The DICOM metadata de-identification process in CHoRUS is performed in two steps:
- PatientID and AccessionNumber in teh DICOM metadata are replaced by person_id and image_occurrence_id from the OMOP table.
- Selected data tags (Table 1) are shifted by a predefined number of days (specific to each PatientID)
Table 1. Date tags to be shifted
| Group | Element | Tag_name |
|---|---|---|
| 0008 | 0012 | Instnce Createion Date |
| 0008 | 0020 | Study Date |
| 0008 | 0021 | Series Date |
| 0008 | 0022 | Acquisition Date |
| 0008 | 0023 | Content Date |
| 0008 | 002a | Acquisition Date time |
| 0010 | 0030 | Patient Birth Date |
| 0018 | 1012 | Date of Secondary Capture |
| 0018 | 1078 | Radio pharmaceutical Start Date Time |
| 0018 | 1079 | Radio pharmaceutical Stop Date Time |
| 0018 | 1200 | Date of Last Calibration |
| 0018 | 700c | Date of Last Detector Calibration |
| 0032 | 1000 | Scheduled Study Start Date |
| 0032 | 1010 | Scheduled Study Stop Date |
| 0032 | 1040 | Study Arrival Date |
| 0032 | 1050 | Study Completion Date |
| 0038 | 0020 | Admitting Date |
| 0038 | 0030 | Discharge Date |
| 3006 | 0008 | Structure Set Date |
- Remaining DICOM metadata is de-identified using the RSNA CTP software
- Pre-identifeid tags (PatientID, AccessionNumber, selected date tags in Table 1) from Step 1 are preserved