CMRsim - A Python package for MRI simulations incorporating complex organ motion and flow

We present CMRsim, a new Python package for MR simulations efficiently incorporating complex organ motion and flow. The MR signal can be calculated using both Bloch simulations as well as analytical signal models. The package leverages TensorFlow2 for GPU acceleration and thereby facilitates fast simulations while also providing a compilation-free framework for prototyping and community contributions. Significant effort has been put on maintainability and software engineering best practices. The API reference as well as information on installation and how to get started is publicly available at: https://people.ee.ethz.ch/~jweine/cmrsim/latest/index.html Keywords: Open-source, Simulation, Cardiovascular, Motion, Reproducible science, Digital twin