多层螺旋CT灌注成像在肺癌放射治疗中的研究

Application of CT perfusion imaging in radiotherapy for lung cancer

目的通过多层螺旋CT灌注成像对肺癌放疗前和放疗中血流灌注特点的研究，探讨CT灌注成像技术在肺癌放疗中的实用性。方法对符合入组条件放疗的51例肺癌患者行CT灌注扫描，其中，22例于放疗前、放疗中，29例于放疗前进行CT灌注扫描。在静脉团注对比剂后采用电影扫描方式，快速动态扫描，选定CT平扫所示肿瘤最大层面灌注。在CT灌注原始图的相应部位画出感兴趣区，记录血容量（BV）、血流量（BF）、平均通过时间（MTT）、表面通透性（PS），并于治疗结束后2～4周复查CT，评价近期疗效。结果51例患者放疗前平均血容量为13．6ml／100g，血流量129．5ml·min^-1·100g^-1，MTT9．1s，Ps10．0ml·min^-1·100g^-1。22例患者放疗前和放疗中灌注CT的血容量分别为11．2和7．6ml／100g（t=1．28，P〉0．05），血流量分别为108．7和97．8ml·min^-1·100g^-1（t=0．40，P〉0．05），MTT分别为7．2和8．9s（t=-1．15，P〉0．05），Ps分别为6．8和7．8ml·min^-1·100g^-1（t=-0．57，P〉0．05），肿瘤面积分别为1920．3和1189．6mm。（t=3．98，P〈0．05）。小细胞肺癌和非小细胞肺癌患者放疗前MTT分别为12．9和6．5S（t=2．54，P〈0．05）。肿瘤面积≤10cm^2与〉10cm^2患者的MTT分别为11．2和5．8s（T=2．59，P〈0．05）。近期疗效缓解与未缓解患者的血容量分别为19．2和4．6ml／100g（t=3．62，P〈0．05）。疾病无进展生存期≤10个月与〉10个月患者的灌注参数差异无统计学意义。结论CT灌注对于肺癌的诊断及治疗具有一定的帮助，应进一步深入研究。

Objective To investigate the value of CT perfusion imaging in evaluation of therapeutic effect and prognosis in radiotherapy for lung cancer. Methods Fifty-one cases of lung cancer who were unable or refused to be operated on, 36 males and 15 females, aged 37 -80, underwent CT perfusion imaging,29 of which only before radiotherapy and 22 before and after radiotherapy twice. The images were collected by eine dynamic scanning （5 mm/4 slices） and input into the GE AW4.0 workstation for data processing. The slice positions of CT imaging were determined according to the largest tumor size in CT scan. Regions of interest of tumor were drawn at the region corresponding to the original images of CT perfusion. Radiotherapy was performed after CT perfusion imaging. Relevant parameters, including blood flow （BF）, blood volume （BV）, mean transit time （MTT）, and permeability surface （PS） were calculated. The treatment response after radiotherapy was evaluated by RECIST. At 2 -4 weeks after the treatment, CT examination was conducted once more. Results The tests of the 51 patients showed that the BV was 13.6 ml·100 g^-1, the BF was 129.5 ml·min^-1 ·100 g^-1,the MTT was 9. 1 s, and the PS was 10.0 ml· min -1.100 g ^-1 before radiotherapy. The tests of the 22 of the 51 patients showed that the values of BV and BF after radiotherapy were 7.6 ml· 100 g^-1 and 97.8 ml·min^-1· 100 g^-1, respectively, both lower than those before radiotherapy （ 11.2 and 108.7 ml·min^-1·100 g^-1, respectively） , however, both not significantly （t = 1.28,0. 40, P 〉 0.05） ; and the values of MTT and PS after radiotherapy were 8.9 s and 7.8 ml·min^-1· 100 g ^-1 , respectively, both not significantly higher than those before radiotherapy （7.2 s and 6.8 ml-min-l·100 g-l, respectively, t = - 1. 15, -0.57, P〉 0. 05）. The mean area of tumor after radiotherapy was 1189.6 mm^2, significantly less than that before radiotherapy （ 1920.3 mm^2 , t = 3.98, P 〈 0.05 ）. The MTT of the SCLC patients was 12.9 s, significantly longer than that of the NSCLC patients （6.5 s, t = 2.54, P 〈 0. 05）. The MTT of the tumor with the area ≤ 10 cm^2 was 11.2 s, significantly longer than that of the tumors with an area 〉 10 cm2 （5.8 s,t = 2. 59, P 〈 0. 05）. The BV of the responder group was 19.2 ml. 100 g - 1, significantly higher than that of the non- responder group （4.6 ml.100 g-1 , t =3.62, P 〈0.05）. There were not significant differences in all the perfusion characteristics between the cases with the disease-free advanced survival time ≤ 10 months and those with disease-free advanced survival time 〉 10 months. Conclusions CT perfusion imaging helps in diagnosis and radiotherapy of lung cancer to a certain degree.