Medical imaging
DICOM packaging, retained and removed tags, report format, pseudonymous IDs and the study manifest.
Radiology is licensed as studies, not loose images: full DICOM series with the radiology report, and EMR where the source can link it. Everything is de-identified before it leaves the site.
Packaging
One folder per study, a subfolder per series, and the report beside the images.
QD-9M4R/manifest.jsonlone record per studydatasheet.pdfdeid-report.pdfstudies/st_7Q2KX9M1/pseudonymous study IDstudy.jsonthe study manifestreport.txtredacted radiology reportemr.jsonwhere the site links itseries/se_01/axial, soft tissueIM_0001.dcm … IM_0412.dcmse_02/axial, lung
Tags
DICOM headers are de-identified to the PS3.15 Basic Application Level Confidentiality Profile, with the Clean Pixel Data, Clean Descriptors, Retain Longitudinal Temporal Information with Modified Dates, and Retain Patient Characteristics options.
| Kept | Removed or replaced |
|---|---|
| Modality, Body Part Examined, Study and Series Description (cleaned) | Patient Name, Other Patient IDs, Patient Address, phone numbers |
| Manufacturer, Manufacturer Model Name | Device serial numbers, station names |
| Acquisition parameters: Slice Thickness, KVP, Magnetic Field Strength, Repetition and Echo Time, Contrast agent | Institution Name and Address (region of site kept in metadata) |
| Patient Sex; age as a band | Exact birth date; Accession Number; physician and operator names |
| Pixel spacing and geometry | Burned-in text in pixel data (detected and masked) |
| Study, Series and SOP Instance UIDs, remapped consistently | Original UIDs |
Pseudonymous IDs
Each patient and study gets a stable pseudonym (pt_…, st_…) derived inside the owner's environment with a keyed hash. The key never leaves the site. The same patient keeps the same pseudonym across a dataset, so prior and follow-up studies stay linked; the pseudonym can't be reversed outside the owner's environment. Dates are shifted by a consistent offset per patient, so intervals between studies are preserved.
Reports
report.txt is the radiology report in UTF-8 plain text, with free-text redaction applied (names, dates, places, IDs replaced by tags such as [DATE]). Findings and impression are kept as written. Mammography reports carry the BI-RADS category, also lifted into study.json.
EMR fields
Where the site can link EMR, emr.json carries diagnoses (with ICD-10 codes where the source has them), relevant lab results, encounter type, follow-up studies, and biopsy outcome for mammography. All dates are shifted with the study's offset.
The study manifest
{
"study_id": "st_7Q2KX9M1",
"patient_id": "pt_K4D8N2QW",
"dataset_id": "QD-9M4R",
"modality": "CT",
"body_part": "CHEST",
"manufacturer": "SIEMENS",
"model": "SOMATOM Force",
"series": [
{ "series_id": "se_01", "description": "AXIAL SOFT TISSUE", "images": 412, "slice_thickness_mm": 1.0, "kvp": 120, "contrast": true },
{ "series_id": "se_02", "description": "AXIAL LUNG", "images": 412, "slice_thickness_mm": 1.0, "kvp": 120, "contrast": true }
],
"age_band": "50-59",
"sex": "F",
"site_region": "IN-South",
"report": "report.txt",
"emr": "emr.json",
"date_offset_applied": true
}
The values above are a specimen. Each dataset's modality mix, manufacturers and counts are on its deal sheet.