What units of RT tedana expects?

1

Dear all,

I’m trying to setup a tedana pipeline for my multi-echo dataset and I discovered that tedana expects that I pass the repetition time (TR) in the Nifti header of my images. Looking how to include the TR into header, I found a contradicting information:

Nibabel says (in the get_zooms) that units are miliseconds:

The last value of header.get_zooms() is the time between scans in milliseconds; this is the equivalent of voxel size on the time axis.

Code snipet that Tedana references if TR == 0 says that units are seconds:

The TR that the data should have IN SECONDS

Which one is right? For using tedana, should I put seconds or miliseconds?

2

I believe the nibabel documentation is wrong. The units of the zooms can be determined with img.header.get_xyzt_units(). Tedana will want the units in seconds, but I think it’s only used for plotting- I don’t think tedana calculates any metrics or classifies any components using the TR.

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3

Thanks)

Tried get_xyzt_units, and it returned ‘sec’ in my case, so there’s no ambiguity.

I found that strange that tedana require the TR n the header and uses it only for plotting, but anyway now my problem is solved. Thanks again.

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