IVIMfit: An Open-Source Python Library for Simulate and Calculate Intravoxel Incoherent Motion Parameters with Multi-Fitting Model Supports

IVIMfit is an open-source Python library aimed at model-based analysis of intravoxel incoherent motion (IVIM) in diffusion-weighted magnetic resonance imaging (DW-MRI). The library supports multiple IVIM fitting models, from monoexponential (ADC), biexponential (free and segmented) to Bayesian inference using PyMC, and triexponential models. By accepting externally provided signal decay vectors as input, IVIMfit computes physiologically meaningful diffusion and perfusion parameters that can be used in a broad variety of clinical and research settings such as oncology, nephrology, and hepatology.IVIMfit is unlike most of the available tools that are integrated tightly with GUI environments or are restricted to specific forms of the IVIM model. It is designed to be an extensible and modular backend library. The package includes built-in facilities for model fitting and parameter plotting, enabling prototyping as well as comparative evaluation of different modeling strategies. Development of IVIMfit was inspired by the need for a lightweight, scriptable, and platform-independent alternative to conventional IVIM analysis software, difficult to automate, or restricted to a fixed set of fitting methods. By facilitating straightforward access to model definitions and tunable control over the fitting process, IVIMfit allows scientists to readily experiment with and compare various fitting methods, promoting more reproducible and tunable diffusion MRI pipelines.