Fat ViP MRI: Virtual Phantom Magnetic Resonance Imaging of water-fat systems.

Abstract Object Virtual Phantom Magnetic Resonance Imaging (ViP MRI) is a method to generate reference signals on MR images, using external radiofrequency (RF) signals. The aim of this study was to assess the feasibility of ViP MRI to generate complex-data images of phantoms mimicking water–fat systems. Materials and methods Various numerical phantoms with a given fat fraction, T 2 * and field map were designed. The k-space of numerical phantoms was converted into RF signals to generate virtual phantoms. MRI experiments were performed at 4.7 T using a multi-gradient-echo sequence on virtual and physical phantoms. The data acquisition of virtual and physical phantoms was simultaneous. Decomposition of the water and fat signals was performed using a complex-based water–fat separation algorithm. Results Overall, a good agreement was observed between the fat fraction, T 2 * and phase map values of the virtual and numerical phantoms. In particular, fat fractions of 10.5 ± 0.1 (vs 10% of the numerical phantom), 20.3 ± 0.1 (vs 20%) and 30.4 ± 0.1 (vs 30%) were obtained in virtual phantoms. Conclusion The ViP MRI method allows for generating imaging phantoms that i) mimic water–fat systems and ii) can be analyzed with water–fat separation algorithms based on complex data.