Effect of different CT scanners and settings on femoral failure loads calculated by finite element models

Florieke Eggermont*, Loes C Derikx, Jeffrey Free, Ruud van Leeuwen, Yvette M van der Linden, Nico Verdonschot, Esther Tanck

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    10 Citations (Scopus)
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    Abstract

    In a multi-center patient study, using different CT scanners, CT-based finite element (FE) models are utilized to calculate failure loads of femora with metastases. Previous studies showed that using different CT scanners can result in different outcomes. This study aims to quantify the effects of (i) different CT scanners; (ii) different CT protocols with variations in slice thickness, field of view (FOV), and reconstruction kernel; and (iii) air between calibration phantom and patient, on Hounsfield Units (HU), bone mineral density (BMD), and FE failure load. Six cadaveric femora were scanned on four CT scanners. Scans were made with multiple CT protocols and with or without an air gap between the body model and calibration phantom. HU and calibrated BMD were determined in cortical and trabecular regions of interest. Non-linear isotropic FE models were constructed to calculate failure load. Mean differences between CT scanners varied up to 7% in cortical HU, 6% in trabecular HU, 6% in cortical BMD, 12% in trabecular BMD, and 17% in failure load. Changes in slice thickness and FOV had little effect (4%), while reconstruction kernels had a larger effect on HU (16%), BMD (17%), and failure load (9%). Air between the body model and calibration phantom slightly decreased the HU, BMD, and failure loads (8%). In conclusion, this study showed that quantitative analysis of CT images acquired with different CT scanners, and particularly reconstruction kernels, can induce relatively large differences in HU, BMD, and failure loads. Additionally, if possible, air artifacts should be avoided. (c) 2018 Orthopaedic Research Society. (c) 2018 The Authors. Journal of Orthopaedic Research (R) Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 36:2288-2295, 2018.

    Original languageEnglish
    Pages (from-to)2288-2295
    Number of pages8
    JournalJournal of Orthopaedic Research
    Volume36
    Issue number8
    DOIs
    Publication statusPublished - Aug-2018

    Keywords

    • CT scanner
    • CT protocol
    • finite element model
    • femur
    • failure load
    • METASTATIC LESIONS
    • RANDOMIZED-TRIAL
    • STRENGTH
    • FRACTURE
    • PREDICTIONS
    • PHANTOM
    • VALUES
    • RISK

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