Ultra-low dose CT scanning in clinical practice? A preliminary study in 30 patients

Abstract

PURPOSE: To compare image quality of ultra-low dose CT scans acquired with 3 different CT reconstruction algorithms. METHODS AND MATERIALS: 30 patients who underwent standard of care CT chest/abdomen/pelvis were in addition scanned at 2 pre-selected ultra-low dose scans (noise index of 60 and 70) with images reconstructed using filtered-back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and novel model-based iterative reconstruction (MBIR). Objective and subjective image qualities were compared. Doses for each scans were recorded. Mean image noise and attenuation values were compared between different reconstruction algorithms using ANOVA with Dunnett's post-testing. RESULTS: Objective image analysis supports significant noise reduction with low dose scans using MBIR technique (p<0.05). There was no significant change in the mean CT numbers between different reconstructions or subjective image quality of ultra-low dose MBIR scans compared with standard dose scans using ASIR. Dose recorded were up to 75% lower for low dose scans. CONCLUSION: MBIR shows superior noise reduction and improved image quality. Substantial dose reduction can be achieved by increasing the noise index (manufacturer's parameters for tube current modulation for dose adjustment) as tested in this study without affecting image quality. This is a preliminary study, and part of a much larger study of which the results will be available in full at the ASM. Copyright © 2012 Published by Elsevier Ltd.