Julien Sénégas

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Compressed sensing (CS) holds considerable promise to accelerate the data acquisition in magnetic resonance imaging by exploiting signal sparsity. Prior knowledge about the signal can be exploited in some applications to choose an appropriate sparsifying transform. This work presents a CS reconstruction for magnetic resonance (MR) parameter mapping, which(More)
Signal dephasing due to field inhomogeneity and signal decay due to transverse relaxation lead to perturbations of the Fourier encoding commonly applied in magnetic resonance imaging. Hence, images acquired with long readouts suffer from artifacts such as blurring, distortion, and intensity variation. These artifacts can be removed in reconstruction,(More)
PURPOSE To develop a method for visualizing surgical textile implant (STI) with superparamagnetic iron oxides (SPIO), using magnetic resonance imaging (MRI). Therefore, positive-contrast inversion-recovery with on-resonant water suppression (IRON) was applied and its properties were evaluated in vitro. MATERIALS AND METHODS STI with different(More)
Prostate T(2) mapping was performed in 34 consecutive patients using an accelerated multiecho spin-echo sequence with 4-fold k-space undersampling leading to a net acceleration factor of 3.3 on a 3T scanner. The mean T(2) values from the accelerated and conventional, unaccelerated sequences demonstrated a very high correlation (r = 0.99). Different prostate(More)
PURPOSE T2-weighted magnetic resonance imaging (MRI) is commonly used for anatomical visualization in the pelvis area, such as the prostate, with high soft-tissue contrast. MRI can also provide functional information such as diffusion-weighted imaging (DWI) which depicts the molecular diffusion processes in biological tissues. The combination of anatomical(More)
This work presents a novel method for the rapid and simultaneous measurement of R1 and R2* relaxation rates. It is based on a dynamic short repetition time steady-state spoiled multigradient-echo sequence and baseline R1 and B1 measurements. The accuracy of the approach was evaluated in simulations and a phantom experiment. The sensitivity and specificity(More)
Introduction: The estimation of MR parameters, such as the relaxation times T1, T2 and diffusion coefficients D, requires the acquisition of multiple images at different sequence parameters, which is often associated with long acquisition times. These data show a high temporal correlation, which can be described by a model facilitating accelerated image(More)
PURPOSE To compare Rician and non-Rician noise models for quantitative R2 * magnetic resonance imaging (MRI), in a simulation, phantom, and human study. MATERIALS AND METHODS Synthetic 12-echo spoiled GRE (SGRE) datasets were generated with various R2 * rates (0-2000 sec(-1) ) at a signal-to-noise ratio (SNR) of 50, 20, 10, and 5. Phantoms of different(More)