Application Of Lower Extremity CT Angiography With Low-Dose Protocol And Iterative Model Reconstruction

Objects:To investigate the application value of low-dose protocol in combination with iterative model reconstruction(IMR)in lower extremity CT angiography(CTA).Methods:60 patients were randomly divided into group A(n=30)and group B(n=30).All the patients underwent CTA with automatic tube current modulation(ATCM).The patients in group A were scanned with 120kVp tube voltage,100 mL of contrast agent,flow rate at4 mL/s,with filtered back projection(FBP).The patients in group B were scanned with80kVp,80 mL of contrast agent,flow rate at 3mL/s,with iDOSE~4(B1)and IMR(B2).The CT values and noise of vessel were measured on bilateral lower extremity arteries of the axial images,including aortic bifurcation,common iliac bifurcation,common femoral artery,middle superficial femoral,proximal popliteal artery and tibiofibular trunk artery.The SNR and CNR were computed.The subjective quality of each segment of blood vessel image was scored on a scale of 5 points.The CTDIvol and DLP of each check were recorded.Results:The CT values of group B1 and B2 were significantly higher than that of group A(P<0.05).The SNR and CNR of group B2 were higher than those of group A and B1(P<0.05).There was no difference in subjective image quality among the three groups for aorto-iliac area and femoro-popliteal area(P>0.05).Compared with group A,The dose of CTDIvol and DLP of group B were lower(P<0.01).Conclusions:Lower extremity CTA using low-dose protocol and IMR is useful for lower radiation while preserving image quality.IMR can also provide better image quality for vessels than iDOSE~4.