Virtual MRI: A PC-based simulation of a clinical MR scanner 1

Abstract

The aim of this project was to simulate the features and functions of a clinical or real-world MR scanner on a personal computer by means of a computer program. The users should be able to change all relevant settings of the virtual scanner and adapt them to the expected pathology. The algorithms of the simulation are based on parameter images of the three physical basic properties T1, T2, and proton density. From this, the synthetic images are calculated pixel by pixel on the basis of the well-known formulas of the pulse sequences chosen and modified by the user. The graphical user interface is oriented to a real-world MR scanner. The software is programmed in pure Java and is freely available under the GPL license. Besides spin echo pulse sequence, 6 other pulse sequence classes are implemented. Parameters like repetition time and echo time can be adjusted. The choice of parameters like matrix size, slice-thickness, and number of acquisitions has an impact on the signal-to-noise ratio of the images. In a first step, the simulation calculates the signal intensity in k-space. Wraparound and motion artifacts are simulated by modifying the data of k-space. In a last step, a 2D-Fourier transform of k-space data is performed. As the image calculation takes only a few seconds, an interactive manner of working is possible. The simulation has been used in the education of medical students and interns for more than 1 year and has gained widespread acceptance.