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Purpose To propose a MR-thermometry method and associated data processing technique to predict the maximal RF-induced temperature increase near an implanted wire for any other MRI sequence. Methods A dynamic single shot echo planar imaging sequence was implemented that interleaves acquisition of several slices every second and an energy deposition module with adjustable parameters. Temperature images were processed in real time and compared to invasive fiber-optic measurements to assess accuracy of the method. The standard deviation of temperature was measured in gel and in vivo in the human brain of a volunteer. Temperature increases were measured for different RF exposure levels in a phantom containing an inserted wire and then a MR-conditional pacemaker lead. These calibration data set were fitted to a semi-empirical model allowing estimation of temperature increase of other acquisition sequences. Results The precision of the measurement obtained after filtering with a 1.6x1.6 mm2 in plane resolution was 0.2°C in gel, as well as in the human brain. A high correspondence was observed with invasive temperature measurements during RF-induced heating (0.5°C RMSE for a 11.5°C temperature increase). Temperature rises of 32.4°C and 6.5°C were reached at the tip of a wire and of a pacemaker lead, respectively. After successful fitting of temperature curves of the calibration data set, temperature rise predicted by the model was in good agreement (around 5% difference) with measured temperature by a fiber optic probe, for three other MRI sequences. Conclusion This method proposes a rapid and reliable quantification of the temperature rise near an implanted wire. Calibration data set and resulting fitting coefficients can be used to estimate temperature increase for any MRI sequence as function of its power and duration.

High-throughput magnetic resonance imaging (MRI) tools are required for the longitudinal investigation of vascular diseases in mouse models. Angiographic data from various anatomic regions may be needed in a single experiment. This study involves a three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) method using sequential acquisitions of four data sets corresponding to the head, the thorax, the abdomen, and the hind limbs of a mouse. After repositioning the animal, each anatomic region was acquired in 2 min, and the TOF effect was provided by the spatial selectivity of the radio frequency (RF) resonator. No slab selection was needed and whole-body MRA was performed in a total experiment time of 10 min. The voxel size was equal to or greater than 131 3 195 3 188 mm 3 . To suppress the signal arising from stationary tissues, both inversion recovery and interspersed saturation, used as magnetization preparations, were compared from a theoretical and an experimental perspective. The arterial tree (carotid, aortic, iliac, renal, and smaller arteries) was well visualized by this method, both in control healthy mice and in mice with common carotid artery ligation. The potential interest of this method for evaluating arterial diseases is discussed. Magn Reson Med 66:32-39, 2011. V C 2011 Wiley-Liss, Inc.