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RF-induced Heating of Interventional Devices at 23.66 MHz

Overview
Journal MAGMA
Publisher Springer
Date 2023 May 17
PMID 37195365
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Abstract

Objective: Low-field MRI systems are expected to cause less RF heating in conventional interventional devices due to lower Larmor frequency. We systematically evaluate RF-induced heating of commonly used intravascular devices at the Larmor frequency of a 0.55 T system (23.66 MHz) with a focus on the effect of patient size, target organ, and device position on maximum temperature rise.

Materials And Methods: To assess RF-induced heating, high-resolution measurements of the electric field, temperature, and transfer function were combined. Realistic device trajectories were derived from vascular models to evaluate the variation of the temperature increase as a function of the device trajectory. At a low-field RF test bench, the effects of patient size and positioning, target organ (liver and heart) and body coil type were measured for six commonly used interventional devices (two guidewires, two catheters, an applicator and a biopsy needle).

Results: Electric field mapping shows that the hotspots are not necessarily localized at the device tip. Of all procedures, the liver catheterizations showed the lowest heating, and a modification of the transmit body coil could further reduce the temperature increase. For common commercial needles no significant heating was measured at the needle tip. Comparable local SAR values were found in the temperature measurements and the TF-based calculations.

Conclusion: At low fields, interventions with shorter insertion lengths such as hepatic catheterizations result in less RF-induced heating than coronary interventions. The maximum temperature increase depends on body coil design.

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References
1.
Bock M, Wacker F . MR-guided intravascular interventions: techniques and applications. J Magn Reson Imaging. 2008; 27(2):326-38. DOI: 10.1002/jmri.21271. View

2.
Yeung C, Susil R, Atalar E . RF heating due to conductive wires during MRI depends on the phase distribution of the transmit field. Magn Reson Med. 2002; 48(6):1096-8. DOI: 10.1002/mrm.10310. View

3.
Serfaty J, Yang X, Foo T, Kumar A, Derbyshire A, Atalar E . MRI-guided coronary catheterization and PTCA: A feasibility study on a dog model. Magn Reson Med. 2003; 49(2):258-63. DOI: 10.1002/mrm.10393. View

4.
Fischbach F, Thormann M, Seidensticker M, Kropf S, Pech M, Ricke J . Assessment of fast dynamic imaging and the use of Gd-EOB-DTPA for MR-guided liver interventions. J Magn Reson Imaging. 2011; 34(4):874-9. DOI: 10.1002/jmri.22691. View

5.
Kocaturk O, Saikus C, Guttman M, Faranesh A, Ratnayaka K, Ozturk C . Whole shaft visibility and mechanical performance for active MR catheters using copper-nitinol braided polymer tubes. J Cardiovasc Magn Reson. 2009; 11:29. PMC: 2743675. DOI: 10.1186/1532-429X-11-29. View