGTVPET20％、IGTVPETr25％、IGTVPET30％、IGTVPET5％、IGTVPET40％.两两比较采用配对t检验,靶区中心间距与CI、DI值相关性采用Pearson法分析.结果 IGTVPET2.5、IGTVPET20％与IGTV10体积相近（体积比0.92、1.08,P=0.985、0.886）,IGTVPET2.0、IGTV PET2.5、IGTVPET20％与IGTV10间CI值也相近（0.53、0.52、0.53,P=0.432,1.00,0.414）,但三者均明显大于其他6个IGTVPET与IGTV10间的CI值（0.33 ～0.50,P=0.000 ～0.047）.IGTVPET2.5对IGTV10的DI （0.74）与IGTVPET-20％对IGTV 10的DI（0.72）也相近（P =0.542）,IGTV10对IGTVPET2.5的DI （0.67）与IGTV10对IGTV PET20％的DI也相近（P=0.539）.结论 SUV阈值为2.5及最大值的20％时,基于PET-CT勾画的IGTVPET与基于4DCT 10个时相构建的IGTV10体积大小接近且空间错位程度相对较小.

Objective To compare the volume,conformity index （CI）,and degree of inclusion （DI） between internal gross tumor volumes （IGTVs） delineated based on ten phases of four-dimensional computed tomography （4DCT） and nine positron emission tomography （PET）-CT standardized uptake value （SUV） thresholds.Methods Fifteen patients with thoracic esophageal cancer sequentially underwent 3DCT,4DCT,and FDG PET-CT of the thorax simulation.IGTVs were delineated on ten phases of 4DCT images and then combined to obtain IGTV10.IGTVPET2.0,IGTVPET2.5,IGTVPET3.0,IGTVPET3.5,IGTVPET20%,IGTVPET25%,IGTVPET30%,IGTVPET35%,and IGTVPET40% were delineated on PET images based on different SUV thresholds （≥2.0,2.5,3.0,and 3.5） and percentages of SUVmax （≥20%,25%,30%,35%,and 40%）.The volume,CI,and DI were compared between IGTVs by paired t test.The correlations of centroid distance with CI and DI were determined by Pearson correlation analysis.Results The volumes of IGTVPET2.5 and IGTVPET20% were similar to that of IGTV10,with volume ratios of 0.92（P =0.985） and 1.08 （P =0.886）,respectively.The CIs of IGTVPET2.0 vs IGTV10,IGTVPET2.5 vs IGTV10,and IGTVPET20% vs IGTV10 were similar （0.53,0.52,and 0.53 ; P =0.432,1.00,and 0.414）,but they were significantly higher than the CIs of other IGTVPET vs IGTV10 （0.33-0.50,P =0.000-0.047）.No significant differences existed between the DIs of IGTV10 in IGTVPET2.5 （0.67） and IGTV10 in IGTVPET20% （0.70）（P =0.542） and between the DIs of IGTVPET2.5 in IGTV10 （0.74） and IGTVPET20% in IGTV10 （0.72） （P=0.539）.Conclusions IGTVPET2.5 and IGTVPET20% have similar volumes and good spatial matching compared with IGTV10.