Heating and safety of a new MR-compatible guidewire prototype versus a standard nitinol guidewire

• Published in: Radiological physics and technology Vol. 7; no. 1; pp. 95 - 101
• Main Authors: Wolska-Krawczyk, Malgorzata, Rube, Martin A., Immel, Erwin, Melzer, Andreas, Buecker, Arno
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.01.2014
• Subjects: Absorption; Alloys - chemistry; Aorta - pathology; Equipment Design; Ferric Compounds - chemistry; Heating; Humans; Imaging; Ketones - chemistry; Magnetic Resonance Imaging - instrumentation; Medical and Radiation Physics; Medicine; Medicine & Public Health; Models, Anatomic; Nuclear Medicine; Optical Fibers; Phantoms, Imaging; Polyethylene Glycols - chemistry; Polymers - chemistry; Radiology; Radiology, Interventional; Radiotherapy; Reproducibility of Results; Temperature; MR safety; Specific absorption rate; Radiofrequency heating
• ISSN: 1865-0333; 1865-0341
• DOI: 10.1007/s12194-013-0236-z

Our purpose in this study was to examine heating of nitinol and polyetheretherketone (PEEK) guidewires during near-real-time MR imaging in an artificial vascular model an “aorta phantom”. The first 100 cm of the nitinol- and PEEK-based guidewires both 145 × 0.08 cm were immersed in a saline-filled aorta phantom. The probes of a fiber-optic thermometer were positioned at the tips of both wires. Balanced steady-state free precession (bSSFP) [TE 1.6 ms; TR 3.5 ms; flip angle (FA) 60°; field of view (FOV) 40 cm; matrix 256 × 256; specific absorption rate (SAR); 1.15 Watt (W)/kg] and spoiled gradient-echo (SPGR) (TE 1.8 ms; TR 60 ms; FA 60°; FOV 40 cm; matrix 256 × 256; SAR 1.15 W/kg) pulse sequences were acquired in a 1.5-T MR scanner with use of an 8-channel array coil. Temperatures were recorded while the phantom was placed centrally in the bore of a MR scanner and in an off-center position ( x  = 24 cm, y  = −5 cm, z  = −10/10 cm). The temperature of the nitinol guidewire increased by 0.3 °C (center) and 1.1 °C (off-center position) with use of the bSSFP and by 9.6 and 13 °C (off-center position) with use of the SPGR sequence. Only minor temperature changes up to a maximum of 0.4 °C were observed with the MR-compatible PEEK guidewire when any position or sequence was applied. The PEEK guidewire showed substantially lower heating as compared to the nitinol guidewire in near-real-time imaging sequences in a phantom.