肺内孤立灶大体肿瘤体积CT不同扫描方式比较

目的 比较CT不同扫描方式对肺内孤立病灶大体肿瘤体积(GTV)勾画影响,探讨螺旋扫描在CT模拟定位中的可行性。方法 对 16例周围型或转移性肺癌分别行轴位(A)、螺旋(S) CT扫描,比较GTV_A、GTV_s大小和位置差异(配对t检验),计算GTV_A、GTV_s匹配指数(MI)及与体积相关性(两变量相关分析)。结果 GTV_A、GTV_s大小分别为8.95、9.38 cm³(t=0.43,P=0.667)。GTV_A、GTV_s等中心点坐标值x轴分别为6.80、6.81 cm (t=0.27,P=0.794),y轴分别为36.19、36.05 cm (t=0.37,P=0.717),z轴分别为4.99、4.96 cm (t=0.65,P=0.526)。GTV_A和GTV_s等中心点至坐标原点距离相似(38.31 cm∶38.23 cm,t=0.47,P=0.646)。GTV_A与GTV_s的MI为0.36(0~0.77),MI与体积显著相关(r=0.587,P=0.017)。结论 轴位与螺旋CT扫描方式确定肺内孤立灶GTV的MI与其有相关性,螺旋扫描速度更快,在肺内孤立灶CT模拟定位中具有可行性。

A comparison of the different CT scanning modes on the GTV delineation of the solitary pulmonary lesion

Objective To explore the influence of the CT scanning mode on the gross tumor volume (GTV) delineation of solitary pulmonary lesion (SPL), and to evaluate the feasibility of the spiral CT scan in CT simulation. Methods Sixteen patients with SPL underwent axial scan, spiral scan during free breathing. Compare the target position, volume between GTV_s and GTV_A (paired t-test). The matching index (MI) between GTV_s and GTV_A and correlations between MI and the tumor volume were calculated (bivariate correlation analysis). Results GTV_s and GTV_A volume was 8.95 cm³ and 9.38 cm³(t=0.43,P=0.667), respectively. The centroid position for GTV_s and GTV_A in x,y and z axises were 6.80 cm and 6.81 cm (t=0.27,P=0.794), 36.19 cm and 36.05 cm (t=0.37,P=0.717), and 4.99 cm and 4.96 cm (t=0.65,P=0.526),respectively. There were also no statistically significant difference in the distance between the centroidal position and origin of coordinates for GTV_s and GTV_A (38.31 cm∶38.23 cm,t=0.47,P=0.646). MI between GTV_s and GTV_A was 0.36(range 0－0.77), correlated with the tumor volume (r=0.587, P=0.017). Conclusions There was no significant difference between the axial scan and spiral scan in the GTV volume and position for SPL, but MI between GTV_s and GTV_A were small. A correlation was found for the MI between GTV_s and GTV_A with the tumor volume. Spiral CT scan was more timesaving, and was feasible in CT simulation scan.