Application of a Novel Metal Artifact Correction Algorithm in Flat-Panel CT After Coil Embolization of Brain Aneurysms: Intraindividual Comparison

J.-H. Buhk; M. Groth; S. Sehner; J. Fiehler; N. O. Schmidt; U. Grzyska

doi:10.1055/s-0033-1350117

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, Inhaltsverzeichnis

Rofo 2013; 185(9): 824-829
DOI: 10.1055/s-0033-1350117

Rapid Communication

Application of a Novel Metal Artifact Correction Algorithm in Flat-Panel CT After Coil Embolization of Brain Aneurysms: Intraindividual Comparison

Intraindividueller Vergleich der Anwendung eines neuen Algorithmus zur Metallartefaktkorrektur bei Flächendetektor-CT nach Coil-Embolisation von Hirnarterienaneurysmen

Authors

J.-H. Buhk

¹Dept. of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg Eppendorf, Hamburg
M. Groth

¹Dept. of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg Eppendorf, Hamburg
S. Sehner

²Dept. of Medical Biometry and Epidemiology, University Medical Center Hamburg Eppendorf, Hamburg
J. Fiehler

¹Dept. of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg Eppendorf, Hamburg
N. O. Schmidt

³Dept. of Neurosurgery, University Medical Center Hamburg Eppendorf, Hamburg
U. Grzyska

¹Dept. of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg Eppendorf, Hamburg

Abstract

Purpose: To evaluate a novel algorithm for correcting beam hardening artifacts caused by metal implants in computed tomography performed on a C-arm angiography system equipped with a flat panel (FP-CT).

Materials and Methods: 16 datasets of cerebral FP-CT acquisitions after coil embolization of brain aneurysms in the context of acute subarachnoid hemorrhage have been reconstructed by applying a soft tissue kernel with and without a novel reconstruction filter for metal artifact correction. Image reading was performed in multiplanar reformations (MPR) in average mode on a dedicated radiological workplace in comparison to the preinterventional native multisection CT (MS-CT) scan serving as the anatomic gold standard. Two independent radiologists performed image scoring following a defined scale in direct comparison of the image data with and without artifact correction. For statistical analysis, a random intercept model was calculated.

Results: The inter-rater agreement was very high (ICC = 86.3 %). The soft tissue image quality and visualization of the CSF spaces at the level of the implants was substantially improved. The additional metal artifact correction algorithm did not induce impairment of the subjective image quality in any other brain regions.

Conclusion: Adding metal artifact correction to FP-CT in an acute postinterventional setting helps to visualize the close vicinity of the aneurysm at a generally consistent image quality.

Citation Format:

Buhk JH, Groth M, Sehner S et al. Application of a Novel Metal Artifact Correction Algorithm in Flat-Panel CT After Coil Embolization of Brain Aneurysms: Intraindividual Comparison. Fortschr Röntgenstr 2013; 185: 824 – 829

Zusammenfassung

Zielsetzung: Evaluation eines neuen Rekonstruktionsalgorithmus zur Korrektur von Aufhärtungsartefakten durch metallene Implantate bei der Computertomografie an einer C-Bogen-Angiografie-Anlage mit Flächendetektoren (FD-CT).

Material und Methoden: 16 Datensätze zerebraler FD-CT Akquisitionen nach Coil-Embolisation von Hirnarterienaneurysmen im Rahmen einer akuten Subarachnoidalblutung wurden verwendet. Die Daten wurden mit einem Weichteil-Kernel zu isotropen Quellschichten rekonstruiert, jeweils mit und ohne Anwendung des neuen Rekonstruktionsfilters zur Metallartefaktreduktion. Bildbetrachtung und Auswertung erfolgten an einer radiologischen Arbeitsstation unter Verwendung multiplanarer Reformatierungen. Als anatomischer Goldstandard diente das präinterventionelle native Mehrzeilen-Computertomogramm (MS-CT). Zwei unabhängige Radiologen führten die Bildbewertung anhand einer definierten 4-Punkte-Skala durch. Die statistische Prüfung erfolgte in einem Random-Intercept-Modell.

Ergebnisse: Die Interrater-Reliabilität war sehr hoch (ICC: 86 %). Die Bewertungen für die betroffene Region waren signifikant besser unter Anwendung der Metallartefaktreduktion. Die subjektive Qualität der Darstellung der übrigen Regionen in der FD-CT wurde durch den zusätzlichen Filter nicht beeinflusst.

Schlussfolgerungen: Der neue Metallartefaktreduktionsalgorithmus ermöglicht eine verbesserte Erkennbarkeit der direkten Umgebung eines akut behandelten Aneurysmas in der FD-CT bei konstanter Gesamtqualität der Untersuchung.

Key words

brain - CT - interventional procedures - aneurysm - technical aspects

Volltext

Referenzen

References
1 Benndorf G, Strother CM, Claus B et al. Angiographic CT in cerebrovascular stenting. AJNR Am J Neuroradiol 2005; 26: 1813-1818
2 Heran NS, Song JK, Namba K et al. The utility of DynaCT in neuroendovascular procedures. AJNR Am J Neuroradiol 2006; 27: 330-332
3 Knollmann F, Valencia R, Buhk JH et al. Characteristics and applications of a flat panel computer tomography system. Fortschr Röntgenstr 2006; 178: 862-871
4 Kalender WA, Kyriakou Y. Flat-detector computed tomography (FD-CT). Eur Radiol 2007; 17: 2767-2779
5 Dorfler A, Struffert T, Engelhorn T et al. Rotational flat-panel computed tomography in diagnostic and interventional neuroradiology. Fortschr Röntgenstr 2008; 180: 891-898
6 Hausegger KA, Furstner M, Hauser M et al. Clinical application of flat-panel CT in the angio suite. Fortschr Röntgenstr 2011; 183: 1116-1122
7 Soderman M, Babic D, Holmin S et al. Brain imaging with a flat detector C-arm: Technique and clinical interest of XperCT. Neuroradiology 2008; 50: 863-868
8 Fiehler J. Unruptured brain aneurysms: when to screen and when to treat?. Fortschr Röntgenstr 2012; 184: 97-104
9 Buhk JH, Lingor P, Knauth M. Angiographic CT with intravenous administration of contrast medium is a noninvasive option for follow-up after intracranial stenting. Neuroradiology 2008; 50: 349-354
10 Richter G, Pfister M, Struffert T et al. Technical feasibility of 2D-3D coregistration for visualization of self-expandable microstents to facilitate coil embolization of broad-based intracranial aneurysms: an in vitro study. Neuroradiology 2009; 51: 851-854
11 Buhk JH, Kallenberg K, Mohr A et al. Evaluation of angiographic computed tomography in the follow-up after endovascular treatment of cerebral aneurysms--a comparative study with DSA and TOF-MRA. Eur Radiol 2009; 19: 430-436
12 Psychogios MN, Buhk JH, Schramm P et al. Feasibility of angiographic CT in peri-interventional diagnostic imaging: a comparative study with multidetector CT. AJNR Am J Neuroradiol 2010; 31: 1226-1231
13 Struffert T, Ott S, Adamek E et al. Flat-detector computed tomography in the assessment of intracranial stents: comparison with multi detector CT and conventional angiography in a new animal model. Eur Radiol 2011; 21: 1779-1787
14 Struffert T, Kloska S, Engelhorn T et al. Optimized intravenous Flat Detector CT for non-invasive visualization of intracranial stents: first results. Eur Radiol 2011; 21: 411-418
15 Psychogios MN, Wachter D, Mohr A et al. Feasibility of flat panel angiographic CT after intravenous contrast agent application in the postoperative evaluation of patients with clipped aneurysms. AJNR Am J Neuroradiol 2011; 32: 1956-1962
16 Snoeren RM, Soderman M, Kroon JN et al. High-resolution 3D X-ray imaging of intracranial nitinol stents. Neuroradiology 2012; 54: 155-162
17 Patel NV, Gounis MJ, Wakhloo AK et al. Contrast-enhanced angiographic cone-beam CT of cerebrovascular stents: experimental optimization and clinical application. AJNR Am J Neuroradiol 2011; 32: 137-144
18 Heller RS, Malek AM. Parent vessel size and curvature strongly influence risk of incomplete stent apposition in enterprise intracranial aneurysm stent coiling. AJNR Am J Neuroradiol 2011; 32: 1714-1720
19 Saake M, Struffert T, Goelitz P et al. Angiographic CT with intravenous contrast agent application for monitoring of intracranial flow diverting stents. Neuroradiology 2012; 54: 727-735
20 Golitz P, Struffert T, Ganslandt O et al. Optimized angiographic computed tomography with intravenous contrast injection: an alternative to conventional angiography in the follow-up of clipped aneurysms?. J Neurosurg 2012; 117: 29-36
21 Clarencon F, Piotin M, Pistocchi S et al. Evaluation of stent visibility by flat panel detector CT in patients treated for intracranial aneurysms. Neuroradiology 2012; 54: 1121-1125
22 Golitz P, Struffert T, Knossalla F et al. Angiographic CT with intravenous contrast injection compared with conventional rotational angiography in the diagnostic work-up of cerebral aneurysms. AJNR Am J Neuroradiol 2012; 33: 982-987
23 Ringelstein A, Schlamann M, Goericke SL et al. 3-year follow-up after endovascular aneurysm treatment with Silk(R) flow diverter. Fortschr Röntgenstr 2013; 185: 328-332
24 Doelken M, Struffert T, Richter G et al. Flat-panel detector volumetric CT for visualization of subarachnoid hemorrhage and ventricles: preliminary results compared to conventional CT. Neuroradiology 2008; 50: 517-523
25 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 2013; Epub ahead of print
26 Kamran M, Nagaraja S, Byrne JV. C-arm flat detector computed tomography: the technique and its applications in interventional neuro-radiology. Neuroradiology 2010; 52: 319-327
27 Wachter D, Psychogios M, Knauth M et al. IvACT after aneurysm clipping as an alternative to digital subtraction angiography--first experiences. Cen Eur Neurosurg 2010; 71: 121-125
28 Blanc R, Pistocchi S, Babic D et al. Intravenous flat-detector CT angiography in acute ischemic stroke management. Neuroradiology 2012; 54: 383-391
29 Prell D, Kyriakou Y, Struffert T et al. Metal artifact reduction for clipping and coiling in interventional C-arm CT. AJNR Am J Neuroradiol 2010; 31: 634-639