MRI active guidewire with an embedded temperature probe and providing a distinct tip signal to enhance clinical safety

Journal of Cardiovascular Magnetic Resonance

Research

Dominique N Franson¹  Christina E Saikus¹  Majdi Halabi¹  Anthony Z Faranesh¹  Ozgur Kocaturk¹  Jamie A Bell¹  Robert J Lederman¹  Merdim Sonmez²  Cengizhan Ozturk³ 

[1] Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, 20892, Bethesda, MD, USA;Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, 20892, Bethesda, MD, USA;Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey;Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey;

关键词: Specific Absorption Rate;    Introducer Sheath;    Solenoid Coil;    Insertion Length;    Radio Frequency Excitation;   

DOI  :  10.1186/1532-429X-14-38

 received in 2011-09-14, accepted in 2012-05-28,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe field of interventional cardiovascular MRI is hampered by the unavailability of active guidewires that are both safe and conspicuous. Heating of conductive guidewires is difficult to predict in vivo and disruptive to measure using external probes. We describe a clinical-grade 0.035” (0.89 mm) guidewire for MRI right and left heart catheterization at 1.5 T that has an internal probe to monitor temperature in real-time, and that has both tip and shaft visibility as well as suitable flexibility.MethodsThe design has an internal fiberoptic temperature probe, as well as a distal solenoid to enhance tip visibility on a loopless antenna. We tested different tip-solenoid configurations to balance heating and signal profiles. We tested mechanical performance in vitro and in vivo in comparison with a popular clinical nitinol guidewire.ResultsThe solenoid displaced the point of maximal heating (“hot spot”) from the tip to a more proximal location where it can be measured without impairing guidewire flexion. Probe pullback allowed creation of lengthwise guidewire temperature maps that allowed rapid evaluation of design prototypes. Distal-only solenoid attachment offered the best compromise between tip visibility and heating among design candidates. When fixed at the hot spot, the internal probe consistently reflected the maximum temperature compared external probes.Real-time temperature monitoring was performed during porcine left heart catheterization. Heating was negligible using normal operating parameters (flip angle, 45°; SAR, 1.01 W/kg); the temperature increased by 4.2°C only during high RF power mode (flip angle, 90°; SAR, 3.96 W/kg) and only when the guidewire was isolated from blood cooling effects by an introducer sheath. The tip flexibility and in vivo performance of the final guidewire design were similar to a popular commercial guidewire.ConclusionsWe integrated a fiberoptic temperature probe inside a 0.035” MRI guidewire. Real-time monitoring helps detect deleterious heating during use, without impairing mechanical guidewire operation, and without impairing MRI visibility. We therefore need not rely on prediction to ensure safe clinical operation. Future implementations may modulate specific absorption rate (SAR) based on temperature feedback.

【 授权许可】

Unknown   
© Sonmez et al.; licensee BioMed Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.