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Introduction

Biobank radiology imaging data on TCIA contains the “days from enrollment (registration)” for each scan, embedded in the DICOM files (DICOM tag (0012,0053)).   This allows for temporal alignment between the imaging on TCIA and clinical events data found on the Biobank Catalog.
Note:  In order that the images display properly in DICOM readers, the radiology imaging data also contains de-identified dates that preserve the temporal sequence relationship between scans in a given study.

Days from enrollment (registration) 

In addition to modifying the actual date fields in the DICOM header, the "days from registration" values are calculated and stored in the DICOM tag (0012,0052) Longitudinal Temporal Offset from Event with the associated tag (0012,0053) Longitudinal Temporal Event Type set to “REGISTRATION”.   Here is an example DICOM header from a scan where the patient's imaging was performed 2 days before the registration, resulting in a negative offset value.

If you would like to filter your search results using this information, you can leverage the "Clinical Trial Time Points" filter  via our data portal at https://nbia.cancerimagingarchive.net/nbia-search/. 

Image Added

De-identification of DICOM dates

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For example, if the real date of a patient's registration was 03/27/2018 and the original imaging Study Date was 03/29/2018 then the anonymized TCIA Study Date would become 01/03/1960 (two days after the base date of 1/1/1960).

Insertion of computed "REGISTRATION"/Days offset from registration" value

In addition to modifying the actual date fields in the DICOM header, the "days from registration" values are calculated and stored in the DICOM tag (0012,0052) Longitudinal Temporal Offset from Event with the associated tag (0012,0053) Longitudinal Temporal Event Type set to “REGISTRATION”.   Here is an example DICOM header from a scan where the patient's imaging was performed 2 days before the registration, resulting in a negative offset value.

If you would like to filter your search results using this information you can leverage the "Clinical Trial Time Points" filter shown below via our data portal at https://nbia.cancerimagingarchive.net/nbia-search/. 

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