NIfTI Metadata Viewer

View metadata from .nii and .nii.gz brain imaging files. Extract shape, voxel sizes, orientation, affine matrix, statistics. Used by fMRI, DTI, structural MRI. No desktop neuroimaging suite required.

1.0.0
Version
Auth
Batch
Research / clinical data: NIfTI files from clinical subjects can be PHI. The file is parsed in memory and deleted after the response. For de-identification workflows, consider running locally with nibabel.

Upload .nii or .nii.gz file

fMRI, DTI, structural MRI, PET volumes • Max 100MB

Requires login • 2 credits

NIfTI Metadata Viewer Tutorial

What is NIfTI?

NIfTI (Neuroimaging Informatics Technology Initiative) is the standard file format for brain imaging — an improvement over ANALYZE format. Almost every fMRI dataset, DTI study, structural MRI, and PET image you'll encounter is stored as .nii or .nii.gz (gzipped).

What This Tool Shows

  • Shape — volume dimensions, e.g. (64, 64, 30) or (96, 96, 56, 120) for 4D time series
  • Voxel sizes — millimeters per voxel in X/Y/Z
  • Orientation — RAS, LAS, LPS codes for how voxel axes map to anatomy
  • Affine matrix — 4×4 matrix mapping voxel indices to world coordinates (mm)
  • Data type & statistics — intensity range, mean, standard deviation
  • Full NIfTI header dump — all fields (sizeof_hdr, intent, qform_code, descrip, etc.)

Why This Tool?

You get a NIfTI file over email / Slack / a dataset archive and you want to quickly check:

  • "What's the resolution?"
  • "How many volumes — is this 4D?"
  • "What orientation is the data in?"
  • "Is this anonymized? (checking the descrip field)"

Installing FSL, SPM, AFNI, or MRIcroGL just to run fslinfo is heavy. This does the job in a browser tab.

Pixel Data

We read the file only to extract header + compute basic intensity stats. No image slices are rendered — for that use NiiVue, MRIcroGL, or Papaya.

Format Support

  • NIfTI-1 (standard)
  • NIfTI-2 (extended for >32767 voxels per axis)
  • Uncompressed .nii and gzipped .nii.gz