Xact stent4/25/2023 ![]() They caused circular signal voids in MRI and areas of high signal intensity in MPI. The bimodal markers were clearly visible in both methods. MPI image reconstruction was performed based on system matrices measured with dried KLB and Bayoxide E8706 coatings. Imaging experiments were conducted using a commercial, preclinical MPI scanner and a preclinical 1 tesla MRI system. Coatings based on both particle types were then applied on a segment of a nonmetallic guidewire. Coatings containing one of both particle types were fabricated and measured with a magnetic particle spectrometer (MPS) to estimate their MPI performance. The instrument markers were based on two different magnetic nanoparticle types (synthesized in-house KLB and commercial Bayoxide E8706). The purpose of this work was to develop instrument markers that are visible in both magnetic particle imaging (MPI) and magnetic resonance imaging (MRI). Thus, we demonstrated that the ability of 3D-TOF-MRA post-CAS was improved via optimizing imaging parameters. Both Carotid Wallstent and PRECISE made imaging capability improved by optimizing the imaging parameters.ĭuring clinical imaging of patients post-carotid artery stenting (CAS) using our protocol, the ability to visualize blood vessels was improved. The influence of RF-shielding effect was large at PRECISE, where the Ernst angle was greatly shifted while the effect is no longer influenced at Carotid Wallstent. The influence of the magnetic susceptibility effect is small in the central part of Carotid Wallstent and in PRECISE, and large in the Carotid Wallstent at the both ends. Optimized 3D time-of-flight MR angiography (3D-TOF-MRA) was performed and compared with conventional 3D-TOF-MRA and computed tomography angiography (CTA). The conventional imaging parameters and the optimum imaging parameters for each stent obtained from the result of the phantom experiment were examined. Similarly, flip angles were changed for two different kinds of stents respectively to the signal intensity between the inside and the outside of the stent was measured, in which examine the relationship between the stent type and the Ernst angles in RF-shielding effect. We investigated the relationship between the stent type and magnetic susceptibility effect by measuring the signal value between the inside and outside of the stent with different Bw and TE for two different kinds of stents respectively. In this study, we investigated the factors of signal loss out because of the presence of a stent and optimized imaging parameters for improvement in depiction ability. Development of stent-specific pathways for follow-up imaging seems advisable to address stent-related differences in image quality. For specific stents, 3D-TOF provided image quality comparable to CE-MRA and may thus be suitable for in vivo assessment. CE-MRA provided better results for the Wallstent, while the Xact stent was difficult to visualize with both MRA protocols.īoth CE-MRA and 3D-TOF are viable options for depicting the in-stent lumen in carotid stents. ALN and RIS were relatively favorable for Acculink®, Precise®, and Zilver® stents with both CE-MRA and 3D-TOF. RIS and ALN depended heavily on stent type, stent diameter, and the employed MR sequence. Stent-related artifacts were objectively assessed by calculating artificial lumen narrowing (ALN) and relative in-stent signal (RIS). In this study, we compared CE-MRA and 3D-TOF of five different carotid stents (Guidant Acculink®, Cordis Precise®, Boston Wallstent®, Abbot Vascular Xact®, Cook Zilver®) in three diameters (4, 6, and 8 mm) using a vascular flow model at 3.0 T with the help of a recently developed carotid surface coil. The aim of this study was to assess contrast-enhanced MRA (CE-MRA) and three-dimensional time-of-flight MRA (3D-TOF) for visualization of the in-stent lumen in different carotid stents. Options include digital subtraction angiography, CT angiography, ultrasound, and MR angiography (MRA), which may offer a non-invasive option for CAS follow-up imaging. Carotid artery stenting (CAS) requires adequate follow-up imaging to assess complications such as in-stent stenosis or occlusion.
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