𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Minimizing RF heating of conducting wires in MRI

✍ Scribed by Christopher J. Yeung; Parag Karmarkar; Elliot R. McVeigh

Publisher
John Wiley and Sons
Year
2007
Tongue
English
Weight
604 KB
Volume
58
Category
Article
ISSN
0740-3194

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Performing interventions using long conducting wires in MRI introduces the risk of focal RF heating at the wire tip. Comprehensive EM simulations are combined with carefully measured experimental data to show that method‐of‐moments EM field modeling coupled with heat transfer modeling can adequately predict RF heating with wires partially inserted into the patient‐mimicking phantom. The effects of total wire length, inserted length, wire position in the phantom, phantom position in the scanner, and phantom size are examined. Increasing phantom size can shift a wire's length of maximum tip heating from about a half wave toward a quarter wave. In any event, with wires parallel to the scanner bore, wire tip heating is minimized by keeping the patient and wires as close as possible to the central axis of the scanner bore. At 1.5T, heating is minimized if bare wires are shorter than 0.6 m or between ≈2.4 m and ≈3.0 m. Heating is further minimized if wire insertion into phantoms equivalent to most aqueous soft tissues is less than 13 cm or greater than 40 cm (longer for fatty tissues, bone, and lung). The methods demonstrated can be used to estimate the absolute amount of heating in order to set RF power safety thresholds. Magn Reson Med 58:1028–1034, 2007. © 2007 Wiley‐Liss, Inc.

📜 SIMILAR VOLUMES

MRI thermometry: Fast mapping of RF-indu
MRI thermometry: Fast mapping of RF-induced heating along conductive wires
✍ Philipp Ehses; Florian Fidler; Peter Nordbeck; Eberhard D. Pracht; Marcus Warmut 📂 Article 📅 2008 🏛 John Wiley and Sons 🌐 English ⚖ 589 KB

## Abstract Conductive implants are in most cases a strict contraindication for MRI examinations, as RF pulses applied during the MRI measurement can lead to severe heating of the surrounding tissue. Understanding and mapping of these heating effects is therefore crucial for determining the circums

RF heating due to conductive wires durin
RF heating due to conductive wires during MRI depends on the phase distribution of the transmit field
✍ Christopher J. Yeung; Robert C. Susil; Ergin Atalar 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 74 KB

In many studies concerning wire heating during MR imaging, a "resonant wire length" that maximizes RF heating is determined. This may lead to the nonintuitive conclusion that adding more wire, so as to avoid this resonant length, will actually improve heating safety. Through a theoretical analysis u

RF safety of wires in interventional MRI
RF safety of wires in interventional MRI: Using a safety index
✍ Christopher J. Yeung; Robert C. Susil; Ergin Atalar 📂 Article 📅 2001 🏛 John Wiley and Sons 🌐 English ⚖ 196 KB

## Abstract With the rapid growth of interventional MRI, radiofrequency (RF) heating at the tips of guidewires, catheters, and other wire‐shaped devices has become an important safety issue. Previous studies have identified some of the variables that affect the relative magnitude of this heating bu

On the heating of linear conductive stru
On the heating of linear conductive structures as guide wires and catheters in interventional MRI
✍ Wolfgang R. Nitz; Arnulf Oppelt; Wolfgang Renz; Christoph Manke; Markus Lenhart; 📂 Article 📅 2001 🏛 John Wiley and Sons 🌐 English ⚖ 290 KB

The interest in performing vascular interventions under magnetic resonance (MR) guidance has initiated the evaluation of the potential hazard of long conductive wires and catheters. The objective of this work is to present a simple analytical approach to address this concern and to demonstrate the a

Spatial distribution of RF-induced E-fie
Spatial distribution of RF-induced E-fields and implant heating in MRI
✍ Peter Nordbeck; Florian Fidler; Ingo Weiss; Marcus Warmuth; Michael T. Friedrich 📂 Article 📅 2008 🏛 John Wiley and Sons 🌐 English ⚖ 780 KB

## Abstract The purpose of this study was to assess the distribution of RF‐induced E‐fields inside a gel‐filled phantom of the human head and torso and compare the results with the RF‐induced temperature rise at the tip of a straight conductive implant, specifically examining the dependence of the