DICOM Metadata Viewer
Inspect every tag inside a DICOM file directly in your browser. Private, free, and instant.
How DICOM metadata viewing works in your browser
Every DICOM file (.dcm) is structured as a series of data elements, each identified by a (group,element) hexadecimal tag and a Value Representation (VR) such as PN (Person Name), DA (Date), or DS (Decimal String). The standard defines thousands of tags; vendors also add private tags within their reserved blocks. Here is exactly what happens when you load a file:
- The file is read into an ArrayBuffer using the browser's File API — no upload occurs.
- dicom-parser walks the byte stream, identifying the DICM preamble, transfer syntax, and each data element.
- Tag values are decoded according to their VR — strings are UTF-8 / ISO 8859 decoded, numbers are little-endian-converted, sequences (SQ) are recursively parsed.
- The full tag tree is rendered into a searchable table. Pixel data (7FE0,0010) is shown as a placeholder to keep memory usage low.
- The search box performs case-insensitive matching against tag code (e.g.
0010,0010), tag name (Patient Name), and value text simultaneously.
Common DICOM metadata viewer use cases
From PACS troubleshooting to de-identification audits, here is when a full-tag viewer is the right tool.
PACS administrators and IT integration troubleshooting
Inspect SOP Class UID, Modality, Transfer Syntax, and station name tags to diagnose why a study is not routing correctly through PACS, VNAs or DICOM gateways.
Researchers preparing de-identified datasets
Audit which patient identifiers (Patient Name, ID, DOB, Address, Institution) are present before running de-identification scripts. Verify removal afterward.
AI/ML engineers building imaging models
Read pixel spacing, slice thickness, manufacturer, kVp/mA, and acquisition parameters needed for input normalization and confounder analysis.
Vendors integrating with new modalities
Discover the private tags written by Siemens, GE, Philips, Canon, Hologic and Varian devices. Validate that DICOM exports comply with IHE profiles.
Patients verifying study details
Check the modality, study date, body part examined, and institution that produced your CD/USB-stick imaging — useful when sharing studies with second-opinion specialists.
Forensic and medico-legal review
Document timestamps, performing technologist, station name, software version, and image creation date for chain-of-custody and authenticity verification.
CT Read DICOM Metadata Viewer vs desktop & online alternatives
How our browser-based viewer compares to popular DICOM toolkits and other online inspectors.
| Feature | CT Read (browser, free) | dcmtk / RadiAnt / OsiriX | Other online viewers |
|---|---|---|---|
| Cost | Free, unlimited | $0–$899 | $0–$30 / month |
| Installation | None | Required | Required |
| Privacy | 100% local — no upload | Local | Server upload |
| Standard DICOM tags | Yes — all readable | Yes | Yes |
| Private vendor tags | Yes — listed with codes | Yes | Sometimes |
| Search & filter | By name / code / value | Varies | Limited |
| Sequence (SQ) expansion | Yes — recursive | Yes | Often flat |
| Mobile / tablet | Yes | No | Sometimes |
| HIPAA / GDPR friendly | Yes — files never leave device | Yes | Depends on vendor |
Technical specifications
- Input format
- DICOM Part 10 file (.dcm) — explicit & implicit VR, Little Endian / Big Endian
- Transfer syntaxes
- Most common: Implicit VR LE, Explicit VR LE, JPEG Baseline, JPEG-LS, JPEG 2000, RLE Lossless
- Tag coverage
- All groups, including private creator and private element tags
- Sequences (SQ)
- Recursively expanded — nested data sets fully visible
- Search
- Live filter by tag code (e.g., 0010,0010), name, or value
- Pixel data
- Shown as placeholder — not loaded into memory for the metadata-only view
- Browsers
- Chrome, Edge, Firefox, Safari, Opera (last 2 versions)
- Max file size
- Limited only by browser memory (typically 1–4 GB)
Privacy & security
DICOM parsing happens entirely in your browser. No file content, tag values or PHI are ever transmitted.
Browser-only parsing
We use the open-source dicom-parser library compiled to JavaScript that runs locally in your tab.
No telemetry on file content
We never see file names, tag values, patient demographics or any PHI. Only anonymous page views are logged.
Offline capable
After the page loads, you can disconnect the network. The viewer continues working perfectly.
Important limitations
- Cannot decrypt encrypted DICOM (DICOS, secure DICOM): If the file is encrypted using a vendor or institutional key, the metadata cannot be parsed. Decrypt first using the original software.
- Vendor-private tags are shown but not interpreted: Tags in the (gggg,xxxx) private space are listed with raw values, but the meaning depends on the vendor's data dictionary and is not always public.
- No editing of DICOM tags: This tool is read-only. To anonymize or modify tags, use our DICOM Anonymizer (also browser-based) or a desktop tool like dcmtk.
Frequently asked questions
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