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.