Retain Longitudinal Temporal Info

Preserve temporal relationships between studies during de-identification.

Problem

A patient has multiple DICOM studies spanning months or years — a baseline scan, a mid-treatment scan, and a follow-up. You need to de-identify all studies while preserving the temporal relationships between them. If you blindly zero out dates, you lose the ability to measure disease progression, treatment response, and time-to-event outcomes. The solution: shift all dates by a consistent offset derived from the Patient ID, so the same patient always gets the same shift.

Steps

See the full workflow in Date Jitter Preserve Intervals, which covers:

1. Manual date shift — enter a fixed number of days to offset all dates
2. Auto shift — click Auto to derive a deterministic offset from the Patient ID hash
3. Determinism verification — reload the file and confirm the offset is identical

Expected Result

• All date fields (Study Date, Series Date, Acquisition Date, Content Date) are shifted by the same deterministic offset.
• The same Patient ID always produces the same offset, ensuring longitudinal consistency across all studies from that patient.
• Missing Patient ID degrades gracefully — Auto shift falls back to a non-zero, non-empty offset rather than crashing or producing a zero shift.
• Missing Study Date tags do not cause errors — they simply remain absent after anonymization.