Article ID Journal Published Year Pages File Type
4225350 European Journal of Radiology 2014 8 Pages PDF
Abstract

•We compared virtual monochromatic spectral (VMS) images with 120-kVp images.•VMS images are generated using accurate two-material beam-hardening correction.•Abdominal 70-keV VMS images provide better image quality than 120-kVp images.•Iterative reconstruction can further improve the image quality of VMS images.

ObjectivesTo compare quantitative and subjective image quality between virtual monochromatic spectral (VMS) and conventional polychromatic 120-kVp imaging performed during the same abdominal computed tomography (CT) examination.Materials and methodsOur institutional review board approved this prospective study; each participant provided written informed consent. 51 patients underwent sequential fast kVp-switching dual-energy (80/140 kVp, volume CT dose index: 12.7 mGy) and single-energy (120-kVp, 12.7 mGy) abdominal enhanced CT over an 8 cm scan length with a random acquisition order and a 4.3-s interval. VMS images with filtered back projection (VMS-FBP) and adaptive statistical iterative reconstruction (so-called hybrid IR) (VMS-ASIR) (at 70 keV), as well as 120-kVp images with FBP (120-kVp-FBP) and ASIR (120-kVp-ASIR), were generated from dual-energy and single-energy CT data, respectively. The objective image noises, signal-to-noise ratios and contrast-to-noise ratios of the liver, kidney, pancreas, spleen, portal vein and aorta, and the lesion-to-liver and lesion-to-kidney contrast-to-noise ratios were measured. Two radiologists independently and blindly assessed the subjective image quality. The results were analyzed using the paired t-test, Wilcoxon signed rank sum test and mixed-effects model with Bonferroni correction.ResultsVMS-ASIR images were superior to 120-kVp-FBP, 120-kVp-ASIR and VMS-FBP images for all the quantitative assessments and the subjective overall image quality (all P < 0.001), while VMS-FBP images were superior to 120-kVp-FBP and 120-kVp-ASIR images (all P < 0.004).ConclusionsVMS images at 70 keV have a higher image quality than 120-kVp images, regardless of the application of hybrid IR. Hybrid IR can further improve the image quality of VMS imaging.

Related Topics
Health Sciences Medicine and Dentistry Radiology and Imaging
Authors
, , , , , ,