FSL

FSL is an acronym that most commonly refers to the FMRIB Software Library, a widely used suite of tools for analyzing brain imaging data. Developed by the Oxford Centre for Functional MRI of the Brain (FMRIB) at the University of Oxford, FSL supports MRI, fMRI, and diffusion MRI data and is widely used in neuroscience research.

FSL provides modules for preprocessing, statistical analysis, and segmentation. Key components include BET (Brain Extraction Tool) for skull stripping; FAST for tissue-type segmentation; FLIRT for linear image registration; FNIRT for nonlinear registration; FEAT for FMRI analysis; FIRST for subcortical structure localization; and TBSS for voxelwise analysis of diffusion data. MELODIC offers independent component analysis for identifying patterns in imaging data.

FSL runs on Unix-like systems and is commonly used on Linux computing clusters. It is primarily operated via a command-line interface, with a GUI option for some workflows, and can be scripted or integrated with other tools such as Python-based Nipype workflows.

The FSL package is freely available for academic use; licensing terms may differ for non-academic or commercial use, so researchers should review the current license terms before use.

In other contexts, FSL can refer to organizations, standards, or concepts outside neuroimaging, but this article focuses on the FMRIB Software Library.