The use of iterative reconstruction technique in low-dose CT angiography of renal artery / 中华放射医学与防护杂志

ABSTRACT

Objective To assess the feasibility of computed tomography angiography (CTA) in renal artery using the iterative reconstruction technique (iDose4) in Brilliance iCT (Philips Ltd.).Methods 90 patients (body weight 60-70 kg) supposed to undergo renal artery CTA were selected and randomly divided into three groups:A(120 kV,120 mAs),B(120 kV,60 mAs) and C(100 kV,100 mAs).CTA images from Group A were obtained using filtered back projection and those from the rest groups were generated by iDose4.Then CT number of renal artery,noise (denoted as standard deviation SD),signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of images for each group were measured and recorded.Images were post-processed using volume reformation (VR) 3D imaging and image quality were assessed in five-level grade (1-5).Results The five parameters (CT number of renal artery,SD value,SNR,CNR and VR grade) of group A and group B were statistically insignificant (P ＞ 0.05).While SD values of group C were comparable to those of group A and B,the rest four parameters of group C were apparently larger,which was statistically significant (tCT value =-12.326,tSNR =-7.136,tCNR =-7.649,ZVR =-2.690,PVR ＜ 0.05).Conclusions Image quality could still fit the diagnosis requirements using iDose4 when mAs decreased lower than 50％.The image quality increases when radiation dose is halved at 100 kVp kV.