Metal Artifact Reduction in Flat-Detector CT Acquisitions of Stent-Assisted Coiled Intracranial Aneurysms

Congress:

ECR 2013

Poster Number:

C-1951

Type:

Scientific Exhibit

Keywords:

Artifacts, Aneurysms, Stents, Embolisation, Computer Applications-3D, CT-High Resolution, CT-Angiography, Cone beam CT, Neuroradiology brain, Interventional vascular, Head and neck

Authors:

P. van de Haar, D. Ruijters, J. Timmer; Best/NL

DOI:

10.1594/ecr2013/C-1951

DOI-Link:

https://dx.doi.org/10.1594/ecr2013/C-1951

Fig. 6: Axial slab in a contrast enhanced FDCT reconstruction. Left: without MAR....

Fig. 7: Zoomed 3D rendering of a contrast enhanced FDCT reconstruction. Left: without...

Fig. 8: Contrast enhanced FDCT reconstruction of a stent-assisted coiled large...

Fig. 10: Contrast enhanced FDCT reconstruction of a stent-assisted coiled aneurysm....

Purpose

In recent years the imaging capabilities of flat detector C-arm X-ray systems havebeen improved. Flat Detector Computed Tomography(FDCT) has become increasingly popular within minimally invasiveendovascular interventions [1,2]. Very recently it has becomefeasible tovisualize stents that possess very low radiopacity. The FDCT images offer the possibility to inspect the stent deployment with respect to the vessel lumen and intravascular plaques [3,4]. However, tomographic images of stents that are placed adjacent to aneurysms filled with coils areseverely distorted by streakingartifacts caused by the metal coils. In this...

Methods and Materials

VasoCT - High resolution FDCT of intracranial stents For the purpose of imaging intracranial stents and their surrounding vasculature a dedicated acquisition protocol and reconstruction settings have been developed (VasoCT; Philips Healthcare, Best, the Netherlands) [3]. The high resolution protocol consists of 620 projection images acquired over a rotational trajectory of 200°, while the imaged detector area is set to a diameter of 22 cm and using a pixel size of 0.154 mm. The X-ray tube voltage is set to 80 kV, the focal spot...

Results

Fig. 5shows a pre-interventional FDCTand a post coiling FDCTwithout and with MAR applied, in order to illustrate the MAR technique.The streaking artifacts have been reduced significantly in the reconstruction with MAR applied. Soft-tissue structures that are obstructed by the streaking artifacts origining from the coils in the aneurysm sac are clearly visible in the reconstruction with MAR. In Fig. 6a reconstruction of a coiled aneurysm is shown, while the vessels have been filled with diluted contrast medium.The second pass reconstruction (right) shows clearlythe vasculature obstructed...

Conclusion

The MAR procedure significantly reduces the presence of metal streaking artifacts caused by coils placed in aneurysms. This allows the investigation of tissue and anatomical structures adjacent to the coiled volume. In case of stent/coils combinations this is especially valuable, since the streaks tend to obscure the intracranial stent. Observers in a recent study [8] gave significantly higher scores to MAR corrected FDCT images regarding the visibility of the arteries and stents adjacent to coiled aneurysms. Especially when diluted iodine contrast medium is administrated to...

References

Söderman M, Babic D, Holmin S, Andersson T (2008): Brain imaging with a at detector C-arm, Technique and clinical interest of XperCT. Neuroradiol 50:863-868 Kamran M, Nagaraja S, Byrne JV (2010): C-arm at detector computed tomography: the technique and its applications in interventional neuro-radiology. Neuroradiol 52:319-27 Snoeren RM, Söderman M, Kroon JN, Roijers RB, de With PHN, Babic D (2012): High-resolution 3D X-ray imaging of intracranial nitinol stents. Neuroradiology 54(2):155-162 Patel NV, Gounis MJ, Wakhloo AK, Noordhoek N, Blijd J, Babic D, Takhtani D, Lee...

Personal Information

Peter van de Haar, Daniel Ruijters, Jan Timmer interventional X-Ray, Philips Healthcare, Veenpluis 4-6, 5680DA Best, the Netherlands mailto:[email protected]