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Original research
The impact of software-based metal artifact reduction on the liquid embolic agent Onyx in cone-beam CT: a systematic in vitro and in vivo study
  1. Niclas Schmitt1,
  2. Charlotte S Weyland1,
  3. Lena Wucherpfennig2,
  4. Christof M Sommer2,3,4,
  5. Martin Bendszus1,
  6. Markus A Möhlenbruch1,
  7. Dominik F Vollherbst1
  1. 1Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
  2. 2Department of Diagnostic and Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany
  3. 3Department of Nuclear Medicine, Heidelberg University Hospital, Heidelberg, Germany
  4. 4Clinic of Radiology and Neuroradiology, Sana Kliniken Duisburg, Duisburg, Germany
  1. Correspondence to Dr Dominik F Vollherbst, Department of Neuroradiology, Heidelberg University Hospital, INF 400, 69120 Heidelberg, Germany; dominik.vollherbst{at}


Background Onyx is frequently used for endovascular embolization of intracranial arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs). One drawback of using Onyx is the generation of artifacts in cone-beam CT (CBCT). These artifacts can represent an obstacle for the detection of periprocedural hemorrhage or planning of subsequent radiosurgery. This study investigates the effect of artifact reduction by the syngo DynaCT SMART Metal Artifact Reduction (MAR) software.

Methods A standardized in vitro tube model (n=10) was filled with Onyx 18 and CBCT image acquisition was conducted in a brain imaging phantom. Furthermore, post-interventional CBCT images of 20 patients with AVM (n=13) or dAVF (n=7), each treated with Onyx, were investigated. The MAR software was applied for artifact reduction. Artifacts of the original and the post-processed images were analyzed quantitatively (standard deviation in a region of interest on the layer providing the most artifacts) and qualitatively. For the patient images, the effect of the MAR software on brain parenchyma on artifact-free images was further investigated.

Results Quantitative and qualitative analyses of both datasets demonstrated a lower degree of artifacts in the post-processed images (eg, patient images: 38.30±22.03 density units (no MAR; mean SD±SD) vs 19.83±12.31 density units (with MAR; p<0.001). The MAR software had no influence on the brain parenchyma in artifact-free images.

Conclusion The MAR software significantly reduced the artifacts evoked by Onyx in CBCT without affecting the visualization of brain parenchyma on artifact-free images. Applying this software could thus improve the quality of periprocedural CBCT images after embolization with Onyx.

  • CT
  • intervention
  • liquid embolic material
  • vascular malformation
  • angiography

Data availability statement

All data relevant to the study are included in the article or uploaded as supplemental information.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplemental information.

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  • Contributors NSCH, MB, MAM and DFV initiated the project. NSCH and DFV led the research, conducted the retrospective data acquisition, statistical analysis and wrote the manuscript. MB, MAM and DFV were involved in the study design and concept. CSW, LW and CMS participated in data acquisition. All authors discussed the results, commented on the paper, and approved the final version of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.