Convert NII.GZ to DWF

Technical note

NII.GZ to DWF: what carries over and what does not

The standard NII.GZ header has no fields for a patient's name, birth date or accession number, only an 80-character free-text description, which is one reason research pipelines convert DICOM to NIfTI before data is shared. That does not make every output anonymous. A head scan contains the face, and a 3D rendering of the volume can reconstruct it well enough to recognise someone, which is why public datasets are usually defaced first. Slices that pass through the front of the head carry the same risk. How good the result is depends almost entirely on the NII.GZ going in. Clean line art, a logo or a drawing scanned at 300 dpi or more traces into geometry you can work with. A photograph does not: continuous tone has no contours to follow, so tracing it produces thousands of tiny shapes and a file nobody can edit. Scan or export at the highest resolution available, and prefer a lossless original, because compression artefacts along an edge become ripples in the traced path.