The Feasibility Study Of Evaluating The Image Quality Of Gastric Carcinoma With Iterative Model Reconstruction Technique In Low Dose Contrast-enhanced CT

PurposeTo compare the image quality among filter back-projection(FBP)、i Dose4 and iterative model reconstruction(IMR)in contrast-enhanced CT of gastric carcinoma,and to evaluate the value of clinical application of IMR combined with low-dose scans.Materials and methodsForty patients with suspicious gastric cancer in the First Affiliated Hospital of Soochow University were selected for upper abdominal CT dynamic enhanced CT scanning,Forty patients were randomly assigned into two groups(group A and group B,20 each)according to random number table.Portal scanning data of venous phase were taken as the reconstruction object.In order to ensure the quality of the image,the noise ratio of each patient was fixed.According to the different radiation dose and reconstruction algorithm,the images were divided into 6 groups: group A1(120k V,FBP),group A2(120k V,i Dose4),group A3(120k V,IMR),group B1(80k V,FBP),group B2(80k V,i Dose4,group B3(80k V,IMR).Objective evaluation indexes for image quality included image noise,signal-to-noise ratio(SNR)and contrast-to-noise(CNR).Subjective evaluation indexes for image quality included low-contrast detectability,lesion edge sharpness,image distortion and diagnostic confidence,which were assessed and compared among group A1 and A2 and A3,group B1 and B2 and B3.Effective radiation doses were calculated.ResultsEffective radiation dose in group B was reduced 73.7% compared to group A.The objective evaluation indexes for image quality included image noise with IMR were better than FBP and i Dose4,for details,The noise of A3 was decreased compared to group A1 and A2(NA3=12.9±3.2,NA2=22.7±3.3,NA1=29.0±2.7;P<0.01),The noise of B3 was decreased compared to group B1 and B2(NB3=21.2±3.0,NB2=39.7±6.4,NB1=3.2±0.6;P<0.01),The SNR of A3 was increased compared to group A1 and A2(SNRA3=16.1±3.5,SNRA2=8.8±1.1,SNRA1=5.5±0.7;P<0.01),The SNR of B3 was increased compared to group B1 and B2(SNRB3=11.6±2.3,SNRB2=5.3±1.2,SNRB1=1.7±0.6;P < 0.01),The CNR of A3 was increased compared to group A1 and A2(CNRA3=8.0±2.4,CNRA2=4.2±0.9,CNRA1=2.6±0.6;P < 0.01),The SNR of A3 was increased compared to group A1 and A2(CNRB3=6.0±1.9,CNRB2=2.7±0.8,CNRB1=1.7±0.6;P<0.01).In group A and B,the subjective evaluation indexes for image quality with IMR were better than FBP and i Dose4,and the difference between A1 and A3,B1 and B2、B3 were statistically significant.ConclusionCompared with FBP、i Dose4,IMR significantly reduces the image noise and enhances image quality of gastric carcinoma.