VX2兔脑瘤模型三维放疗解剖学靶区灌注CT与增强CT对照研究

A comparison of perfnsion computed tomography and contrast enhanced computed tomography on radiation target volume delineation using rabbit VX2 brain tumor model

目的 利用灌注CT血容量图（BV）评价兔VX2脑瘤模型大体靶体积（GTV）、临床靶体积（CTV）,并设增强CT（CECT）作为对照.方法 对20只成功建模兔VX2脑瘤模型行灌注CT检查,测量脑瘤兴趣层面在增强CT、血容量（BV）图像上长、短径,并与其同层病理学GTV、CTV结果比较.结果 20例GTVBV长、短径平均值分别为（11.98±3.29）、（7.03±1.82）mm,GTVCECT的分别为（6.36±3.85）、（3.17±1.93）mm,同层病理学GTV的分别为（8.19±2.29）、（4.83±1.31）mm,CTV的分别为（12.87±3.74）、（7.71±2.15）mm.GTVBv与GTV病理长、短径均不同（t=7.17,P=0.000和t=8.37,P=0.000）.GTVCECT与GTV病理、CTV病理长、短径也均不同（t=-3.18,P=0.005和t=-4.24,P=0.000;t=-11.59,P=0.000和t=-9.39,P=0.000）.GTVBv与CTV病理长、短径相似（t=-1.95,P=0.067和t=-2.06,P=0.054）.采用CECT评价CTV病理的长、短径外放比例平均值分别为81.83%±40.33%、276.73%±131.46%,利用GTVBV评价脑瘤CTV的长、短径外放比例平均值分别为7.93%±17.84%、12.52%±27.83%（t=-7.36,P=0.000和t=-8.78,P=0.000）.结论 灌注CT的BV图较传统CECT能更好评价脑瘤的解剖学靶区.

Objective To compare the accuracy of blood volume perfusion imaging （perfusion CT）with contrast enhanced 64-slice spiral computed tomography （CECT） in the evaluation of gross tumor volume （GTV） and clinical target volume （CTV） using rabbits with VX2 brain tumor. Methods Perfusion CT and CECT were performed in 20 rabbits with VX2 brain tumor. The GTV and CTV calculated with the maximal and minimal diameter of each tumor in the blood volume （BV） maps and CECT were measured and compared to those in pathological specimens. Results The mean value of the maximal and minimal diameter of GTV was （8.19 ± 2. 29） mm and （4.83 ± 1.31） mm in pathological specimens, （11.98 ±3.29） mmand （7.03±1.82） mm in BV maps, while （6.36±3.85） mm and （3.17±1.93） mm in CECT images, which were significantly different （pathological specimen vs. BV map, t = 7. 17,P =0. 000;pathological specimen vs. CECT, t = 8.37, P = 0. 000, respectively）. The mean value of the maximal and minimal diameter of CTV in pathologic specimens was （12.87 ± 3.74） mm and （7.71 ± 2. 15） mm, which was significantly different from that of GTV and CTV in CECT （t = - 3. 18, P = 0. 005 and t = - 4. 24, P =0. 000;t= -11.59,P=0.000 and t= -9.39,P=0.000）, while similar with that of GTV in BV maps （t = - 1.95,P = 0. 067; t = - 2. 06, P = 0. 054）. For CECT, the margin from GTV to CTV was 81.83% ±40.33% for the maximal diameter and 276.73% ± 131.46% for the minimal. While for BV maps, the margin was 7.93% ± 17. 84% and 12.52% ± 27. 83%, which was significant different from that for CECT images （t=7.36,P=0. 000 and t= -8.78,P=0.000）. Conclusions Compared with CECT, the BV map from 64-slice spiral CT peffusion imaging might have higher accuracy in target volume delineation for brain tumor.