Timestamps

Introduction

This document explains how Flywheel generates the session, acquisition, created, and modified timestamps.

Instruction Steps

There are a number of timestamp fields visible in your Flywheel project.

The two images below show where you can find these timestamps in your project.

In addition to these timestamps, this article also includes a section on Created At and Modified At fields.

1. Session timestamp

The goal of this timestamp is to understand when data was acquired. For DICOM files, the session timestamp is generated by the DICOM classifier gear. The classifier uses the StudyDate and StudyTime tags to generate the timestamp. If those tags are not present, Flywheel will use the earliest SeriesDate and SeriesTime. Non-DICOM data can also have a session timestamp if the Connector is configured to use a known useful timestamp for that type of data. Contact your site admin for more information about your site’s configuration.

Timestamps are stored in Flywheel with a UTC +0 offset. Add a timezone to the session to determine the local time when data was captured. This is useful when time of day is important for the study, e.g. morning CT scan vs afternoon scan.

To edit:

1. Select the Sessiontab
2. Choose a new date and time
3. Select a timezone if necessary.

1. Acquisition timestamp

For DICOM files, Flywheel uses the AcquisitionDate and AcquisitionTime tags to generate this field. SeriesDate and SeriesTime are used if the data originated from a Siemens’ imaging machine. If none of those tags can be read by Flywheel, then the session timestamp is used.

1. Created Date timestamp

The Created Date shows when the file was uploaded to Flywheel. You cannot edit these timestamps.  

1. Session label

If you do not set the session label on import, Flywheel will use the StudyDate and StudyTime tags to generate the label.  

Note: Data uploaded via the DICOM uploader uses the format "'MM-dd-yy h:mm a'" for session  labels.

To edit:

1. Click the Session tab
2. Enter a new label
3. Click **Save

**

Created At and Modified At

All files, jobs, and Gears include the Created At and Modified At fields in the Information section.

• Created At: when the file was uploaded to Flywheel or created within Flywheel.
• Modified At: This is updated anytime a change is made to the file. For example, it's updated when you move the file to a different subject, edit the file’s metadata, or run a gear against the file. If the action results in a new file version, the modified at timestamp becomes the created date for that file version

To view any file’s Created At or Modified At fields, select the  options menu next to the file, and choose Information.

Additional Timestamps Considerations

• All times are represented in your computer or browser's local time, unless accompanied by an offset (e.g. +300) or time zone (e.g. CDT).
• If you set a session to timestamp of 2022-03-10 10:34 and do not specify a timestamp, that will be understood as UTC, but the UI will present to you that time in your local timezone.
• De-identification may alter timestamps. Flywheel’s de-id profiles allow you to offset date and times when uploading your data. Contact your site admin if you do not know if your site, project, or group is using a de-id profile.
• All times visible in your project are shown in your computer or browser's local time unless accompanied by an offset (e.g. +300) or time zone (e.g. CDT).