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

Result

Every date field shifts by the same deterministic, per-patient offset, so a patient’s studies stay correctly spaced over time. A missing Patient ID falls back to a non-zero offset rather than crashing, and missing date tags simply stay absent.