Decompress to ELE

Decompress encapsulated pixel data to Explicit VR Little Endian.

Problem

Many DICOM files use compressed transfer syntaxes (JPEG, JPEG 2000, RLE) to reduce storage size. However, some PACS systems and analysis tools only accept uncompressed Explicit VR Little Endian (ELE) format. You need to decompress the pixel data while preserving all metadata.

Steps

1. Open the compressed DICOM file — click Open files… (⌘O). Verify the current Transfer Syntax UID in the tag tree (e.g. 1.2.840.10008.1.2.4.70 for JPEG Lossless).
2. Run decompression — use the Export menu and select Export as Little Endian Explicit (uncompressed).
3. Save the output — the system produces a new DICOM file with Transfer Syntax UID 1.2.840.10008.1.2.1 (Explicit VR Little Endian) and uncompressed pixel data.
4. Verify — load the exported file. The Transfer Syntax UID shows ELE. All metadata tags are preserved. The pixel data size increases because it is now uncompressed.
5. Rendering check — the image renders identically. Lossless compressed sources (JPEG Lossless, RLE) decompress with no visual degradation.

Result

The Transfer Syntax UID becomes 1.2.840.10008.1.2.1 (Explicit VR Little Endian) and the pixels render identically to the compressed source, with all metadata preserved. The file is larger but accepted by PACS that reject compressed syntaxes.