PURPOSE: To evaluate MR artifacts of carotid artery stents and to optimize stent properties and sequence parameters. MATERIAL AND METHODS: Four carotid artery stents - Wallstent (mediloy), Precise (nitinol), ACCULINK (nitinol) and a stent prototype (nitinol) - were investigated in a flow model of the cervical vessels. The model was made of silicon tubing and a flow pump that produces realistic flow curves of the carotid artery. To investigate the effects of magnetic susceptibility and radiofrequency induced shielding artifacts, turbo spin echo and gradient echo sequences as well as CE-MRAs were measured. To improve the visualization of the stent lumen in a CE-MRA, flip angle as well as geometry and covering of the stent prototype were altered. RESULTS: Susceptibility artifacts in stents of the carotid artery only influence the lumen visualization at the proximal and distal end of the braided mediloy stent. A change of stent coverings has no significant influence on radiofrequency artifacts, whereas a reduction in linking elements between stent segments and a change in diameter of stent struts improves visualization of the stent lumen. By increasing the flip angle in a CE-MRA, visualization of the stent lumen is possible in both mediloy and nitinol stents. CONCLUSION: The choice of stent material and changes in stent geometry as well as the optimization of the flip angle of the CE-MRA may reduce susceptibility and radiofrequency artifacts, rendering feasible the CE-MRA of a stented carotid artery.
PURPOSE: To evaluate MR artifacts of carotid artery stents and to optimize stent properties and sequence parameters. MATERIAL AND METHODS: Four carotid artery stents - Wallstent (mediloy), Precise (nitinol), ACCULINK (nitinol) and a stent prototype (nitinol) - were investigated in a flow model of the cervical vessels. The model was made of silicon tubing and a flow pump that produces realistic flow curves of the carotid artery. To investigate the effects of magnetic susceptibility and radiofrequency induced shielding artifacts, turbo spin echo and gradient echo sequences as well as CE-MRAs were measured. To improve the visualization of the stent lumen in a CE-MRA, flip angle as well as geometry and covering of the stent prototype were altered. RESULTS: Susceptibility artifacts in stents of the carotid artery only influence the lumen visualization at the proximal and distal end of the braided mediloy stent. A change of stent coverings has no significant influence on radiofrequency artifacts, whereas a reduction in linking elements between stent segments and a change in diameter of stent struts improves visualization of the stent lumen. By increasing the flip angle in a CE-MRA, visualization of the stent lumen is possible in both mediloy and nitinol stents. CONCLUSION: The choice of stent material and changes in stent geometry as well as the optimization of the flip angle of the CE-MRA may reduce susceptibility and radiofrequency artifacts, rendering feasible the CE-MRA of a stented carotid artery.
Authors: Andreas M J Frölich; Sara M Pilgram-Pastor; Marios N Psychogios; Alexander Mohr; Michael Knauth Journal: Neuroradiology Date: 2010-08-19 Impact factor: 2.804
Authors: Gitsios Gitsioudis; Philipp Fortner; Matthias Stuber; Anna Missiou; Florian Andre; Oliver J Müller; Hugo A Katus; Grigorios Korosoglou Journal: Int J Cardiovasc Imaging Date: 2016-08-17 Impact factor: 2.357
Authors: R Syha; D Ketelsen; M Kaempf; S Mangold; S Sixt; T Zeller; F Springer; F Schick; C D Claussen; K Brechtel Journal: Eur Radiol Date: 2012-08-17 Impact factor: 5.315
Authors: Michael Lettau; Annett Sauer; Sabine Heiland; Stefan Rohde; Julia Reinhardt; Martin Bendszus; Stefan Hähnel Journal: Neuroradiology Date: 2009-11-19 Impact factor: 2.804