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Can E, Böning G, Lüdemann WM, Hosse C, Kolck J, Paparoditis S, Nguyen T, Piper SK, Geisel D, Wieners G, Gebauer B, Elkilany A, Jonczyk M. Evaluation of a prototype metal artifact reduction algorithm for cone beam CT in patients undergoing radioembolization. Sci Rep 2024; 14:16399. [PMID: 39014057 PMCID: PMC11252118 DOI: 10.1038/s41598-024-66978-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Accepted: 07/06/2024] [Indexed: 07/18/2024] Open
Abstract
Metal artifacts notoriously pose significant challenge in computed tomography (CT), leading to inaccuracies in image formation and interpretation. Artifact reduction tools have been designed to improve cone beam computed tomography (CBCT) image quality by reducing artifacts caused by certain high-density materials. Metal artifact reduction (MAR) tools are specific algorithms that are applied during image reconstruction to minimize or eliminate artifacts degrading CBCT images. The purpose of the study is to evaluate the effect of a MAR algorithm on image quality in CBCT performed for evaluating patients before transarterial radioembolization (TARE). We retrospectively included 40 consecutive patients (aged 65 ± 13 years; 23 males) who underwent 45 CBCT examinations (Allura FD 20, XperCT Roll protocol, Philips Healthcare, Best, The Netherlands) in the setting of evaluation for TARE between January 2017 and December 2018. Artifacts caused by coils, catheters, and surgical clips were scored subjectively by four readers on a 5-point scale (1 = artifacts affecting diagnostic information to 5 = no artifacts) using a side-by-side display of uncorrected and MAR-corrected images. In addition, readers scored tumor visibility and vessel discrimination. MAR-corrected images were assigned higher scores, indicating better image quality. The differences between the measurements with and without MAR were most impressive for coils with a mean improvement of 1.6 points (95%CI [1.5 1.8]) on the 5-point likert scale, followed by catheters 1.4 points (95%CI [1.3 1.5]) and clips 0.7 points (95%CI [0.3 1.1]). Improvements for other artifact sources were consistent but relatively small (below 0.25 points on average). Interrater agreement was good to perfect (Kendall's W coefficient = 0.68-0.95) and was higher for MAR-corrected images, indicating that MAR improves diagnostic accuracy. A metal artifact reduction algorithm can improve diagnostic and interventional accuracy of cone beam CT in patients undergoing radioembolization by reducing artifacts caused by diagnostic catheters and coils, lowering interference of metal artifacts with adjacent major structures, and improving tumor visibility.
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Affiliation(s)
- Elif Can
- Department of Diagnostic and Interventional Radiology, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
| | - Georg Böning
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Willie Magnus Lüdemann
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Clarissa Hosse
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Johannes Kolck
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Sophia Paparoditis
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Thao Nguyen
- Institute of Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Sophie K Piper
- Institute of Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Dominik Geisel
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Gero Wieners
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Bernhard Gebauer
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Aboelyazid Elkilany
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Martin Jonczyk
- Department of Diagnostic and Interventional Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
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Kashima K, Fukushima Y. [Evaluation of the Effect of Tube Voltage on Metal Artifact Reduction in Cone Beam Computed Tomography]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2022; 78:726-731. [PMID: 35691916 DOI: 10.6009/jjrt.2022-1167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The purpose of this study was to evaluate the effectiveness of metal artifact reduction (MAR) processing in cone beam computed tomography angiography using the relative artifact index (AIr) and the difference due to tube voltage. A water phantom was imaged to obtain noise images. Next, a platinum alloy embolic coil was installed in the central part of the water phantom and the peripheral part, and then artifact images were acquired. The tube voltages were 70 kV and 109 kV, and four types of artifact images were acquired (with and without MAR). In all, 10 images in the z-direction from each image series were acquired (total: 40 images). The AIr value was calculated by setting a region of interest in the images, and multiple comparisons were made between the imaging conditions (significance level set at p<0.05). The AIr values were significantly lower by MAR, and MAR significantly reduced metal artifacts regardless of tube voltage (p<0.001). This study's results show that MAR with cone beam CT can reduce metal artifacts by more than 91%, and the effect is comparable regardless of tube voltage.
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Affiliation(s)
| | - Yasuhiro Fukushima
- Clinical Radiology Service Unit, Kyoto University Hospital (Current address: Department of Applied Medical Imaging, Gunma University Graduate School of Medicine)
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Clinical Evaluation of an Innovative Metal-Artifact-Reduction Algorithm in FD-CT Angiography in Cerebral Aneurysms Treated by Endovascular Coiling or Surgical Clipping. Diagnostics (Basel) 2022; 12:diagnostics12051140. [PMID: 35626296 PMCID: PMC9140112 DOI: 10.3390/diagnostics12051140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/28/2022] [Accepted: 05/02/2022] [Indexed: 02/01/2023] Open
Abstract
Treated cerebral aneurysms (IA) require follow-up imaging to ensure occlusion. Metal artifacts complicate radiologic assessment. Our aim was to evaluate an innovative metal-artifact-reduction (iMAR) algorithm for flat-detector computed tomography angiography (FD-CTA) regarding image quality (IQ) and detection of aneurysm residua/reperfusion in comparison to 2D digital subtraction angiography (DSA). Patients with IAs treated by endovascular coiling or clipping underwent both FD-CTA and DSA. FD-CTA datasets were postprocessed with/without iMAR algorithm (MAR+/MAR−). Evaluation of all FD-CTA and DSA datasets regarding qualitative (IQ, MAR) and quantitative (coil package diameter/CPD) parameters was performed. Aneurysm occlusion was assessed for each dataset and compared to DSA findings. In total, 40 IAs were analyzed (ncoiling = 24; nclipping = 16). All iMAR+ datasets demonstrated significantly better IQ (pIQ coiling < 0.0001; pIQ clipping < 0.0001). iMAR significantly reduced the metal-artifact burden but did not affect the CPD. iMAR significantly improved the detection of aneurysm residua/reperfusion with excellent agreement with DSA (naneurysm detection MAR+/MAR−/DSA = 22/1/26). The iMAR algorithm significantly improves IQ by effective reduction of metal artifacts in FD-CTA datasets. The proposed algorithm enables reliable detection of aneurysm residua/reperfusion with good agreement to DSA. Thus, iMAR can help to reduce the need for invasive follow-up in treated IAs.
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Fujimura S, Brehm A, Takao H, Uchiyama Y, Karagiozov K, Fukudome K, Yamamoto M, Murayama Y, Psychogios MN. Hemodynamic Characteristics and Clinical Outcome for Intracranial Aneurysms treated with the Derivo Embolization Device, a Novel Second-Generation Flow Diverter. World Neurosurg 2021; 159:e252-e259. [PMID: 34929366 DOI: 10.1016/j.wneu.2021.12.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/10/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND PURPOSE We investigated the relationship between hemodynamic characteristics and clinical outcomes for aneurysms treated by the Derivo Embolization Device (DED), a novel second-generation Flow-Diverter Stent, using computational fluid dynamics (CFD). MATERIALS AND METHODS Data were retrospectively obtained from two centers between 2017 and 2019. During the period, 23 patients were treated for 23 aneurysms with DED. In 17 patients we were able to conduct CFD analysis as six were excluded due to pre-coiling, unsuitable arterial geometry, and complex geometric form. Aneurysm occlusion was rated with the O`Kelly-Marotta (OKM) grading scale on DSA 6 months after stent placement in all patients. Hemodynamic and morphological parameters were statistically compared between two groups: with full occlusion and with a remnant. RESULTS Full occlusion was observed in 17 out of 23 (73.9%) patients. In the group suitable for CFD analysis, we observed 13 fully occluded aneurysms and 4 with any remnant (specifically 1 OKM C, 1 B and 2 A). The energy loss per volume (ELV), which indicates the energy loss through the aneurysm, was significantly larger in pre and post stenting (p<.05) in the complete occlusion cases. In addition, the inflow concentration index (ICI) and inflow area ratio (IAR) of the remnant cases were significantly larger and lower, respectively (p<.05). CONCLUSION Our CFD results indicate that the energy loss involved with the blood flow passing through an aneurysm and concentrated inflow into aneurysm were the most important factors to determine whether an aneurysm will become a complete occlusion or remnant case.
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Affiliation(s)
- Soichiro Fujimura
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Alex Brehm
- Department of Neuroradiology, Clinic for Radiology & Nuclear Medicine, University Hospital Basel, Basel, Switzerland
| | - Hiroyuki Takao
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yuya Uchiyama
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kostadin Karagiozov
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Koji Fukudome
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Marios-Nikos Psychogios
- Department of Neuroradiology, Clinic for Radiology & Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
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Schmitt N, Weyland CS, Wucherpfennig L, Sommer CM, Bendszus M, Möhlenbruch MA, Vollherbst DF. 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. J Neurointerv Surg 2021; 14:832-836. [PMID: 34433643 PMCID: PMC9304113 DOI: 10.1136/neurintsurg-2021-018018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 08/15/2021] [Indexed: 11/29/2022]
Abstract
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.
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Affiliation(s)
- Niclas Schmitt
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Charlotte S Weyland
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Lena Wucherpfennig
- Department of Diagnostic and Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Christof M Sommer
- Department of Diagnostic and Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany.,Department of Nuclear Medicine, Heidelberg University Hospital, Heidelberg, Germany.,Clinic of Radiology and Neuroradiology, Sana Kliniken Duisburg, Duisburg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Markus A Möhlenbruch
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Dominik F Vollherbst
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
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Metal artifact reduction algorithm for image quality improvement of cone-beam CT images of medium or large cerebral aneurysms treated with stent-assisted coil embolization. Neuroradiology 2019; 62:89-96. [PMID: 31701181 DOI: 10.1007/s00234-019-02297-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/23/2019] [Indexed: 11/27/2022]
Abstract
PURPOSE The aim of the present study was to assess image quality improvement using a metal artifact reduction (MAR) algorithm in cases of medium or large cerebral aneurysms treated with stent-assisted coil embolization (SAC), and to analyze factors associated with the usefulness of the MAR algorithm. METHODS We retrospectively evaluated the cone-beam computed tomography (CBCT) data sets of 18 patients with cerebral aneurysms treated with SAC. For subjective analysis, images of all cases with and without MAR processing were evaluated by five neurosurgeons based on four criteria using a five-point scale. For objective analysis, the CT values of all cases with and without MAR processing were calculated. In addition, we assessed factors associated with the usefulness of the MAR by analyzing the nine cases in which the median score for criterion 1 improved by more than two points. RESULTS MAR processing improved the median scores for all four criteria in 17/18 cases (94.4%). Mean CT values of the region of interest at the site influenced by metal artifacts were significantly reduced after MAR processing. The maximum diameter of the coil mass (< 17 mm; odds ratio [OR], 4.0; 95% confidence interval [CI], 1.2-13.9; p = 0.02) and vessel length covered by metal artifacts (< 24 mm; OR, 2.3; 95% CI, 1.1-4.7; p = 0.03) was significantly associated with the usefulness of the MAR. CONCLUSIONS This study suggests the feasibility of a MAR algorithm to improve the image quality of CBCT images in patients who have undergone SAC for medium or large aneurysms.
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Amelung N, Maus V, Behme D, Papageorgiou IE, Leyhe JR, Knauth M, Psychogios MN. Evaluation of an optimized metal artifact reduction algorithm for flat-detector angiography compared to DSA imaging in follow-up after neurovascular procedures. BMC Med Imaging 2019; 19:66. [PMID: 31412810 PMCID: PMC6694691 DOI: 10.1186/s12880-019-0352-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/23/2019] [Indexed: 11/18/2022] Open
Abstract
Background Flat detector CT – angiography (FDCTA) has become a valuable imaging tool in post- and peri-interventional imaging after neurovascular procedures. Metal artifacts produced by radiopaque implants like clips or coils still impair image quality. Methods FDCTA was performed in periprocedural or follow-up imaging of 21 patients, who had received neurovascular treatment. Raw data was sent to a dedicated workstation and subsequently a metal artifact reduction algorithm (MARA) was applied. Two neuroradiologists examined the images. Results Application of MARA improved image appearance and led to a significant reduction of metal artifacts. After application of MARA only 8 datasets (34% of the images) were rated as having many or extensive artifacts, before MARA 15 (65%) of the images had extensive or many artifacts. Twenty percent more cases of reperfusion were diagnosed after application of MARA, congruent to the results of digital subtraction angiography (DSA) imaging. Also 3 (13% of datasets) images, which could not be evaluated before application of MARA, could be analyzed after metal artifact reduction and reperfusion could be excluded. Conclusion Application of MARA improved image evaluation, reduced the extent of metal artifacts, and more cases of reperfusion could be detected or excluded, congruent to DSA imaging.
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Affiliation(s)
- Nadine Amelung
- Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany.
| | - Volker Maus
- Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany
| | - Daniel Behme
- Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany
| | - Ismini E Papageorgiou
- Institute for Diagnostic and Interventional Radiology, University Hospital of Jena, Am Klinikum 1, 07747, Jena, Germany.,Institute for Radiology, Südharz Klinikum Nordhausen, Dr. Robert Koch Straße 39, 99734, Nordhausen, Germany
| | - Johanna Rosemarie Leyhe
- Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany
| | - Michael Knauth
- Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany
| | - Marios Nikos Psychogios
- Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany
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Application of a Metal Artifact Reduction Algorithm for C-Arm Cone-Beam CT: Impact on Image Quality and Diagnostic Confidence for Bronchial Artery Embolization. Cardiovasc Intervent Radiol 2019; 42:1449-1458. [PMID: 31321481 DOI: 10.1007/s00270-019-02286-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/18/2019] [Accepted: 07/05/2019] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The objective of this study was to evaluate the potential benefit of a dedicated cone-beam-CT streak metal artifact removal technique (SMART) in terms of both image quality and diagnostic confidence in patients undergoing bronchial artery embolization. METHODS A total of 17 patients were included in this retrospective study. The SMART algorithm was applied to images containing streak artifacts generated by a radiopaque intra-arterial catheter tip. Quantitative evaluation of artifact severity was performed via measurement of the Hounsfield units along a closed loop surrounding the catheter tip and was conducted in the frequency domain following the application of the discrete Fourier transform to the measured data. A high proportion of power in the low frequencies of the resulting spectrum indicated a high level of streak artifacts. Qualitative evaluation of diagnostic confidence was performed using a 4-point Likert scale. RESULTS Both quantitative and qualitative evaluation demonstrated a significant reduction in artifact severity using the SMART algorithm. Quantitative evaluation demonstrated a mean artifact reduction of 22.5% using SMART compared to non-SMART images (p < 0.001). Qualitative evaluation demonstrated the greatest artifact reduction at the inner and outer aortic curvature, as well as immediately surrounding the tip of the catheter. In 6 of 17 cases, the use of the SMART algorithm yielded additional clinical information, increasing mean diagnostic confidence from 3.17 to 3.78 (p < 0.001). CONCLUSION The SMART algorithm allows for efficient reduction of metal artifacts introduced by radiopaque catheter tips during cone-beam CT. Using this algorithm, diagnostic images of the aortic arch were significantly improved both quantitatively and qualitatively, yielding clinically relevant levels of enhanced diagnostic confidence. These results demonstrate that the SMART algorithm improves diagnostic and clinical characterization of the course of bronchial arteries on CBCT images, potentially improving the accuracy and clinical efficacy of bronchial artery embolization. LEVEL OF EVIDENCE 3.
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Kuroda H, Toyota S, Kumagai T, Iwata T, Kobayashi M, Mori K, Taki T. Feasibility of Smart Metal Artifact Reduction Algorithm on Computed Tomography Angiography for Clipping of Recurrent Aneurysms After Coil Embolization. World Neurosurg 2019; 127:e1249-e1254. [PMID: 31026660 DOI: 10.1016/j.wneu.2019.04.133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 04/14/2019] [Accepted: 04/15/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND The number of patients with a history of clipping of recurrent aneurysms after coil embolization has increased. The aim of this article was to report the feasibility of CT angiography using a commercial metal artifact reduction algorithm (Smart Metal Artifact Reduction [MAR]) for patients who underwent clipping of recurrent aneurysms after coil embolization. METHODS Six cases of clipping of recurrent aneurysms after coil embolization were examined with CT angiography using MAR between 2015 and 2018 at a single institution. Conventional CT angiography and three-dimensional digital subtraction angiography data were compared, and depiction of the status of treated aneurysms using MAR was estimated. RESULTS Conventional CT angiography was unable to depict the status of treated aneurysms in the patients with a history of clipping of recurrent aneurysms after coil embolization because of metal artifacts. With MAR, metal artifacts were greatly reduced, and the status of treated aneurysms was able to be depicted, although depiction was inferior to three-dimensional digital subtraction angiography. CONCLUSIONS For patients with a history of clipping of recurrent aneurysms after coil embolization, CT angiography using MAR is feasible, although further development of imaging techniques is needed.
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Affiliation(s)
- Hideki Kuroda
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan
| | - Shingo Toyota
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan.
| | - Tetsuya Kumagai
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan
| | - Takamitsu Iwata
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan
| | - Maki Kobayashi
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan
| | - Kanji Mori
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan
| | - Takuyu Taki
- Department of Neurosurgery, Kansai Rosai Hospital, Hyogo, Japan
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An Unusual Case of Perforating Injury to the Middle Ear and Temporal Bone. Otol Neurotol 2018; 39:e1174-e1175. [PMID: 30444853 DOI: 10.1097/mao.0000000000002042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Katsura M, Sato J, Akahane M, Tajima T, Furuta T, Mori H, Abe O. Single-energy metal artifact reduction technique for reducing metallic coil artifacts on post-interventional cerebral CT and CT angiography. Neuroradiology 2018; 60:1141-1150. [PMID: 30143820 DOI: 10.1007/s00234-018-2081-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/14/2018] [Indexed: 12/22/2022]
Abstract
PURPOSE To evaluate the effects of the single-energy metal artifact reduction (SEMAR) algorithm on image quality of cerebral CT and CT angiography (CTA) for patients who underwent intracranial aneurysm coiling. METHODS Twenty patients underwent cerebral CT and CTA using a 320-detector row CT after intracranial aneurysm coiling. Images with and without application of the SEMAR algorithm (SEMAR CT and standard CT images, respectively) were reconstructed for each patient. The images were qualitatively assessed by two independent radiologists in a blinded manner for the depiction of anatomical structures around the coil, delineation of the arteries around the coil, and the depiction of the status of coiled aneurysms. Artifact strength was quantitatively assessed by measuring the standard deviation of attenuation values around the coil. RESULTS The strength of artifacts measured in SEMAR CT images was significantly lower than that in standard CT images (25.7 ± 10.2 H.U. vs. 80.4 ± 67.2 H.U., p < 0.01, Student's paired t test). SEMAR CT images were significantly improved compared with standard CT images in the depiction of anatomical structures around the coil (p < 0.01, the sign test), delineation of the arteries around the coil (p < 0.01), and the depiction of the status of coiled aneurysms (p < 0.01). CONCLUSION The SEMAR algorithm significantly reduces metal artifacts from intracranial aneurysm coiling and improves visualization of anatomical structures and arteries around the coil, and depiction of the status of coiled aneurysms on post-interventional cerebral CT.
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Affiliation(s)
- Masaki Katsura
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
| | - Jiro Sato
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Masaaki Akahane
- Department of Radiology, School of Medicine, International University of Health and Welfare, Chiba, Japan
| | - Taku Tajima
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Toshihiro Furuta
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Harushi Mori
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
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Zhang Q, Zhao H, Sun Q, Han J, Zhang H, Shan T, Pan W, Gu C, Xu R, Mao G. Clinical evaluation of volume of interest imaging combined with metal artifact reduction reconstruction techniques in coiling and stent assisted coiling during neurointerventional procedures. J Neurointerv Surg 2018; 11:205-210. [DOI: 10.1136/neurintsurg-2018-013886] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/06/2018] [Accepted: 06/06/2018] [Indexed: 11/03/2022]
Abstract
PurposeThree-dimensional (3D) scans with flat detector angiographic systems are widely used for neurointerventions by providing detailed vascular information. However, its associated radiation dose and streak metal artifact generated by implanted treatment devices remain issues. This work evaluates the feasibility and clinical value of volume of interest imaging combined with metal artifact reduction (VOI+MAR) to generate high quality 3D images with reduced radiation dose and metal artifacts.Material and methodsFull volume (FV) and VOI scans were acquired in 25 patients with intracranial aneurysms and treated with either endovascular coiling (n=9) or stent assisted coiling (n=16) procedures. FV and VOI scans were reconstructed with conventional syngo DynaCT and VOI +MAR prototype software, respectively.ResultsQuantitative evaluation results demonstrated that compared with standard FV syngo DynaCT images, overall image quality was improved in the VOI+MAR reconstructed images, with streak metal artifacts considerably reduced or even removed; details of soft tissue in the vicinity of the metal devices was well preserved or recovered in the majority of cases. Radiation dose to patients calculated by dose area product was found to be significantly reduced using VOI scans.ConclusionThis study confirmed the feasibility of using VOI+MAR prototype software to achieve high image quality of a small volume of clinical interest and to reduce radiation dose. This technique has potential to improve patient safety and treatment outcomes.
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Fitsiori A, Martin SP, Juillet De Saint Lager A, Gariani J, Lovblad KO, Montet X, Vargas MI. Iterative Algorithms Applied to Treated Intracranial Aneurysms. Clin Neuroradiol 2018; 29:741-749. [DOI: 10.1007/s00062-018-0701-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/31/2018] [Indexed: 12/25/2022]
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Sunwoo L, Park SW, Rhim JH, Kang Y, Chung YS, Son YJ, Kim SC. Metal Artifact Reduction for Orthopedic Implants: Brain CT Angiography in Patients with Intracranial Metallic Implants. J Korean Med Sci 2018; 33:e158. [PMID: 29780296 PMCID: PMC5955738 DOI: 10.3346/jkms.2018.33.e158] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 03/26/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The purpose of this study was to qualitatively and quantitatively evaluate the effects of a metal artifact reduction for orthopedic implants (O-MAR) for brain computed tomographic angiography (CTA) in patients with aneurysm clips and coils. METHODS The study included 36 consecutive patients with 47 intracranial metallic implants (42 aneurysm clips, 5 coils) who underwent brain CTA. The computed tomographic images with and without the O-MAR were independently reviewed both quantitatively and qualitatively by two reviewers. For quantitative analysis, image noises near the metallic implants of non-O-MAR and O-MAR images were compared. For qualitative analysis, image quality improvement and the presence of new streak artifacts were assessed. RESULTS Image noise was significantly reduced near metallic implants (P < 0.01). Improvement of implant-induced streak artifacts was observed in eight objects (17.0%). However, streak artifacts were aggravated in 11 objects (23.4%), and adjacent vessel depiction was worsened in eight objects (17.0%). In addition, new O-MAR-related streak artifacts were observed in 32 objects (68.1%). New streak artifacts were more prevalent in cases with overlapping metallic implants on the same axial plane than in those without (P = 0.018). Qualitative assessment revealed that the overall image quality was not significantly improved in O-MAR images. CONCLUSION In conclusion, the use of the O-MAR in patients with metallic implants significantly reduces image noise. However, the degree of the streak artifacts and surrounding vessel depiction were not significantly improved on O-MAR images.
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Affiliation(s)
- Leonard Sunwoo
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sun-Won Park
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea
- Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
| | - Jung Hyo Rhim
- Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
| | - Yeonah Kang
- Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
| | - Young Seob Chung
- Department of Neurosurgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
| | - Young-Je Son
- Department of Neurosurgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
| | - Soo Chin Kim
- Department of Radiology, Seoul National University Hospital, Healthcare System Gangnam Center, Seoul, Korea
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Winklhofer S, Hinzpeter R, Stocker D, Baltsavias G, Michels L, Burkhardt JK, Regli L, Valavanis A, Alkadhi H. Combining monoenergetic extrapolations from dual-energy CT with iterative reconstructions: reduction of coil and clip artifacts from intracranial aneurysm therapy. Neuroradiology 2018; 60:281-291. [DOI: 10.1007/s00234-018-1981-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/10/2018] [Indexed: 10/18/2022]
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Losinski SL, Townsend KL, Kruzic JJ, Robertson BL, Sandwisch JMM, Milovancev M, Nemanic S. Computed tomographic imaging and mechanical analysis of cellophane banding secured with locking polymer clips for portosystemic shunts in canine cadavers. Am J Vet Res 2017; 78:1338-1346. [DOI: 10.2460/ajvr.78.11.1338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Clarençon F, Di Maria F, Gabrieli J, Shotar E, Degos V, Nouet A, Biondi A, Sourour NA. Clinical Impact of Flat Panel Volume CT Angiography in Evaluating the Accurate Intraoperative Deployment of Flow-Diverter Stents. AJNR Am J Neuroradiol 2017; 38:1966-1972. [PMID: 28818824 DOI: 10.3174/ajnr.a5343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 06/09/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The deployment of flow-diverter stents may be difficult to analyse on regular DSA. The purpose of our study was to investigate the clinical impact of stent-dedicated flat panel volume CT angiography to evaluate intraoperatively the satisfactory deployment of flow-diverter stents. MATERIALS AND METHODS From January 2009 to April 2015, 83 consecutive patients (mean age, 51 years; 62 women) were treated in our institution with flow-diverter stents. Eighty-seven aneurysms (82 unruptured, 5 ruptured; 77 anterior, 10 posterior circulation) were treated in these 83 patients (4 patients had 2 aneurysms, both treated by means of flow-diverter stents). One patient was treated for a traumatic carotid cavernous fistula. In 80% of the cases (68/85) a flat panel volume CT angiography was performed in the angiographic suite just after the flow-diverter stent deployment. Stent visualization was assessed by 2 independent reviewers. The clinical impact of stent malapposition was evaluated. RESULTS Flow-diverter stent visualization was satisfactory in 73.5% of the cases. In 2 cases (2.9%) the flat panel volume CT angiography prompted the operator to perform an additional intrastent angioplasty for a condition that was previously underestimated. Four patients (4.7%) experienced acute thromboembolic complications; 3 others had delayed thromboembolic complications. Only 1 of these patients had thromboembolic complications (acute or delayed) related to stent misdeployment, which was easily managed intraoperatively with no clinical consequence. CONCLUSIONS Flat panel volume CT angiography is an interesting tool to depict flow-diverter stent misdeployment and may encourage the operator to perform intrastent angioplasty (2.9% of the cases in our experience) to reduce the risks of thromboembolic complications.
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Affiliation(s)
- F Clarençon
- From the Departments of Interventional Neuroradiology (F.C., J.G., E.S., N.-A.S.) .,Paris VI University (F.C., J.G., E.S., V.D.), Pierre et Marie Curie, Paris. France
| | - F Di Maria
- Department of Interventional Neuroradiology (F.D.M.), Foch Hospital, Suresnes, France
| | - J Gabrieli
- From the Departments of Interventional Neuroradiology (F.C., J.G., E.S., N.-A.S.).,Paris VI University (F.C., J.G., E.S., V.D.), Pierre et Marie Curie, Paris. France
| | - E Shotar
- From the Departments of Interventional Neuroradiology (F.C., J.G., E.S., N.-A.S.).,Paris VI University (F.C., J.G., E.S., V.D.), Pierre et Marie Curie, Paris. France
| | - V Degos
- Anesthesiology (V.D.).,Paris VI University (F.C., J.G., E.S., V.D.), Pierre et Marie Curie, Paris. France
| | - A Nouet
- Neurosurgery (A.N.), Pitié-Salpêtrière Hospital. Paris France
| | - A Biondi
- Department of Neuroradiology and Endovascular Therapy (A.B.), Besançon University Hospital, Besançon, France
| | - N-A Sourour
- From the Departments of Interventional Neuroradiology (F.C., J.G., E.S., N.-A.S.)
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Hamie QM, Kobe AR, Mietzsch L, Manhart M, Puippe GD, Pfammatter T, Guggenberger R. Prototype metal artefact reduction algorithm in flat panel computed tomography - evaluation in patients undergoing transarterial hepatic radioembolisation. Eur Radiol 2017; 28:265-273. [DOI: 10.1007/s00330-017-4946-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/12/2017] [Accepted: 06/13/2017] [Indexed: 12/28/2022]
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Zwarzany Ł, Poncyljusz W, Burke TH. Flat detector CT and its applications in the endovascular treatment of wide-necked intracranial aneurysms-A literature review. Eur J Radiol 2017; 88:26-31. [PMID: 28189205 DOI: 10.1016/j.ejrad.2016.12.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 12/21/2016] [Accepted: 12/24/2016] [Indexed: 10/20/2022]
Abstract
Flat detector CT (FDCT) provides cross sectional imaging within an angiographic suite and is increasingly gaining popularity in various areas of interventional radiology, as an alternative imaging modality. Its relatively high spatial resolution improves visualization of intraluminal devices such as intracranial stents or flow-diverters. Device deployment and positioning, in relation to the parent vessel and surrounding structures, are easily assessible with FDCT. Furthermore, with contrast agent administration, it expands the diagnostic capabilities of this new imaging tool. However, beam-hardening artifacts is a major limitation in some cases. The examination can be performed both during the endovascular procedure and for pre- and post-treatment imaging. Intravenous contrast agent injection reduces the risk of complications, making it possible to perform this examination in the outpatient settings. The aim of this paper is to present an overview of published studies reporting experience with FDCT in the field of endovascular neurosurgery and in particular, FDCT's contribution in treatment of wide-necked intracranial aneurysms. The authors have focused specifically on stent-assisted coiling and flow-diverter implantation, since obtaining proper parent vessel wall apposition of these devices is essential for short- and long-term procedural outcomes.
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Affiliation(s)
- Łukasz Zwarzany
- Department of Radiology and Diagnostic Imaging, M. Curie Hospital, Arkońska 4, 71-455 Szczecin, Poland.
| | - Wojciech Poncyljusz
- Departament of Interventional Radiology, Pomeranian Medical University, Neurointerventional Cath Lab MSW Hospital, Al. Powst. Wielkopolskich 72, 70-111 Szczecin, Poland.
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Metal Artifact Reduction in Computed Tomography After Deep Brain Stimulation Electrode Placement Using Iterative Reconstructions. Invest Radiol 2017; 52:18-22. [PMID: 27309775 DOI: 10.1097/rli.0000000000000296] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Diagnostic accuracy of intraoperative computed tomography (CT) after deep brain stimulation (DBS) electrode placement is limited due to artifacts induced by the metallic hardware, which can potentially mask intracranial postoperative complications. Different metal artifact reduction (MAR) techniques have been introduced to reduce artifacts from metal hardware in CT. The purpose of this study was to assess the impact of a novel iterative MAR technique on image quality and diagnostic performance in the follow-up of patients with DBS electrode implementation surgery. MATERIALS AND METHODS Seventeen patients who had received routine intraoperative CT of the head after implantation of DBS electrodes between March 2015 and June 2015 were retrospectively included. Raw data of all patients were reconstructed with standard weighted filtered back projection (WFBP) and additionally with a novel iterative MAR algorithm. We quantified frequencies of density changes to assess quantitative artifact reduction. For evaluation of qualitative image quality, the visibility of numerous cerebral anatomic landmarks and the detectability of intracranial electrodes were scored according to a 4-point scale. Furthermore, artifact strength overall and adjacent to the electrodes was rated. RESULTS Our results of quantitative artifact reduction showed that images reconstructed with iterative MAR (iMAR) contained significantly lower metal artifacts (overall low frequency values, 1608.6 ± 545.5; range, 375.5-3417.2) compared with the WFBP (overall low frequency values, 4487.3 ± 875.4; range, 2218.3-5783.5) reconstructed images (P < 0.004). Qualitative image analysis showed a significantly improved image quality for iMAR (overall anatomical landmarks, 2.49 ± 0.15; median, 3; range, 0-3; overall electrode characteristics, 2.35 ± 0.16; median, 2; range, 0-3; artifact characteristics, 2.16 ± 0.08; median, 2.5; range, 0-3) compared with WFBP (overall anatomical landmarks, 1.21 ± 0.64; median, 1; range, 0-3; overall electrode characteristics, 0.74 ± 0.37; median, 1; range, 0-2; artifact characteristics, 0.51 ± 0.15; median, 0.5; range, 0-2; P < 0.002). CONCLUSIONS Reconstructions of cranial CT images with the novel iMAR algorithm in patients after DBS implantation allows an efficient reduction of metal artifacts near DBS electrodes compared with WFBP reconstructions. We demonstrated an improvement of quantitative and qualitative image quality of iMAR compared with WFBP in patients with DBS electrodes.
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Efficacy and Clinical Utility of a High-Attenuation Object Artifact Reduction Algorithm in Flat-Detector Image Reconstruction Compared With Standard Image Reconstruction. J Comput Assist Tomogr 2017; 41:572-577. [DOI: 10.1097/rct.0000000000000575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Metal artefact reduction algorithm for correction of bone biopsy needle artefact in paediatric C-arm CT images: a qualitative and quantitative assessment. Clin Radiol 2016; 71:925-31. [DOI: 10.1016/j.crad.2016.04.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/20/2016] [Accepted: 04/26/2016] [Indexed: 11/22/2022]
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Gentric JC, Fahed R, Darsaut TE, Salazkin I, Roy D, Raymond J. Fatal arterial rupture during angioplasty of a flow diverter in a recurrent, previously Y-stented giant MCA bifurcation aneurysm. Interv Neuroradiol 2016; 22:278-86. [PMID: 26893302 PMCID: PMC4984368 DOI: 10.1177/1591019916631147] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/13/2016] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND PURPOSE A patient with a previously Y-stented giant left middle cerebral artery (MCA) bifurcation aneurysm returned with a recurrence. MATERIALS AND METHODS A flow diverter (FD) was deployed through one limb of the high-porosity Y-stenting construction. The proximal FD failed to expand and an attempt at balloon angioplasty led to fatal rupture of the MCA. RESULTS Autopsy demonstrated subarachnoid hemorrhage, vessel rupture and fracture of the proximal high-porosity stent. Microscopic photographs showed that the FD had failed to open because the guiding wire had inadvertently exited and re-entered the proximal segment of the high-porosity stent partially incorporated to the wall of the MCA. Balloon dilatation of the FD which had remained collapsed between the stent and the vessel wall caused fracture of the stent and rupture of the artery. CONCLUSION Angioplasty and flow-diversion of previously Y-stented aneurysms can lead to serious complications.
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Affiliation(s)
- Jean-Christophe Gentric
- Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Department of Radiology, Service of Neuroradiology, Canada
| | - Robert Fahed
- Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Department of Radiology, Service of Neuroradiology, Canada
| | - Tim E Darsaut
- University of Alberta Hospital, Mackenzie Health Sciences Centre, Department of Surgery, Division of Neurosurgery, Canada
| | - Igor Salazkin
- Centre Hospitalier de l'Université de Montréal Research Centre (CRCHUM), Notre-Dame Hospital, Interventional Neuroradiology Research Laboratory, Canada
| | - Daniel Roy
- Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Department of Radiology, Service of Neuroradiology, Canada
| | - Jean Raymond
- Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Department of Radiology, Service of Neuroradiology, Canada
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Chintalapani G, Chinnadurai P, Srinivasan V, Chen SR, Shaltoni H, Morsi H, Mawad ME, Kan P. Evaluation of C-arm CT metal artifact reduction algorithm during intra-aneurysmal coil embolization: Assessment of brain parenchyma, stents and flow-diverters. Eur J Radiol 2016; 85:1312-21. [PMID: 27235879 DOI: 10.1016/j.ejrad.2016.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/31/2016] [Accepted: 04/26/2016] [Indexed: 11/24/2022]
Abstract
PURPOSE Flat panel C-arm CT images acquired in the interventional suite provide valuable information regarding brain parenchyma, vasculature, and device status during the procedure. However, these images often suffer from severe streak artifacts due to the presence of metallic objects such as coils. These artifacts limit the capability to make diagnostic inferences and thus need to be reduced for better image interpretation. The main purpose of this paper is to systematically evaluate the accuracy of one such C-arm CT based metal artifact reduction (MAR) algorithm and to demonstrate its usage in both stent and flow diverter assisted coil embolization procedures. METHODS C-arm CT images routinely acquired in 24 patients during coil embolization procedure (stent-assisted (12) and flow-diverter assisted (12)) were included in this study in a retrospective fashion. These images were reconstructed without and with MAR algorithm on an offline workstation and compared using quantitative image analysis metrics. This analysis was carried out to assess the improvements in both brain parenchyma and device visibility with MAR algorithm. Further, ground truth reference images from phantom experiments and clinical data were used for accurate assessment. RESULTS Quantitative image analysis of brain parenchyma showed uniform distribution of grayscale values and reduced image noise after MAR correction. The line profile plot analysis of device profile in both phantom and clinical data demonstrated improved device visibility with MAR correction. CONCLUSIONS MAR algorithm successfully reduced streak artifacts from coil embolization in all cases, thus allowing more accurate assessment of devices and adjacent brain parenchyma.
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Affiliation(s)
| | - Ponraj Chinnadurai
- Angiography Division, Siemens Medical Solutions USA Inc., Hoffman Estates, IL, USA
| | - Visish Srinivasan
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Stephen R Chen
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Hashem Shaltoni
- Department of Diagnostic and Interventional Imaging, UT Health Science Center, Houston, TX, USA
| | - Hesham Morsi
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Michel E Mawad
- Neurological Institute and Neurology, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Peter Kan
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
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Soize S, Gawlitza M, Raoult H, Pierot L. Imaging Follow-Up of Intracranial Aneurysms Treated by Endovascular Means. Stroke 2016; 47:1407-12. [DOI: 10.1161/strokeaha.115.011414] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 02/23/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Sebastien Soize
- From the Department of Neuroradiology, Hôpital Maison Blanche, Université Reims-Champagne-Ardenne, Reims, France (S.S., L.P.); Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany (M.G.); and Department of Neuroradiology, Hôpital Pontchaillou, University of Rennes, Rennes, France (H.R.)
| | - Matthias Gawlitza
- From the Department of Neuroradiology, Hôpital Maison Blanche, Université Reims-Champagne-Ardenne, Reims, France (S.S., L.P.); Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany (M.G.); and Department of Neuroradiology, Hôpital Pontchaillou, University of Rennes, Rennes, France (H.R.)
| | - Hélène Raoult
- From the Department of Neuroradiology, Hôpital Maison Blanche, Université Reims-Champagne-Ardenne, Reims, France (S.S., L.P.); Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany (M.G.); and Department of Neuroradiology, Hôpital Pontchaillou, University of Rennes, Rennes, France (H.R.)
| | - Laurent Pierot
- From the Department of Neuroradiology, Hôpital Maison Blanche, Université Reims-Champagne-Ardenne, Reims, France (S.S., L.P.); Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany (M.G.); and Department of Neuroradiology, Hôpital Pontchaillou, University of Rennes, Rennes, France (H.R.)
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Mennecke A, Svergun S, Scholz B, Royalty K, Dörfler A, Struffert T. Evaluation of a metal artifact reduction algorithm applied to post-interventional flat detector CT in comparison to pre-treatment CT in patients with acute subarachnoid haemorrhage. Eur Radiol 2016; 27:88-96. [DOI: 10.1007/s00330-016-4351-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/21/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022]
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Yu SCH, Lee KT, Lau TWW, Wong GKC, Pang VKY, Chan KY. Intravenous C-Arm Conebeam CT Angiography following Long-Term Flow-Diverter Implantation: Technologic Evaluation and Preliminary Results. AJNR Am J Neuroradiol 2016; 37:481-6. [PMID: 26585252 DOI: 10.3174/ajnr.a4558] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/29/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE A noninvasive investigation with high spatial resolution and without metal artifacts is necessary for long-term imaging follow-up after flow-diverter implantation. We aimed to evaluate the diagnostic value of conebeam CT angiography with intravenous contrast enhancement in the assessment of vascular status following implantation of the Pipeline Embolization Device and to analyze the preliminary results of vascular status following long-term Pipeline Embolization Device implantation. MATERIALS AND METHODS This was an ongoing prospective study of consecutive patients with intracranial aneurysms treated with the Pipeline Embolization Device. Patients with a modified Rankin Scale score of 4-5 were excluded. The median and interquartile range of the time interval of Pipeline Embolization Device implantation to conebeam CT angiography with intravenous contrast enhancement were 56.6 and 42.9-62.4 months, respectively. Conebeam CT angiography with intravenous contrast enhancement was performed with the patient fully conscious, by using a C-arm CT with a flat panel detector. RESULTS There were 34 patients and 34 vascular segments. In all 34 cases, contrast effect and image quality were good and not substantially different from those of intra-arterial conebeam CTA. Metal artifacts occurred in all 14 cases with coil masses; the Pipeline Embolization Device was obscured in 3 cases. In all 34 cases, there was no residual aneurysm, no vascular occlusion, 1 vascular stenosis (50%), good Pipeline Embolization Device apposition to the vessel, and no Pipeline Embolization Device-induced calcification. All 28 Pipeline Embolization Device-covered side branches were patent. CONCLUSIONS Conebeam CT angiography with intravenous contrast enhancement is potentially promising and useful for effective evaluation of the vascular status following intracranial flow diverters. The Pipeline Embolization Device for intracranial aneurysms is probably safe and promising for long-term placement, with favorable morphologic outcome and without delayed complications.
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Affiliation(s)
- S C H Yu
- From the Department of Imaging and Interventional Radiology (S.C.H.Y., K.T.L., T.W.W.L.)
| | - K T Lee
- From the Department of Imaging and Interventional Radiology (S.C.H.Y., K.T.L., T.W.W.L.)
| | - T W W Lau
- From the Department of Imaging and Interventional Radiology (S.C.H.Y., K.T.L., T.W.W.L.)
| | - G K C Wong
- Division of Neurosurgery (G.K.C.W.), Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR
| | - V K Y Pang
- Department of Neurosurgery (V.K.Y.P.), Pamela Youde Nethersole Eastern Hospital, Hong Kong, SAR
| | - K Y Chan
- Department of Neurosurgery (K.Y.C.), Kwong Wah Hospital, Yaumatei, Kowloon, Hong Kong, SAR
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Duckworth EAM, Nickele C, Schafer S, Bauer S, Scholz B, Elijovich L, Hoit D, Doss VT, Arthur AS. Separating the wheat from the chaff: region of interest combined with metal artifact reduction for completion angiography following cerebral aneurysm treatment. J Neurointerv Surg 2015; 8:1163-1167. [DOI: 10.1136/neurintsurg-2015-011911] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/30/2015] [Indexed: 11/04/2022]
Abstract
IntroductionFollowing complicated endovascular or microsurgical treatments, assessment of radiographic outcome can be challenging due to device resolution and metallic artifact. Two-dimensional and three-dimensional angiography can reveal information about flow and aneurysm obliteration, but may be limited by beam hardening, overlapping vessels, and image degradation in the region of metallic implants. In this study, we investigated the combination of a collimated volumetric imaging (volume of interest, VOI) protocol followed by metal artifact reduction (MAR) post-processing to evaluate the correct positioning of stents, flow diverters, coils, and clips while limiting the radiation dose to the patient.Methods9 patients undergoing 10 procedures were included in our study. All patients underwent endovascular or surgical treatment of a cerebral aneurysm involving stents, flow diverting stents, coils, and/or clips followed by either immediate or early postoperative evaluation of our protocol.ResultsImage datasets corrected for metallic artifacts (VOI-MAR) were judged to be better—a statistically significant finding—than image datasets only corrected for field of view truncation (VOI alone). Qualitatively, images were more interpretable and informative with regards to device position and apposition to the vessel wall for those cases involving a pipeline, and with regards to encroachment on the parent artery and possible residual aneurysm, in all cases.ConclusionsVOI acquisition combined with MAR post-processing provides for accurate and informative evaluation of cerebral aneurysm treatment while limiting the radiation dose to patients.
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Pjontek R, Önenköprülü B, Scholz B, Kyriakou Y, Schubert GA, Nikoubashman O, Othman A, Wiesmann M, Brockmann MA. Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment. J Neurointerv Surg 2015; 8:824-9. [PMID: 26346458 PMCID: PMC4975832 DOI: 10.1136/neurintsurg-2015-011787] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/13/2015] [Indexed: 11/03/2022]
Abstract
BACKGROUND Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. OBJECTIVE To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. METHODS Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. RESULTS MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. CONCLUSIONS When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips.
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Affiliation(s)
- Rastislav Pjontek
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Belgin Önenköprülü
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Bernhard Scholz
- Healthcare, Imaging & Therapy Division, Siemens AG, Forchheim, Germany
| | - Yiannis Kyriakou
- Healthcare, Imaging & Therapy Division, Siemens AG, Forchheim, Germany
| | - Gerrit A Schubert
- Department of Neurosurgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Omid Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany Institute of Neuroscience and Medicine 4, Medical Imaging Physics, Forschungszentrum Jülich, Jülich, Germany
| | - Ahmed Othman
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Marc A Brockmann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany
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Ott S, Gölitz P, Adamek E, Royalty K, Doerfler A, Struffert T. Flat-detector computed tomography evaluation in an experimental animal aneurysm model after endovascular treatment: A pilot study. Interv Neuroradiol 2015; 21:490-8. [PMID: 26111985 DOI: 10.1177/1591019915590364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We compared flat-detector computed tomography angiography (FD-CTA) to multislice computed tomography (MS-CTA) and digital subtracted angiography (DSA) for the visualization of experimental aneurysms treated with stents, coils or a combination of both.In 20 rabbits, aneurysms were created using the rabbit elastase aneurysm model. Seven aneurysms were treated with coils, seven with coils and stents, and six with self-expandable stents alone. Imaging was performed by DSA, MS-CTA and FD-CTA immediately after treatment. Multiplanar reconstruction (MPR) was performed and two experienced reviewers compared aneurysm/coil package size, aneurysm occlusion, stent diameters and artifacts for each modality.In aneurysms treated with stents alone, the visualization of the aneurysms was identical in all three imaging modalities. Residual aneurysm perfusion was present in two cases and visible in DSA and FD-CTA but not in MS-CTA. The diameter of coil-packages was overestimated in MS-CT by 56% and only by 16% in FD-CTA compared to DSA (p < 0.05). The diameter of stents was identical for DSA and FD-CTA and was significantly overestimated in MS-CTA (p < 0.05). Beam/metal hardening artifacts impaired image quality more severely in MS-CTA compared to FD-CTA.MS-CTA is impaired by blooming and beam/metal hardening artifacts in the visualization of implanted devices. There was no significant difference between measurements made with noninvasive FD-CTA compared to gold standard of DSA after stenting and after coiling/stent-assisted coiling of aneurysms. FD-CTA may be considered as a non-invasive alternative to the gold standard 2D DSA in selected patients that require follow up imaging after stenting.
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Affiliation(s)
- Sabine Ott
- Department of Neuroradiology, University of Erlangen-Nuremberg, Germany
| | - Philipp Gölitz
- Department of Neuroradiology, University of Erlangen-Nuremberg, Germany
| | - Edyta Adamek
- Department of Neuroradiology, University of Erlangen-Nuremberg, Germany
| | - Kevin Royalty
- Department of Biomedical Engineering and School of Medicine and Public Health, University of Wisconsin, USA
| | - Arnd Doerfler
- Department of Neuroradiology, University of Erlangen-Nuremberg, Germany
| | - Tobias Struffert
- Department of Neuroradiology, University of Erlangen-Nuremberg, Germany
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Hu J, Shi S, Xie S, Tang X, Chen K, Mu W. Intra-arterial DynaCT angiography: an alternative tool to assess the patency of intracranial stent lumen. Clin Neurol Neurosurg 2015; 130:105-9. [PMID: 25603123 DOI: 10.1016/j.clineuro.2014.08.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/10/2014] [Accepted: 08/23/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The aim of this retrospective study was to assess the clinical utility of intra-arterial DynaCT angiographic imaging for the evaluation of intracranial stent patency. METHODS Between July 2011 and May 2014, 35 patients with symptomatic intracranial atherosclerotic stenosis (ICAS) were treated with percutaneous transluminal angioplasty and stents. All were evaluated with intra-arterial DynaCT angiographic imaging during the operations and follow-up. All images were further processed with three different kernels (sharp, normal, or smooth). RESULTS Thirty-six stents were implanted into the parent arteries. DynaCT provided "good" quality images (median score of 2 or 3 on a 5-point scale) with minimal artifact interference as rated by observers blind to treatment history and other imaging results. The median subjective visibility score was highest (3) using the sharp kernel. CONCLUSIONS DynaCT with sharp kernel image processing achieved good visualization of luminal patency following intracranial stents.
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Affiliation(s)
- Jun Hu
- Department of Neurology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, China
| | - Shugui Shi
- Department of Neurology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, China
| | - Shoujia Xie
- Department of Neurology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, China
| | - Xuesong Tang
- Department of Radiology, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China
| | - Kangning Chen
- Department of Neurology, Southwest Hospital, the Third Military Medical University, Chongqing 400038, China.
| | - Wei Mu
- Department of Radiology, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
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de Oliveira Manoel AL, Mansur A, Murphy A, Turkel-Parrella D, Macdonald M, Macdonald RL, Montanera W, Marotta TR, Bharatha A, Effendi K, Schweizer TA. Aneurysmal subarachnoid haemorrhage from a neuroimaging perspective. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:557. [PMID: 25673429 PMCID: PMC4331293 DOI: 10.1186/s13054-014-0557-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Neuroimaging is a key element in the management of patients suffering from subarachnoid haemorrhage (SAH). In this article, we review the current literature to provide a summary of the existing neuroimaging methods available in clinical practice. Noncontrast computed tomography is highly sensitive in detecting subarachnoid blood, especially within 6 hours of haemorrhage. However, lumbar puncture should follow a negative noncontrast computed tomography scan in patients with symptoms suspicious of SAH. Computed tomography angiography is slowly replacing digital subtraction angiography as the first-line technique for the diagnosis and treatment planning of cerebral aneurysms, but digital subtraction angiography is still required in patients with diffuse SAH and negative initial computed tomography angiography. Delayed cerebral ischaemia is a common and serious complication after SAH. The modern concept of delayed cerebral ischaemia monitoring is shifting from modalities that measure vessel diameter to techniques focusing on brain perfusion. Lastly, evolving modalities applied to assess cerebral physiological, functional and cognitive sequelae after SAH, such as functional magnetic resonance imaging or positron emission tomography, are discussed. These new techniques may have the advantage over structural modalities due to their ability to assess brain physiology and function in real time. However, their use remains mainly experimental and the literature supporting their practice is still scarce.
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Stidd DA, Theessen H, Deng Y, Li Y, Scholz B, Rohkohl C, Jhaveri MD, Moftakhar R, Chen M, Lopes DK. Evaluation of a metal artifacts reduction algorithm applied to postinterventional flat panel detector CT imaging. AJNR Am J Neuroradiol 2014; 35:2164-9. [PMID: 25125663 DOI: 10.3174/ajnr.a4079] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Flat panel detector CT images are degraded by streak artifacts caused by radiodense implanted materials such as coils or clips. A new metal artifacts reduction prototype algorithm has been used to minimize these artifacts. The application of this new metal artifacts reduction algorithm was evaluated for flat panel detector CT imaging performed in a routine clinical setting. MATERIALS AND METHODS Flat panel detector CT images were obtained from 59 patients immediately following cerebral endovascular procedures or as surveillance imaging for cerebral endovascular or surgical procedures previously performed. The images were independently evaluated by 7 physicians for metal artifacts reduction on a 3-point scale at 2 locations: immediately adjacent to the metallic implant and 3 cm away from it. The number of visible vessels before and after metal artifacts reduction correction was also evaluated within a 3-cm radius around the metallic implant. RESULTS The metal artifacts reduction algorithm was applied to the 59 flat panel detector CT datasets without complications. The metal artifacts in the reduction-corrected flat panel detector CT images were significantly reduced in the area immediately adjacent to the implanted metal object (P = .05) and in the area 3 cm away from the metal object (P = .03). The average number of visible vessel segments increased from 4.07 to 5.29 (P = .1235) after application of the metal artifacts reduction algorithm to the flat panel detector CT images. CONCLUSIONS Metal artifacts reduction is an effective method to improve flat panel detector CT images degraded by metal artifacts. Metal artifacts are significantly decreased by the metal artifacts reduction algorithm, and there was a trend toward increased vessel-segment visualization.
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Affiliation(s)
- D A Stidd
- From the Departments of Neurosurgery (D.A.S., R.M., M.C., D.K.L.)
| | - H Theessen
- Siemens Healthcare Sector (B.S., C.R., H.T.), Erlangen, Germany
| | - Y Deng
- Internal Medicine (Y.D., Y.L.)
| | - Y Li
- Internal Medicine (Y.D., Y.L.)
| | - B Scholz
- Siemens Healthcare Sector (B.S., C.R., H.T.), Erlangen, Germany
| | - C Rohkohl
- Siemens Healthcare Sector (B.S., C.R., H.T.), Erlangen, Germany
| | - M D Jhaveri
- Radiology (M.D.J.), Rush University Medical Center, Chicago, Illinois
| | - R Moftakhar
- From the Departments of Neurosurgery (D.A.S., R.M., M.C., D.K.L.)
| | - M Chen
- From the Departments of Neurosurgery (D.A.S., R.M., M.C., D.K.L.)
| | - D K Lopes
- From the Departments of Neurosurgery (D.A.S., R.M., M.C., D.K.L.)
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Müller K, Maier AK, Schwemmer C, Lauritsch G, De Buck S, Wielandts JY, Hornegger J, Fahrig R. Image artefact propagation in motion estimation and reconstruction in interventional cardiac C-arm CT. Phys Med Biol 2014; 59:3121-38. [PMID: 24840084 DOI: 10.1088/0031-9155/59/12/3121] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The acquisition of data for cardiac imaging using a C-arm computed tomography system requires several seconds and multiple heartbeats. Hence, incorporation of motion correction in the reconstruction step may improve the resulting image quality. Cardiac motion can be estimated by deformable three-dimensional (3D)/3D registration performed on initial 3D images of different heart phases. This motion information can be used for a motion-compensated reconstruction allowing the use of all acquired data for image reconstruction. However, the result of the registration procedure and hence the estimated deformations are influenced by the quality of the initial 3D images. In this paper, the sensitivity of the 3D/3D registration step to the image quality of the initial images is studied. Different reconstruction algorithms are evaluated for a recently proposed cardiac C-arm CT acquisition protocol. The initial 3D images are all based on retrospective electrocardiogram (ECG)-gated data. ECG-gating of data from a single C-arm rotation provides only a few projections per heart phase for image reconstruction. This view sparsity leads to prominent streak artefacts and a poor signal to noise ratio. Five different initial image reconstructions are evaluated: (1) cone beam filtered-backprojection (FDK), (2) cone beam filtered-backprojection and an additional bilateral filter (FFDK), (3) removal of the shadow of dense objects (catheter, pacing electrode, etc) before reconstruction with a cone beam filtered-backprojection (cathFDK), (4) removal of the shadow of dense objects before reconstruction with a cone beam filtered-backprojection and a bilateral filter (cathFFDK). The last method (5) is an iterative few-view reconstruction (FV), the prior image constrained compressed sensing combined with the improved total variation algorithm. All reconstructions are investigated with respect to the final motion-compensated reconstruction quality. The algorithms were tested on a mathematical phantom data set with and without a catheter and on two porcine models using qualitative and quantitative measures. The quantitative results of the phantom experiments show that if no dense object is present within the scan field of view, the quality of the FDK initial images is sufficient for motion estimation via 3D/3D registration. When a catheter or pacing electrode is present, the shadow of these objects needs to be removed before the initial image reconstruction. An additional bilateral filter shows no major improvement with respect to the final motion-compensated reconstruction quality. The results with respect to image quality of the cathFDK, cathFFDK and FV images are comparable. In conclusion, in terms of computational complexity, the algorithm of choice is the cathFDK algorithm.
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Affiliation(s)
- K Müller
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr 3, D-91058 Erlangen, Germany. Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordan-Str 6, D-91052 Erlangen, Germany
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Flood TF, van der Bom IMJ, Strittmatter L, Puri AS, Hendricks GM, Wakhloo AK, Gounis MJ. Quantitative analysis of high-resolution, contrast-enhanced, cone-beam CT for the detection of intracranial in-stent hyperplasia. J Neurointerv Surg 2014; 7:118-25. [PMID: 24480728 PMCID: PMC4316917 DOI: 10.1136/neurintsurg-2013-010950] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Intracranial in-stent hyperplasia is a stroke-associated complication that requires routine surveillance. OBJECTIVE To compare the results of in vivo experiments to determine the accuracy and precision of in-stent hyperplasia measurements obtained with modified C-arm contrast-enhanced, cone-beam CT (CE-CBCT) imaging with those obtained by 'gold standard' histomorphometry. Additionally, to carry out clinical analyses comparing this CE-CBCT protocol with digital subtraction angiography (DSA). METHODS A non-binned CE-CBCT protocol (VasoCT) was used that acquires x-ray images with a small field-of-view and applies a full-scale reconstruction algorithm providing high-resolution three-dimensional (3D) imaging with 100 µm isotropic voxels. In an vivo porcine model, VasoCT cross-sectional area measurements were compared with gold standard vessel histology. VasoCT and DSA were used to calculate in-stent stenosis in 23 imaging studies. RESULTS Porcine VasoCT cross-sectional stent, lumen, and in-stent hyperplasia areas strongly correlated with histological measurements (r(2)=0.97, 0.93, 0.90; slope=1.14, 1.07, and 0.76, respectively; p<0.0001). Clinical VasoCT percentage stenosis correlated well with DSA percentage stenosis (r(2)=0.84; slope=0.76), and the two techniques were free of consistent bias (Bland-Altman, bias=3.29%; 95% CI -14.75% to 21.33%). An illustrative clinical case demonstrated the advantages of VasoCT, including 3D capability and non-invasive IV contrast administration, for detection of in-stent hyperplasia. CONCLUSIONS C-arm VasoCT is a high-resolution 3D capable imaging technique that has been validated in an animal model for measurement of in-stent tissue growth. Successful clinical implementation of the protocol was performed in a small case series.
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Affiliation(s)
- Thomas F Flood
- Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Imramsjah M J van der Bom
- Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Lara Strittmatter
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ajit S Puri
- Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Gregory M Hendricks
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ajay K Wakhloo
- Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Matthew J Gounis
- Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Hung SC, Wu CC, Lin CJ, Guo WY, Luo CB, Chang FC, Chang CY. Artifact reduction of different metallic implants in flat detector C-arm CT. AJNR Am J Neuroradiol 2014; 35:1288-92. [PMID: 24457821 DOI: 10.3174/ajnr.a3851] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Flat detector CT has been increasingly used as a follow-up examination after endovascular intervention. Metal artifact reduction has been successfully demonstrated in coil mass cases, but only in a small series. We attempted to objectively and subjectively evaluate the feasibility of metal artifact reduction with various metallic objects and coil lengths. MATERIALS AND METHODS We retrospectively reprocessed the flat detector CT data of 28 patients (15 men, 13 women; mean age, 55.6 years) after they underwent endovascular treatment (20 coiling ± stent placement, 6 liquid embolizers) or shunt drainage (n = 2) between January 2009 and November 2011 by using a metal artifact reduction correction algorithm. We measured CT value ranges and noise by using region-of-interest methods, and 2 experienced neuroradiologists rated the degrees of improved imaging quality and artifact reduction by comparing uncorrected and corrected images. RESULTS After we applied the metal artifact reduction algorithm, the CT value ranges and the noise were substantially reduced (1815.3 ± 793.7 versus 231.7 ± 95.9 and 319.9 ± 136.6 versus 45.9 ± 14.0; both P < .001) regardless of the types of metallic objects and various sizes of coil masses. The rater study achieved an overall improvement of imaging quality and artifact reduction (85.7% and 78.6% of cases by 2 raters, respectively), with the greatest improvement in the coiling group, moderate improvement in the liquid embolizers, and the smallest improvement in ventricular shunting (overall agreement, 0.857). CONCLUSIONS The metal artifact reduction algorithm substantially reduced artifacts and improved the objective image quality in every studied case. It also allowed improved diagnostic confidence in most cases.
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Affiliation(s)
- S-C Hung
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanDepartment of Biomedical Imaging and Radiological Sciences (S.-C.H.)School of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan
| | - C-C Wu
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan
| | - C-J Lin
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan
| | - W-Y Guo
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan.
| | - C-B Luo
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan
| | - F-C Chang
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan
| | - C-Y Chang
- From the Department of Radiology (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), Taipei Veterans General Hospital, Taipei, TaiwanSchool of Medicine (S.-C.H., C.-C.W., C.-J.L., W.-Y.G., C.-B.L., F.-C.C., C.-Y.C.), National Yang-Ming University, Taipei, Taiwan
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