{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:61248"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:61248","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Quantitative Signal- und Artefaktuntersuchungen zur Kategorisierung von Gefäßendoprothesen in vitro : Möglichkeiten der kontrastverstärkten 3D-Magnetresonanz-Angiographie im Vergleich zur Computertomographie","abstract":"For treatment of abdominal aortic aneurysms transfemoral, endovascular stented graft repair can satisfactorily be performed. Postinterventional, typical complications as endoleaks, thrombosis and structural failure are described, which make long-term follow-up imaging necessary. Computed tomography (CT) has been recommended as a primary imaging technique. However, metallic implants such as stents often cause severe artifacts (such as beam-hardening and partial volume artifacts), which can limit the assessment of both the lumen and the surrounding tissue. Additionally the required radiation dose should be considered. Three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) has become competitive as a diagnostic modality. The MR compatibility of stents regarding security and visualization has already been confirmed both in vitro and in vivo. However, typical susceptibility and nonsusceptibility artifacts like eddy currents or radio-frequency shielding are known to drastically reduce MR image quality. The aim of this study is to evaluate the imaging appearance of routinely used bifurcated and tubular endoprostheses in contrast-enhanced 3D-MRA. Firstly, the influence of different sequence parameters on the representation is evaluated, in order to specify the optimal sequence for further investigations. Secondly, quantitative signal and artifact investigations allow the identification of stent characteristics in order to establish a ranking of visualization. Thirdly, these images are evaluated in comparison with the appearance of the endoprotheses in computed tomography. Finally, diagnostic recommendations are drafted for each endoprosthesis. The variation of sequence parameters shows that the echo time (TE) affects the visualization most strongly; a short echo time reduces susceptibility artifacts of gradient echo sequences. The flip angle (FA) affects the RF caging inside the stents. A flip angle of 40° provides good visualization, the application of higher flip angles may even improve in-stent visualization.A smaller field-of-view (FOV) leads to a better representation of the prosthesis lumen by reducing the signal-to-noise-ratio (SNR). A change of the water fat shift (WFS) does not affect the lumen visualization. Parameters of the optimized sequence are TR 8.1 ms, TE 1.3 ms, FA 40°, FOV 300 mm³, WFS 0.700. Both geometry of the stents and underlying material composition are associated with MR imaging artifacts. Due to the different susceptibility bifurcated protheses made from Nitinol show a better in-stent lumen visualization than stents from cobalt alloys; the stainless steel prosthesis is not MR compatible. A close meshed geometry relates to worse lumen visualization, probably because of radio frequency shielding. In CT, the influence of beamlike artifacts on the lumen visualization is evident. These mainly derive from platinum and gold markers. Finally, diagnostic recommendations are drafted for each endoprosthesis: MRA should be preferred for the bifurcated stentgrafts by Talent and Vanguard. The Gore prostheses and the Talent tubular prosthesis are suitable both for CT and MRA. CT is the prime imaging modality for AneuRx , Lifepath and Bard bifurcated stentgrafts and the only suitable imaging modality for the prostheses by Corvita and Zenith. For the Ancure prostheses the combination of both imaging modalities is recommended.","abstract_html":"For treatment of abdominal aortic aneurysms transfemoral, endovascular stented graft repair can satisfactorily be performed. Postinterventional, typical complications as endoleaks, thrombosis and structural failure are described, which make long-term follow-up imaging necessary. Computed tomography (CT) has been recommended as a primary imaging technique. However, metallic implants such as stents often cause severe artifacts (such as beam-hardening and partial volume artifacts), which can limit the assessment of both the lumen and the surrounding tissue. Additionally the required radiation dose should be considered. Three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) has become competitive as a diagnostic modality. The MR compatibility of stents regarding security and visualization has already been confirmed both in vitro and in vivo. However, typical susceptibility and nonsusceptibility artifacts like eddy currents or radio-frequency shielding are known to drastically reduce MR image quality. The aim of this study is to evaluate the imaging appearance of routinely used bifurcated and tubular endoprostheses in contrast-enhanced 3D-MRA. Firstly, the influence of different sequence parameters on the representation is evaluated, in order to specify the optimal sequence for further investigations. Secondly, quantitative signal and artifact investigations allow the identification of stent characteristics in order to establish a ranking of visualization. Thirdly, these images are evaluated in comparison with the appearance of the endoprotheses in computed tomography. Finally, diagnostic recommendations are drafted for each endoprosthesis. The variation of sequence parameters shows that the echo time (TE) affects the visualization most strongly; a short echo time reduces susceptibility artifacts of gradient echo sequences. The flip angle (FA) affects the RF caging inside the stents. A flip angle of 40° provides good visualization, the application of higher flip angles may even improve in-stent visualization.A smaller field-of-view (FOV) leads to a better representation of the prosthesis lumen by reducing the signal-to-noise-ratio (SNR). A change of the water fat shift (WFS) does not affect the lumen visualization. Parameters of the optimized sequence are TR 8.1 ms, TE 1.3 ms, FA 40°, FOV 300 mm³, WFS 0.700. Both geometry of the stents and underlying material composition are associated with MR imaging artifacts. Due to the different susceptibility bifurcated protheses made from Nitinol show a better in-stent lumen visualization than stents from cobalt alloys; the stainless steel prosthesis is not MR compatible. A close meshed geometry relates to worse lumen visualization, probably because of radio frequency shielding. In CT, the influence of beamlike artifacts on the lumen visualization is evident. These mainly derive from platinum and gold markers. Finally, diagnostic recommendations are drafted for each endoprosthesis: MRA should be preferred for the bifurcated stentgrafts by Talent and Vanguard. The Gore prostheses and the Talent tubular prosthesis are suitable both for CT and MRA. CT is the prime imaging modality for AneuRx , Lifepath and Bard bifurcated stentgrafts and the only suitable imaging modality for the prostheses by Corvita and Zenith. For the Ancure prostheses the combination of both imaging modalities is recommended.","abstract_has_math":false,"creators":["Hütten, Matthias Christian"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Bücker, Arno"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2006,"date_issued":"2006","date_published":"2006","updated_at":"2026-07-30T19:43:10Z","subjects":["info:eu-repo/classification/ddc/610","Medizin","Magnetresonanzangiographie","Bauchaorta","Aneurysma","Stent","Artefakt","Computertomographie","Bifurkationsprothesen","Stents","magnetic resonance angiography","artifacts"],"languages":["ger"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122926%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122926%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122926%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/61248","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bücker, Arno"]},{"key":"dc:creator","label":"Author","values":["Hütten, Matthias Christian"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2006"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-15321"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/610","Medizin","Magnetresonanzangiographie","Bauchaorta","Aneurysma","Stent","Artefakt","Computertomographie","Bifurkationsprothesen","Stents","magnetic resonance angiography","artifacts"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["ger"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/61248","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122926%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["For treatment of abdominal aortic aneurysms transfemoral, endovascular stented graft repair can satisfactorily be performed. Postinterventional, typical complications as endoleaks, thrombosis and structural failure are described, which make long-term follow-up imaging necessary. Computed tomography (CT) has been recommended as a primary imaging technique. However, metallic implants such as stents often cause severe artifacts (such as beam-hardening and partial volume artifacts), which can limit the assessment of both the lumen and the surrounding tissue. Additionally the required radiation dose should be considered. Three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) has become competitive as a diagnostic modality. The MR compatibility of stents regarding security and visualization has already been confirmed both in vitro and in vivo. However, typical susceptibility and nonsusceptibility artifacts like eddy currents or radio-frequency shielding are known to drastically reduce MR image quality. The aim of this study is to evaluate the imaging appearance of routinely used bifurcated and tubular endoprostheses in contrast-enhanced 3D-MRA. Firstly, the influence of different sequence parameters on the representation is evaluated, in order to specify the optimal sequence for further investigations. Secondly, quantitative signal and artifact investigations allow the identification of stent characteristics in order to establish a ranking of visualization. Thirdly, these images are evaluated in comparison with the appearance of the endoprotheses in computed tomography. Finally, diagnostic recommendations are drafted for each endoprosthesis. The variation of sequence parameters shows that the echo time (TE) affects the visualization most strongly; a short echo time reduces susceptibility artifacts of gradient echo sequences. The flip angle (FA) affects the RF caging inside the stents. A flip angle of 40° provides good visualization, the application of higher flip angles may even improve in-stent visualization.A smaller field-of-view (FOV) leads to a better representation of the prosthesis lumen by reducing the signal-to-noise-ratio (SNR). A change of the water fat shift (WFS) does not affect the lumen visualization. Parameters of the optimized sequence are TR 8.1 ms, TE 1.3 ms, FA 40°, FOV 300 mm³, WFS 0.700. Both geometry of the stents and underlying material composition are associated with MR imaging artifacts. Due to the different susceptibility bifurcated protheses made from Nitinol show a better in-stent lumen visualization than stents from cobalt alloys; the stainless steel prosthesis is not MR compatible. A close meshed geometry relates to worse lumen visualization, probably because of radio frequency shielding. In CT, the influence of beamlike artifacts on the lumen visualization is evident. These mainly derive from platinum and gold markers. Finally, diagnostic recommendations are drafted for each endoprosthesis: MRA should be preferred for the bifurcated stentgrafts by Talent and Vanguard. The Gore prostheses and the Talent tubular prosthesis are suitable both for CT and MRA. CT is the prime imaging modality for AneuRx , Lifepath and Bard bifurcated stentgrafts and the only suitable imaging modality for the prostheses by Corvita and Zenith. For the Ancure prostheses the combination of both imaging modalities is recommended."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University II, 87 S. : Ill., graph. Darst. (2006). = Aachen, Techn. Hochsch., Diss., 2006"]},{"key":"dc:title","label":"Title","values":["Quantitative Signal- und Artefaktuntersuchungen zur Kategorisierung von Gefäßendoprothesen in vitro : Möglichkeiten der kontrastverstärkten 3D-Magnetresonanz-Angiographie im Vergleich zur Computertomographie"]}]}],"canonical_facts":{"dc:contributor":["Bücker, Arno"],"dc:coverage":["DE"],"dc:creator":["Hütten, Matthias Christian"],"dc:date":["2006"],"dc:description":["For treatment of abdominal aortic aneurysms transfemoral, endovascular stented graft repair can satisfactorily be performed. Postinterventional, typical complications as endoleaks, thrombosis and structural failure are described, which make long-term follow-up imaging necessary. Computed tomography (CT) has been recommended as a primary imaging technique. However, metallic implants such as stents often cause severe artifacts (such as beam-hardening and partial volume artifacts), which can limit the assessment of both the lumen and the surrounding tissue. Additionally the required radiation dose should be considered. Three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) has become competitive as a diagnostic modality. The MR compatibility of stents regarding security and visualization has already been confirmed both in vitro and in vivo. However, typical susceptibility and nonsusceptibility artifacts like eddy currents or radio-frequency shielding are known to drastically reduce MR image quality. The aim of this study is to evaluate the imaging appearance of routinely used bifurcated and tubular endoprostheses in contrast-enhanced 3D-MRA. Firstly, the influence of different sequence parameters on the representation is evaluated, in order to specify the optimal sequence for further investigations. Secondly, quantitative signal and artifact investigations allow the identification of stent characteristics in order to establish a ranking of visualization. Thirdly, these images are evaluated in comparison with the appearance of the endoprotheses in computed tomography. Finally, diagnostic recommendations are drafted for each endoprosthesis. The variation of sequence parameters shows that the echo time (TE) affects the visualization most strongly; a short echo time reduces susceptibility artifacts of gradient echo sequences. The flip angle (FA) affects the RF caging inside the stents. A flip angle of 40° provides good visualization, the application of higher flip angles may even improve in-stent visualization.A smaller field-of-view (FOV) leads to a better representation of the prosthesis lumen by reducing the signal-to-noise-ratio (SNR). A change of the water fat shift (WFS) does not affect the lumen visualization. Parameters of the optimized sequence are TR 8.1 ms, TE 1.3 ms, FA 40°, FOV 300 mm³, WFS 0.700. Both geometry of the stents and underlying material composition are associated with MR imaging artifacts. Due to the different susceptibility bifurcated protheses made from Nitinol show a better in-stent lumen visualization than stents from cobalt alloys; the stainless steel prosthesis is not MR compatible. A close meshed geometry relates to worse lumen visualization, probably because of radio frequency shielding. In CT, the influence of beamlike artifacts on the lumen visualization is evident. These mainly derive from platinum and gold markers. Finally, diagnostic recommendations are drafted for each endoprosthesis: MRA should be preferred for the bifurcated stentgrafts by Talent and Vanguard. The Gore prostheses and the Talent tubular prosthesis are suitable both for CT and MRA. CT is the prime imaging modality for AneuRx , Lifepath and Bard bifurcated stentgrafts and the only suitable imaging modality for the prostheses by Corvita and Zenith. For the Ancure prostheses the combination of both imaging modalities is recommended."],"dc:identifier":["https://publications.rwth-aachen.de/record/61248","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122926%22"],"dc:language":["ger"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-15321"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University II, 87 S. : Ill., graph. Darst. (2006). = Aachen, Techn. Hochsch., Diss., 2006"],"dc:subject":["info:eu-repo/classification/ddc/610","Medizin","Magnetresonanzangiographie","Bauchaorta","Aneurysma","Stent","Artefakt","Computertomographie","Bifurkationsprothesen","Stents","magnetic resonance angiography","artifacts"],"dc:title":["Quantitative Signal- und Artefaktuntersuchungen zur Kategorisierung von Gefäßendoprothesen in vitro : Möglichkeiten der kontrastverstärkten 3D-Magnetresonanz-Angiographie im Vergleich zur Computertomographie"],"dc:type":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]},"updated_at":"2026-07-30T19:43:10Z"}