fmri_readnii

Description

FMRI_READNII Reads a 3D or 4D NIfTI (.nii) or Analyze (.img/.hdr) file. Reads volumetric brain data and returns both the image array and a metadata structure. Works for both 3D (single volume) and 4D (time series) files. If no filename is supplied, a file-open dialog is shown.

Usage

[data, metadata] = fmri_readnii()
[data, metadata] = fmri_readnii('subject01.nii')
[data, metadata] = fmri_readnii('/path/to/data.img')

Inputs

FILENAME: Path to a .nii or .img file (string). Optional: if omitted, a file-open dialog is displayed.

Outputs

DATA: Image array. Shape: [X Y Z] for 3D, [X Y Z T] for 4D.
METADATA: Structure with fields: .hdr - Full NIfTI/Analyze header .filetype - File type code .fileprefix - Filename without extension .machine - Byte-order string .original - Original header struct

Examples

[vol, meta] = fmri_readnii('anat.nii');
[ts,  meta] = fmri_readnii('bold_run1.nii');
[vol, meta] = fmri_readnii();   % opens file dialog

Notes

This function replaces the earlier fmri_read3Dnii and fmri_read4Dnii,
which were identical. Both 3D and 4D files are handled automatically.