Segmented nitinol guidewires with stiffness-matched connectors for cardiovascular magnetic resonance catheterization: preserved mechanical performance and freedom from heating

Journal of Cardiovascular Magnetic Resonance

Research

Ozgur Kocaturk¹  Jonathan R. Mazal²  Toby Rogers²  Anthony Z. Faranesh²  Robert J. Lederman²  Merdim Sonmez²  Adrienne E. Campbell-Washburn²  William H. Schenke²  Kanishka Ratnayaka³  Burcu Basar⁴ 

[1] Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey;National Heart Lung and Blood Institute, National Institutes of Health, Building 10, Room 2c713, 20892-1538, Bethesda, MD, USA;National Heart Lung and Blood Institute, National Institutes of Health, Building 10, Room 2c713, 20892-1538, Bethesda, MD, USA;Department of Cardiology, Children’s National Medical Center, Washington DC, USA;National Heart Lung and Blood Institute, National Institutes of Health, Building 10, Room 2c713, 20892-1538, Bethesda, MD, USA;Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey;

关键词: Interventional cardiovascular magnetic resonance;    Heart catheterization;    Image-guided intervention;    MR safety;    MR heating;    Medical devices;   

DOI  :  10.1186/s12968-015-0210-5

 received in 2015-07-05, accepted in 2015-11-19,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundConventional guidewires are not suitable for use during cardiovascular magnetic resonance (CMR) catheterization. They employ metallic shafts for mechanical performance, but which are conductors subject to radiofrequency (RF) induced heating. To date, non-metallic CMR guidewire designs have provided inadequate mechanical support, trackability, and torquability. We propose a metallic guidewire for CMR that is by design intrinsically safe and that retains mechanical performance of commercial guidewires.MethodsThe NHLBI passive guidewire is a 0.035” CMR-safe, segmented-core nitinol device constructed using short nitinol rod segments. The electrical length of each segment is less than one-quarter wavelength at 1.5 Tesla, which eliminates standing wave formation, and which therefore eliminates RF heating along the shaft. Each of the electrically insulated segments is connected with nitinol tubes for stiffness matching to assure uniform flexion. Iron oxide markers on the distal shaft impart conspicuity.Mechanical integrity was tested according to International Organization for Standardization (ISO) standards. CMR RF heating safety was tested in vitro in a phantom according to American Society for Testing and Materials (ASTM) F-2182 standard, and in vivo in seven swine. Results were compared with a high-performance commercial nitinol guidewire.ResultsThe NHLBI passive guidewire exhibited similar mechanical behavior to the commercial comparator. RF heating was reduced from 13 °C in the commercial guidewire to 1.2 °C in the NHLBI passive guidewire in vitro, using a flip angle of 75°. The maximum temperature increase was 1.1 ± 0.3 °C in vivo, using a flip angle of 45°. The guidewire was conspicuous during left heart catheterization in swine.ConclusionsWe describe a simple and intrinsically safe design of a metallic guidewire for CMR cardiovascular catheterization. The guidewire exhibits negligible heating at high flip angles in conformance with regulatory guidelines, yet mechanically resembles a high-performance commercial guidewire. Iron oxide markers along the length of the guidewire impart passive visibility during real-time CMR. Clinical translation is imminent.

【 授权许可】

CC BY   
© Basar et al. 2015