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Fairly direct hit! Advances in imaging of shotgun projectiles in MRI

Eggert, Sebastian ; Kubik-Huch, Rahel ; Klarhöfer, Markus ; Peters, Alexander ; Bolliger, Stephan ; Thali, Michael ; Anderson, Suzanne ; Froehlich, Johannes

In: European Radiology, 2015, vol. 25, no. 9, p. 2745-2753

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    Titre
    • Fairly direct hit! Advances in imaging of shotgun projectiles in MRI
    Auteur
    • Eggert, Sebastian. Department of Radiology, Kantonsspital Baden AG, Im Ergel, 5404, Baden, Switzerland
    • Kubik-Huch, Rahel. Department of Radiology, Kantonsspital Baden AG, Im Ergel, 5404, Baden, Switzerland
    • Klarhöfer, Markus. Siemens Healthcare, Zurich, Switzerland
    • Peters, Alexander. Department of Radiology, Kantonsspital Baden AG, Im Ergel, 5404, Baden, Switzerland
    • Bolliger, Stephan. Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
    • Thali, Michael. Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
    • Anderson, Suzanne. Department of Radiology, Kantonsspital Baden AG, Im Ergel, 5404, Baden, Switzerland
    • Froehlich, Johannes. Federal Institute of Technology, Pharmaceutical Sciences, Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • European Radiology, 2015, vol. 25, no. 9, p. 2745-2753. Springer Berlin Heidelberg
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:331983
    Summary
    Objectives: To investigate the magnetic properties of different types of projectiles and qualify the metal artefact reduction technique for diagnostic and/or forensic MRI. Materials and methods: Ten different projectiles embedded in ordnance gelatine blocks underwent an in vitro 1.5-T MR study with seven sequences including a recently developed metal artefact reduction sequence (Advanced WARP) combining VAT (view-angle-tilting) and SEMAC (slice-encoding metal-artefact-correction). Resulting image quality (five-point scale: 1=best; 5=worst) was scored. Quantifiable magnetic characteristics were correlated with qualitative rating of the MR sequences and torque dislodgment. Results: Metal artefact reduction sequence (median: 2.5) significantly (p < 0.001) improves depiction of projectiles in comparison to all other MR pulse sequences (median: 4.75). Images from diamagnetic composed bullets (median: 2) are much less disturbed compared to magnetic attracted ones (median: 5). Correlation (0.623) between deflection angle measurement (ferromagnetic mean 84.2°; paramagnetic 62°; diamagnetic mean 0°) and median qualitative image quality was highly significant (p = 0.027). Torque dislodgement was distinct for elongated magnetic attracted projectiles. Conclusions: Significant improvement of MR imaging of projectiles using metal artefact reduction techniques has important implications for diagnostic/forensic work-up. The correlations between magnetic attraction force, deflection-angle results and image properties demonstrate that the MR safety of projectiles can be estimated with one of these methods. Key Points : • Metal artefact reduction sequence improves overall image quality of bullets (p < 0.001). • Deflection angle assessment significantly predicts image quality of bullets (p = 0.027). • Classification of projectiles' magnetic properties based on artefacts' characteristics is possible. • Classifying of bullets has important implications in diagnostic and forensic imaging. • Identification of projectiles' magnetic attributes improves estimation of patients' injury risk.