The MRI Simulator works through the same MRI physics that take place in a real clinical MRI scanner.
In short, we compute the signal in each spin, in each voxel, in the slice volume, for each time step. Through this we simulate the evolution of the MRI signal, and construct the image from the K-space raw data we acquire.
As such, we simulate every single image from scratch, in the same way a real scanner does. This is how we can return the same image you would expect from a real scanner, including resolution, scan time, SNR, contrast, artifacts and SAR.
Although we report the scan time it would take in real life, the simulator is extremely much faster than a real scanner.
For example, a conventional Spin echo without any turbo factor or filter may take 10 minutes in real life, while it will take less than 15 seconds on the simulator.