The Study Of Iterative Reconstruction Technique In Low-dose CT Angiography Of Renal Artery

ObjectiveTo assess the feasibility of computed tomography angiography (CTA) in renal artery using iDose4-an iterative reconstruction technique in Brilliance iCT (Philips Ltd.).Methods90patients (body weight60-70kg) supposed to undergo renal artery CTA were selected and randomly divided into three groups:A(120kv,120mAs), B(120kv,60mAs) and C(100kv,100mAs). 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 from 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). Record each subject’s CT dose index (CTDI), CT dose length product (DLP) and calculate the effective radiation dose (ED). ResultsThe 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, the rest four parameters of group C were apparently larger, which was statistically significant (tCTvalue=-12.326,PCT value<0.001;tSNR=-7.136,PSNR<0.001;tCNR=-7.649, PCNR<0.001;ZVR=-2.690,PVR=0.007).ConclusionsImage quality is still ensured using iDose4when mAs is50%lower; and the image quality increases when radiation dose is halved at100kVp kilovoltage.