Experimental Research On Low Dose Renal Perfusion Imaging By MSCT

Objective To investigate the feasibility of low dose renal perfusion imaging by MSCT and its influence on perfusion parameter.Material and methods1.Animal and equipment12 healthy rabbits,weight 2.5±0.5 kg,male.SOMATOM Sensation 64 spiral CT,German SIEMENS company.Contrast agent Ultravist(300mgI/ml),MEDRAD Stellant CT 16A highpressuresyringe.2.Examination method(1)Preparation and technique Fixed the rabbit on the examination frame at dorsal decubitus after anesthetized.Perfusion scanning of left kidney was done.Selected renal hilum area level as scanning center.The syringe was connected with high-pressure syringe after the ear edge vein of the rabbit was punctured with it.Then,inject the contrast agent 2ml/kg quickly,with injection velocity 1ml/s.Scanning of lasting 60s was done after 4s given contrast agent.Scanning parameter:tube tension,100kV;layer thickness,2.4mm;pitch,2.4mm;scanning scope,26.4mm. Three different tube current(50 mAs,80 mAs,100 mAs)was respectively used to scan kidney.(2)Post-processing of renal tissue perfusion The reconstructed image was transmitted to work station and the data was processed with CT Perfusion software.The perfusion image of 20s,30s,40s,50s and 60s were analyzed with the mode of Kidney Perfusion.The functional picture and parameter of BF,BV were aquired by Perfusion software.(3)Measurement of radiation dose CT dose index(CTDIvol value)was automatically displayed on CT screen,radiation dose unit:mGy.3.Statistical analysisRepeated Measures and One Way ANOVA were adopted to compare the means of mluti-group measurement data,α=0.05.All the data was processed by SPSS 13.0 software.Results1.Overall comparison was fulfilled on the condition of three different tube current.There was no statistical difference in 20s,30,40s,50s and 60s in BF and BV value,respectively(P＞0.05). There was also no statistical difference in BF and BV on the condition of same tube current.2.There was no significant difference in BV among 50mAs,80mAs and 100mAs,respectively(P＞0.05).There was statistical difference between 100mAs and 50mAs,80mAs(P＜0.05),no difference between 50mAs and 80mAs(P＞0.05).There was no statistical difference in BF and BV when scanning time was 30s(P＞0.05). Conclusions1.Scanning time of 30s can not only observe enhanced character of renal cortex by TDC,but also satisfies the request of renal perfusion imaging,but the radiation dose received by patients markedly decreased.So,it can be a method of reducing radiaton dose gained by patients.2.When scanning time is 30s,there was no statistical difference in BF and BV aquired on the condition of 50mAs,80mAs and 100mAs,respectively.Therefore,decreasing tube current may be an effective means of reducing radiation dose.