Heating of an Aortic Stent for Coarctation Treatment During Magnetic Particle Imaging and Magnetic Resonance Imaging\u2014A Comparative In Vitro Study

Ulrike Grzyska,Thomas Friedrich,Malte M Sieren,Mandy Ahlborg,Thorsten M Buzug,Franz Wegner,Julian Haegele,Thekla H Oechtering,Erik Stahlberg,Alex Frydrychowicz,Joerg Barkhausen

doi:10.1007/s00270-021-02795-4

Abstract

PurposeTo evaluate heating of a redilatable stent for the treatment of aortic coarctation in neonates and small children in the new imaging modality magnetic particle imaging and established magnetic resonance imaging.Materials and MethodsThe cobalt-chromium stent (BabyStent, OSYPKA AG, Rheinfelden, Germany) has a stent design which allows for redilatation and adjustment of the diameter from 6 to 16 mm for a use in aortic coarctation. The stent loses its radial integrity while opening at predetermined breaking points at a diameter of 14 mm or 16 mm, respectively. We measured the temperature increase in the stent at different diameters during 7-min magnetic particle imaging and magnetic resonance imaging scans with fiber optic thermometers under static conditions surrounded by air. In magnetic particle imaging, stents with diameters from 6 to 16 mm were tested while in magnetic resonance imaging only stents with diameters of 6 mm and 14 mm were investigated exemplarily.ResultIn magnetic particle imaging, the measured temperature differences increased up to 4.7 K with growing diameters, whereas the opened stents with discontinuous struts at 14 and 16 mm showed only minimal heating of max. 0.5 K. In contrast to magnetic particle imaging, our measurements showed no heating of the stents during magnetic resonance imaging under identical conditions.ConclusionThe BabyStent did show only slight heating in magnetic particle imaging and no detectable temperature increase in magnetic resonance imaging.

Highlights

Aortic coarctation affects 5–8% of patients suffering from congenital heart disease
Materials and Methods The cobalt-chromium stent (BabyStent, OSYPKA AG, Rheinfelden, Germany) has a stent design which allows for redilatation and adjustment of the diameter from 6 to 16 mm for a use in aortic coarctation
The measurements of this work were performed with balloon-expandable cobalt-chromium stents (BabyStent, OSYPKA AG, Rheinfelden, Germany), which allow for redilatation and adjustment of the diameter from 6 to 16 mm

Summary

Introduction

Aortic coarctation affects 5–8% of patients suffering from congenital heart disease. Surgical treatment was the only therapy [1]. There are various disadvantages of surgical treatment including immediate postoperative complications, e.g. paradoxical hypertension, injury of the recurrent laryngeal nerve or bleeding [2]. Recoarctation is the most frequent long-term complication and requires further operations [1]. In 2011, Forbes et al reported that patients treated with endovascular stenting revealed fewer acute complications compared to surgical therapy [3]. In 2003, a stent design that allows for continuous dilatation after implantation and can be adapted to the growing vessel diameter was introduced [5]. In 2016, the principle of a breaking stent design was applied for the endovascular

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Discussion

Conclusion