# Loading a FFS CT Volume using "Add Data" vs "Import Dicom files"

**URL:** <https://discourse.slicer.org/t/loading-a-ffs-ct-volume-using-add-data-vs-import-dicom-files/30495>\
**Category:** Support\
**Tags:** dicom\
**Created:** [July 10, 2023, 12:33pm UTC](https://discourse.slicer.org/t/loading-a-ffs-ct-volume-using-add-data-vs-import-dicom-files/30495 "2023-07-10T12:33:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![neverpaymoney](https://avatars.discourse-cdn.com/v4/letter/n/8797f3/32.png) [@neverpaymoney](https://discourse.slicer.org/u/neverpaymoney)\
**Post date:** [July 10, 2023, 12:33pm UTC](https://discourse.slicer.org/t/loading-a-ffs-ct-volume-using-add-data-vs-import-dicom-files/30495/1 "2023-07-10T12:33:21Z")

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Hello,

I am loading a CT dicom volume using:  
**AddData**

1. “Add Data”
2. Correct display:

 ![AddData](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/b/eb00d7e4e3722926ef27fe68e356bab987eb825b.jpeg)

**ImportDicomFiles**

1. "import dicom files
2. Load Data
3. Wrong display?

 ![ImportDicom](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/8/48eb4b9c6054505edd669a102a2f4aaeef0f7f50.jpeg)

Does anyone know the reason of the difference?

Thanks.

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<div class="post-metadata">

**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [July 10, 2023, 2:33pm UTC](https://discourse.slicer.org/t/loading-a-ffs-ct-volume-using-add-data-vs-import-dicom-files/30495/2 "2023-07-10T14:33:35Z")

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Always use the DICOM module for loading DICOM data to void issues like this. Using Add Data bypasses some checks.

As it happens we are planning to make that behavior the default in the future:

> <https://github.com/Slicer/Slicer/pull/7077>
>
> Drag-and-dropping a DICOM file made Slicer use ITK DICOM reader, which often did… not load the data correctly.
> 
> This commit adds a new "DICOM import" reader type, which is selected by default for DICOM files. This reader imports the files into the Slicer DICOM database and switches to the DICOM module.
> 
> The workaround of interpreting all files as DICOM by default while in DICOM module has now been removed. "Add data" window is brought up when loading a file, regardless of what is the active module. The workaround surprised users when they could not load non-DICOM data while they were in DICOM module.
> 
> If a user wants to read the DICOM file using ITK reader, it is possible by changing "Description" in the "Add data" module to "Volume".
> 
> fixes #5726

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<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [July 10, 2023, 5:11pm UTC](https://discourse.slicer.org/t/loading-a-ffs-ct-volume-using-add-data-vs-import-dicom-files/30495/3 "2023-07-10T17:11:39Z")

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Your example shows that “Add data” loaded the data incorrectly (the orientation marker - yellow guy - is inconsistent with the image content), while the DICOM module loaded it correctly.

If you want to change the orientation of slice views then you can use the sliders in `Reformat` module.