A concern in the use of metallic spine fusion devices is the ability to assess local bone and soft tissue structures on imaging. Computed tomography (CT) plays an important role in the post operative evaluation of patients suspected of having metal device-related problems (1-4). However, conventional CT of patients with implants is challenging due to numerous potential artifacts related to the implanted metal. This study aims to assess the usefulness of a metal artifact CT protocol in the assessment of different fusion devices (including a...

Materials Tissue was obtained from an embalmed human cadaver bequeathed for teaching and research to the University of Auckland, New Zealand, under the acquisition of Human Tissue Act (2008). PEEK (polyetherether ketone) and porous tantulum devices (fig. 1 and 2), along with a piece of bone, were implanted in the cervical and lumbar regions.Supplemental anterior cervical fixation and posterior lumbar fixation were also performed. Dual energy CT protocol The CT examinations were performed on a 64-channel Discovery CT750 HD (GE Healthcare, Milwaukee, WI, USA). The...

There was good inter-observer correlation with a weighted kappa coefficient of 0.7703 (95% CI 0.7019 – 0.8387) for overall CT image quality and 0.7711 (95% CI 0.6879 – 0.8543) for degree of artifact. Logistic regression was used to analyse dichotomized image quality scores and also artifact scores for porous tantalum implants. Explanatory variables in the model for image artifacts included CT plane (sagittal vs. axial) and anatomic region (cervical vs. lumbar) while image type (GSI vs standard imaging) was also included in the model for...

Our results confirm that metal artifact reduction software is able to significantly reduce metal related artifacts and improve image quality on CT in both the cervical and lumbar spine. CT MARS techniques (GSI) are able to reduce the image-degrading effects of polychromatic X-rays typically utilized in conventional CT imaging through theuse of several techniques, including: virtual monochromatic spectral (VMS) imaging, simultaneous dual-energy acquisition with an extremely fast speed, and beam hardening effective energy shift. Minimal artifact was seen with both bone and the PEEK devices...

Dr Mark Macdonald, Radiology Registrar, Auckland Hospital, Auckland, New Zealand. Email address: [email protected]

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