International Journal of Nanomedicine (Jan 2021)
Magnetic Particle Imaging: In vitro Signal Analysis and Lumen Quantification of 21 Endovascular Stents
Abstract
Franz Wegner,1,* Anselm von Gladiss,2,* Julian Haegele,1,3 Ulrike Grzyska,1 Malte Maria Sieren,1 Erik Stahlberg,1 Thekla Helene Oechtering,1 Kerstin Lüdtke-Buzug,2 Joerg Barkhausen,1 Thorsten M Buzug,2,4 Thomas Friedrich2,4 1Department of Radiology and Nuclear Medicine, University of Lübeck, Lübeck, Germany; 2Institute of Medical Engineering, University of Lübeck, Lübeck, Germany; 3Zentrum für Radiologie und Nuklearmedizin Rheinland, Dormagen, Germany; 4Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering, Lübeck, Germany*These authors contributed equally to this workCorrespondence: Franz WegnerUniversity Hospital Schleswig-Holstein, Campus Lübeck, Department of Radiology and Nuclear Medicine, Ratzeburger Allee 160, Lübeck 23538, GermanyTel +004945150017001Fax +004945150017004Email [email protected]: Endovascular stents are medical devices, which are implanted in stenosed blood vessels to ensure sufficient blood flow. Due to a high rate of in-stent re-stenoses, there is the need of a noninvasive imaging method for the early detection of stent occlusion. The evaluation of the stent lumen with computed tomography (CT) and magnetic resonance imaging (MRI) is limited by material-induced artifacts. The purpose of this work is to investigate the potential of the tracer-based modality magnetic particle imaging (MPI) for stent lumen visualization and quantification.Methods: In this in vitro study, 21 endovascular stents were investigated in a preclinical MPI scanner. Therefore, the stents were implanted in vessel phantoms. For the signal analysis, the phantoms were scanned without tracer material, and the signal-to-noise-ratio was analyzed. For the evaluation of potential artifacts and the lumen quantification, the phantoms were filled with diluted tracer agent. To calculate the stent lumen diameter a calibrated threshold value was applied.Results: We can show that it is possible to visualize the lumen of a variety of endovascular stents without material induced artifacts, as the stents do not generate sufficient signals in MPI. The stent lumen quantification showed a direct correlation between the calculated and nominal diameter (r = 0.98).Conclusion: In contrast to MRI and CT, MPI is able to visualize and quantify stent lumina very accurately.Keywords: magnetic particle imaging, endovascular stents, artifacts, superparamagnetic iron oxide nanoparticles, lumen quantification
