Evaluation of computed tomography artefacts of carbon-fiber and titanium implants in patients with spinal oligometastatic disease undergoing stereotactic ablative radiotherapy

This study evaluated artefacts on computed tomography (CT) images using Hounsfield units (HU) in patients with spinal oligometastatic disease who received carbon-fiber (CF; n = 11) or titanium (n = 11) spine implants and underwent stereotactic ablative radiotherapy (SABR). Significant differences in HU were observed at the vertebral body, the pedicle, and the spinal cord at the lowest instrumented vertebra level for both CF and titanium (average increase 1.54-fold and 5.11-fold respectively). The relatively high postoperative HU-increase after insertion of titanium implants indicated CT artefacts, while the relatively low HU-increase of CF implants was not associated with artefacts.

• 1
  Significant increases in Hounsfield units (HU) were observed at the vertebral body, pedicle, and spinal cord at the lowest instrumented vertebra level for both carbon-fiber (CF) and titanium implants.
• 2
  At the metastatic spinal cord compression level, a trend towards a higher HU-increase was observed in titanium implants compared with CF implants.
• 3
  A CT artefact grading system based on postoperative HU-increase is proposed, which provides information on the ability to assess anatomically relevant structures.