Assessment of Radiofrequency Self-Heating Around a Metallic Wire With MR T1-Based Thermometry

Heat produced by a magnetic resonance (MR) imaging sequence in the vicinity of a conductive wire (pacemaker, electrodes, or catheter), is a subject of interest for the assessment of patient safety during imaging. For this purpose, the measurement of temperature rises during an MR imaging sequence using MR T-1-based thermometry provides several advantages, mainly in its ability to retrieve in situ real-time thermal maps. Recent studies investigated the heat produced by an independent radiofrequency pulse, assessing MR imaging sequence heating using a specific MR thermometry sequence. This study focuses on self-heating for which the radiofrequency pulses used for measuring temperature create the heat. An experimental design was set up to evaluate T-1-based thermometry self-heating using a coupled/decoupled wire and to compare it with a reference temperature gathered by an optical fiber device. For the tested experimental set up, T1-based thermometry is in fairly good agreement with optical fiber reference temperature. Magn Reson Med 66:448-455, 2011. (C) 2011 Wiley-Liss, Inc.