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 realtime 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, T 1 -based thermometry is in fairly good agreement with optical fiber reference temperature. Magn Reson Med 66:448-455,