NIfTI — Neuroimaging Informatics Technology Initiative File Format

Overview

NIfTI (.nii / .nii.gz) is the standard file format for storing processed neuroimaging data, including structural MRI, functional MRI, diffusion MRI, and PET volumes. Developed in 2004 by a NIH-convened working group to replace the fragmented ANALYZE 7.5 format, NIfTI is widely supported across neuroimaging analysis tools. It carries spatial coordinate and orientation information essential for cross-study alignment to standard brain spaces, has no proprietary dependencies, and is produced from DICOM scanner output. NIfTI-2 (2011) extended the format to support the large array dimensions required by high-resolution and high-temporal-resolution datasets.

Connections

• Converted from: DICOM
• Required by: BIDS (mandatory MRI and PET image format)

Resources

• https://nifti.nimh.nih.gov
• https://nifti.nimh.nih.gov/nifti-1 (NIfTI-1 specification)
• https://nifti.nimh.nih.gov/nifti-2 (NIfTI-2 specification)