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.

Expected Result

• Transfer Syntax UID changes to 1.2.840.10008.1.2.1 (Explicit VR Little Endian).
• All DICOM metadata tags are preserved unchanged.
• Pixel data renders identically to the compressed source.
• File size is larger (uncompressed pixel data).
• Decompressed file is accepted by PACS systems that reject compressed syntaxes.