Low-dose CT imaging of a total hip arthroplasty phantom using model-based iterative reconstruction and orthopedic metal artifact reduction

R. H. H. Wellenberg, M. F. Boomsma, J. A. C. van Osch, A. Vlassenbroek, J. Milles, M. A. Edens, G. J. Streekstra, C. H. Slump, M. Maas

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Abstract

To compare quantitative measures of image quality, in terms of CT number accuracy, noise, signal-to-noise-ratios (SNRs), and contrast-to-noise ratios (CNRs), at different dose levels with filtered-back-projection (FBP), iterative reconstruction (IR), and model-based iterative reconstruction (MBIR) alone and in combination with orthopedic metal artifact reduction (O-MAR) in a total hip arthroplasty (THA) phantom. Scans were acquired from high- to low-dose (CTDIvol: 40.0, 32.0, 24.0, 16.0, 8.0, and 4.0 mGy) at 120- and 140- kVp. Images were reconstructed using FBP, IR (iDose(4) level 2, 4, and 6) and MBIR (IMR, level 1, 2, and 3) with and without O-MAR. CT number accuracy in Hounsfield Units (HU), noise or standard deviation, SNRs, and CNRs were analyzed. The IMR technique showed lower noise levels (p  < 0.01), higher SNRs (p  < 0.001) and CNRs (p  < 0.001) compared with FBP and iDose(4) in all acquisitions from high- to low-dose with constant CT numbers. O-MAR reduced noise (p  < 0.01) and improved SNRs (p  < 0.01) and CNRs (p  < 0.001) while improving CT number accuracy only at a low dose. At the low dose of 4.0 mGy, IMR level 1, 2, and 3 showed 83%, 89%, and 95% lower noise values, a factor 6.0, 9.2, and 17.9 higher SNRs, and 5.7, 8.8, and 18.2 higher CNRs compared with FBP respectively. Based on quantitative analysis of CT number accuracy, noise values, SNRs, and CNRs, we conclude that the combined use of IMR and O-MAR enables a reduction in radiation dose of 83% compared with FBP and iDose(4) in the CT imaging of a THA phantom
Original languageEnglish
Pages (from-to)623-632
JournalSkeletal Radiology
Volume46
Issue number5
Early online date2017
DOIs
Publication statusPublished - 1 May 2017

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