Retain Longitudinal Temporal Info
Preserve temporal relationships between studies during de-identification.
Problem
A patient has several DICOM studies spread over months or years: a baseline scan, a mid-treatment scan and a follow-up. You need to de-identify them and keep the time between them. If every date is replaced with a dummy value, you can no longer measure disease progression, treatment response or time to event. The answer is to shift all dates by one offset derived from the Patient ID, so the same patient always gets the same shift.
Steps
dcmage de-identifies one file at a time. Repeat these steps for each study of the patient, on the same installation:
- Open the study and switch to Anon mode.
- Click Auto in Date shift (preserve intervals) to derive the per-patient offset.
- Click Apply & Export.
The full workflow, including how to confirm that the offset repeats, is in DICOM date shifting.
Result
Every full date, including Patient Birth Date, moves by the same per-patient offset, so the patient’s studies keep their spacing in time. Without a Patient ID, Auto derives a non-zero offset from the file name. Date tags that are missing stay missing.