Impact of a new metal artefact reduction algorithm in the noninvasive follow-up of intracranial clips, coils, and stents with flat-panel angiographic CTA: initial results

Neuroradiology. 2013 Jul;55(7):813-8. doi: 10.1007/s00234-013-1165-6. Epub 2013 Apr 16.


Introduction: Flat-panel angiographic CT after intravenous contrast agent application (ivACT) is increasingly used as a follow-up examination after coiling, clipping, or stenting. The purpose of this study was to evaluate the feasibility of a new metal artefact reduction algorithm (MARA) in patients treated for intracranial aneurysms and stenosis.

Methods: IvACT was performed on a flat-panel detector angiography system after intravenous application of 80 ml contrast media. The uncorrected raw images were transferred to a prototype reconstruction workstation where the MARA was applied. Two experienced neuroradiologists examined the corrected and uncorrected images on a commercially available workstation.

Results: Artefacts around the implants were detected in all 16 uncorrected cases, while eight cases showed remaining artefacts after correction with the MARA. In the cases without correction, there were 11 cases with "extensive" artefacts and five cases with "many" artefacts. After correction, seven cases showed "few" and only one case "many" artefacts (Wilcoxon test, P < 0.001). Parent vessels were characterized as "not identifiable" in 62% of uncorrected images, while the delineation of parent vessels were classified as "excellent" in 50% of the cases after correction (Wilcoxon test, P = 0.001).

Conclusions: Use of the MARA in our study significantly reduced artefacts around metallic implants on ivACT images and allowed for the delineation of surrounding structures.

MeSH terms

  • Aged
  • Algorithms*
  • Artifacts*
  • Blood Vessel Prosthesis
  • Cerebral Angiography / instrumentation
  • Cerebral Angiography / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Intracranial Aneurysm / diagnostic imaging*
  • Intracranial Aneurysm / surgery*
  • Male
  • Mechanical Thrombolysis / instrumentation
  • Metals
  • Middle Aged
  • Radiographic Image Enhancement / methods*
  • Radiographic Image Interpretation, Computer-Assisted / methods
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity
  • Stents*
  • Tomography, X-Ray Computed / instrumentation
  • Tomography, X-Ray Computed / methods
  • Treatment Outcome


  • Metals