Using "iDose4" iterative reconstruction algorithm in adults' chest-abdomen-pelvis CT examinations: effect on image quality in relation to patient radiation exposure

The aim of this study is to examine the effect of iDose4 hybrid iterative reconstruction algorithm (Philips Healthcare, Cleveland, OH) on radiation dose and image quality in chest–abdomen–pelvis (CAP) CT scanning of adult patients. CAP CT examinations were performed on 99 patients with the use of the “old standard” protocol performing filtered back projection reconstruction algorithm (FBP protocol) and on 84 patients with the use of iDose4 protocol on a 64-multidetector CT. Patients were subdivided into three weight groups (Group 1, 41–60kg; Group 2, 61–90kg; and Group 3, .90kg). Volume CT dose index and dose length product (DLP) were recorded, while effective dose was calculated from DLP measurements. Objective image noise, signal-to-noise ratio and contrast-to-noise ratio were calculated. Two radiologists reviewed images to evaluate image quality. Compared with the FBP protocol, there was an overall 46.5% significant decrease in effective dose with the use of iDose4 protocol. Objective image quality was higher in iDose4 images than in FBP images. Subjective image noise, sharpness, contrast and diagnostic confidence scores tended to be better for iDose4 protocol at the decreased radiation exposure level. Artefacts were minor for both protocols. Our results suggest that the iterative acquisition protocol provides great potential for reducing radiation exposure and maintaining or improving image quality in CAP CT examinations.