兔VX2肺肿瘤低剂量CT灌注成像的可行性研究

目的前瞻性评估兔VX2肺种植肿瘤低剂量和常规剂量CT灌注检查测量参数的可重复性。方法 10只肺种植肿瘤新西兰大白兔间隔24 h行两次CT灌注检查（常规剂量120 kV,100 mAs;低剂量120 kV,50 mAs）,分别测量肿瘤体积、最大径、血容量（BV）、血流量（BF）、达峰时间（TTP）、表面通透性（PS）、Patlak血容量（PBV）、Pat-lak R方程（PatRsq）及Patlak残差（PatRes）。使用配对t检验和Bland-Altman法分析2组CT测量数据的一致性和可重复性。结果两次CT检查所有的CT灌注参数均显示较好的一致性。配对t检验显示常规剂量和低剂量CT灌注参数差异无统计学意义（P〉0.05）。组内相关系数（ICC）均大于0.49（P〈0.05）,个体间变异系数（WCV）为10.68%～29.52%。Bland-Altman图显示所有的CT灌注参数均有较好的重复性。结论兔肺VX2种植肿瘤低剂量CT灌注成像是可行的。

Feasibility of Quantitative Parameter Measurements at Reduced X-ray Dose CT Perfusion in Rabbits with Implanted VX2 Lung Tumours

Objective To prospectively assess the reproducibility of CT perfusion parameters acquired with normal dose and low dose in rabbits with implanted VX2 lung tumours.Methods Two times of perfusion CT were performed with 24-hour interval in 10 New Zealand white rabbits with implanted VX2 lung tumours by means of using routine（120 kV,100 mAs） and low（120 kV,50 mAs） dose.The volume,maximum diameter,blood volume（BV）,blood flow（BF）,time to peak（TTP）,permeability surface（PS）,patlak BV（PBV）,Patlak R square（PatRsq） and Patlak residual（PatRes） were respectively measured,and the agreement and reproducibility for these parameters between the routine dose and low dose was determined by using the paired t test and Bland-Altman analysis.Results CT perfusion parameters showed good agreement between the two perfusion examinations.The paired t test analysis showed that there was no statistically significant difference between the routine dose and the low dose data.Intragroup correlation coefficients（ICCs） were all more than 0.49（P0.05）,coefficient of variation（WCV） within subject was from 10.68% to 29.52%.Bland-Altman plots showed good reproducibility between the routine dose level and the low dose level for all the parameters.Conclusion It is feasible to quantitative parameter measurements at low dose CT perfusion in rabbits with implanted VX2 lung tumours.