RESUMO
Objective To evaluate the image quality improvement on abdominal CT imaging by using new model-based iterative reconstruction (MBIRn)in comparison with adaptive statistical iterative reconstruction (ASiR).Methods 40 patients who underwent upper abdominal three-phase contrast-enhanced scan were included.After scanning,all the scans obtained at 180 s later injection were reconstructed by three protocol,including ASiR (combined reconstruction of 40%FBP and 60%ASiR),the MBIRn of the noise reduction settings (MBIRNR40)and the spatinal resolution settings(MBIRSTND).The thickness of the slice was 0.625 mm.The values of CT and SD of the subcutaneous fat,left erector spinae,inferior vena cava and hepatic vein (left and right branches)were measured at the branch level of hepatic vein,and the contrast noise ratio (CNR)between inferior vena cava and hepatic vein were calculated.The subj ective image quality was evaluated by two radiologists according to the noise,smoothness and small branches of the inferior vena cava and hepatic vein using 5-scoring method.The quality images obtained from ASiR method were treated as reference standard.Results For MBIRSTNDand MBIRNR40images,the subjective noise decreased and image quality increased comparing with ASiR images.Among which the MBIRNR40images had the best image with vascular smoothness score and the lowest subjective noise.Conclusion Compared with ASiR,MBIRSTNDand MBIRNR40,especially MBIRNR40improves the quality of CT images of the inferior vena cava and its branches.