DICOM provenance and completeness
Original, Rewrapped and Reconstructed DICOM: What's the Difference?
Source DICOM is a complete file delivered by the platform and saved without changing its bytes. Rewrapping keeps a DICOM dataset as the source but changes file packaging or creates a compatibility copy. Reconstruction creates a new file from pixels and medical metadata. All may use .dcm, so the extension alone does not prove original provenance.
Four common sources
| Source | How it is obtained | Data characteristics | Before sharing with a doctor |
|---|---|---|---|
| Server-original DICOM Part 10 | Complete DICOM files supplied by the platform, saved without changing their bytes. | Pixels, bit depth, tags and series depend on the actual study. | Check the examination and report, and ask the receiving hospital how it accepts files. |
| Rewrapped DICOM | A standard file wrapper or compatible copy created from an existing DICOM dataset. | Check which pixels and metadata were retained. | Tell the receiving clinician that the files were rewrapped. |
| Reconstructed DICOM | New files created from image data and medical tags available on the platform. | Available information depends on the source; it cannot be assumed identical to the original. | Disclose provenance; the receiving clinician decides clinical suitability. |
| Rendered images or screenshots | JPG, PNG or screen captures of displayed images. | Usually lack the complete series and medical tags expected by a DICOM viewer. | They do not replace a complete DICOM study, but may be useful as supporting material if requested. |
Opening a file does not establish original provenance
A viewer opening the file shows format compatibility. The file may still have been rewrapped, normalized or reconstructed, and some acquisition information may be absent.
Medical Image Download distinguishes original and reconstructed files. A renamed image is not described as original DICOM. The support directory and system guides state provenance for verified entries, not every hospital using the same vendor.
Completeness checks
- Study identity: ensure files belong to the intended examination.
- Series and instances: reconcile declared and retrieved objects for missing, duplicate or conflicting identities.
- Files and pixels: check structure and readable pixels, not merely successful ZIP extraction.
- Reports: check them separately; a report alone is not a complete image study.
A DICOM instance may contain multiple frames. File counts need not equal the viewer's image count, and equal counts alone do not establish completeness.
What a SHA256 checksum proves
SHA256 helps check whether a file changed during transfer or storage. Matching digests can help detect corruption or modification.
A digest alone does not prove that every series was provided, or that the file came directly from a scanner. Use provenance, object reconciliation and file validation together.
When a doctor requests original imaging
- Check the file provenance, examination date and series in the task result. To see whether files open, select a local ZIP, folder or .dcm file in our free online DICOM viewer or a compatible desktop viewer. A preview, bit depth or HU value alone cannot prove original provenance.
- Keep the complete study folder and available report. Ask the receiving hospital whether it accepts USB drives, discs or a designated upload portal and which file formats it requires.
- If the delivered result is reconstructed but source files are required, ask the imaging hospital how to request the originals.
Technical checks do not certify clinical suitability; the receiving clinician decides whether the material meets the current need.
Frequently asked questions
Is every .dcm file original DICOM?
No. Original, rewrapped and reconstructed files may all use .dcm. Check the source and processing information.
Can renaming JPG to .dcm restore original imaging?
No. Changing an extension does not create a complete DICOM dataset or restore missing pixels, series or acquisition parameters.
Is reconstruction the same as wrapping a screenshot?
Not necessarily. Full-resolution platform pixels and medical tags provide different input from a screenshot. Neither should be misrepresented as server-original files.
Does a different file count prove that images are missing?
No. A DICOM instance can contain multiple frames. Reconcile the platform's study, series, instance and frame definitions instead of comparing file totals alone.