Abstract
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.
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Acknowledgments
The department has a Research Agreement with Siemens AG, Forchheim, Germany.
Conflict of interest
MNP has received support from Siemens AG (money paid to institution) for basic flight and hotel accommodation expenses for RSNA 2011, Chicago, and ASNR 2012, New York. PS and MK have received speaker's honoraria from Siemens AG. BS and YK are employees of Siemens AG. CR consults for Siemens AG.
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This paper was first presented during the ASNR 50th Annual Meeting & The Foundation of the ASNR Symposium 2012, New York, April 21-26, 2012.
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Psychogios, MN., Scholz, B., Rohkohl, C. et al. 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 55, 813–818 (2013). https://doi.org/10.1007/s00234-013-1165-6
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DOI: https://doi.org/10.1007/s00234-013-1165-6