# Split Scalar Volume into Multiple Frames

**URL:** <https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490>\
**Category:** Support\
**Tags:** multivolume\
**Created:** [September 15, 2020, 1:49pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490 "2020-09-15T13:49:08Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Fluvio\_Lobo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fluvio_lobo/32/81262_2.png) [@Fluvio\_Lobo](https://discourse.slicer.org/u/Fluvio_Lobo)\
**Post date:** [September 15, 2020, 1:49pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/1 "2020-09-15T13:49:08Z")

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Hello,

I am trying to split scalar-DICOM volume, with multiple frames, so that I can create multiple volumes.  
I am trying to do this because the multi-volume exporter does not seem to recognize the input volume as a multi-volume.

**UPDATE:** _Just checked, these DICOMs I am having issues with lack the “trigger time” tag on the metadata/headers. I compared them to some that do import as multi-volumes_

Thoughts?

 ![issue](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/f/3f20479c42cbf153a4b50298a4d23ebab4528faf.png)

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**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:** [September 15, 2020, 5:36pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/2 "2020-09-15T17:36:49Z")

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These are the fields that we currently recognize as fields that may be used to split a volume:

> <https://github.com/fedorov/MultiVolumeImporter/blob/8a81b4395e9093875b0f90a3a1b479b0832f8c36/MultiVolumeImporterPlugin.py#L37-L57>

We are making adjustments, add more tags as we encounter valid data sets that are not recognized.  
Could you try if latest Slicer Preview Release can recognize it as a time sequence?

If the latest version does not recognize your data but you believe that your data set is correct and complete (e.g., DICOM tags were removed by too aggressive anonymization) then we can see if we can add one more tag to split by.

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<div class="post-metadata">

**Author:** ![Fluvio\_Lobo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fluvio_lobo/32/81262_2.png) [@Fluvio\_Lobo](https://discourse.slicer.org/u/Fluvio_Lobo)\
**Post date:** [September 15, 2020, 6:33pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/3 "2020-09-15T18:33:54Z")

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@lassoan,

Thank you for the response!

First, let me clarify that I must have done something weird before when reading the metadata. If I import the dataset alone, I do read “trigger time” in the metadata

 ![trigger_value](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/1/f1ee5656d23b030f2b337b72ab18c92ded158231.png)

As expected (I believe), there are about 9 values for trigger time. I am estimating about 9 frames per slice. The values are [0, 61443, 122886, 184328, 245771, 307213.99, 368657.01, and 430099]

If I use the **MultiVolumeImporter** , I get a “multivolume” named “664 frames MultiVolume.” I then use the **MultiVolumeExplorer** to copy a specific frame, the it seems to only get a single frame and not the entire sequence!

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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:** [September 15, 2020, 6:35pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/4 "2020-09-15T18:35:02Z")

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Do not use MultiVolumeImporter module for this. You should be able to simply load the data set using DICOM module.

Can you share the data set? (make sure it is anonymized, animal, or phantom)

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<div class="post-metadata">

**Author:** ![Fluvio\_Lobo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fluvio_lobo/32/81262_2.png) [@Fluvio\_Lobo](https://discourse.slicer.org/u/Fluvio_Lobo)\
**Post date:** [September 15, 2020, 6:47pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/5 "2020-09-15T18:47:59Z")

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@lassoan,

I am adding the data [here](https://app.box.com/s/p3vm4eztkb78s4sfbi7sza4ukpwp3rme)  
The data is from [The Cancer Image Archive](https://www.cancerimagingarchive.net/)  
As far as I know, it has been properly anonymized

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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:** [September 15, 2020, 8:54pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/6 "2020-09-15T20:54:25Z")

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Multi-volumes can only be imported if the volumes form hypercubes (all timepoints have the same geometry). In this data set, 84 slices are found for TriggerTime=[0.0], 82 slices are found for TriggerTime=[61443.0], and 83 slices are found for TriggerTime=[122886.0, 184328.0, 245771.0, 307213.99, 368657.01, 430099.0].

There may be an issue with the data set and so it may be safer to reject it.

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<div class="post-metadata">

**Author:** ![Fluvio\_Lobo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fluvio_lobo/32/81262_2.png) [@Fluvio\_Lobo](https://discourse.slicer.org/u/Fluvio_Lobo)\
**Post date:** [September 15, 2020, 9:09pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/7 "2020-09-15T21:09:13Z")

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@lassoan,

Wow, that is very random. I think this could very well be an issue with the dataset. I have been going through other datasets and found nothing similar, everything is importing fine.

I have to go through about 10 more, so I will be sure to follow-up and tell you if the error occurred again.

Thank you!

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<div class="post-metadata">

**Author:** ![Fluvio\_Lobo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fluvio_lobo/32/81262_2.png) [@Fluvio\_Lobo](https://discourse.slicer.org/u/Fluvio_Lobo)\
**Post date:** [September 17, 2020, 1:39pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/8 "2020-09-17T13:39:35Z")

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@lassoan,

I can confirm that it was some download error from the TCIA database. I re-downloaded the two datasets that had this issue and Slicer properly recognized them as multivolumes.

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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:** [September 17, 2020, 1:42pm UTC](https://discourse.slicer.org/t/split-scalar-volume-into-multiple-frames/13490/9 "2020-09-17T13:42:55Z")

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Thank you, this is very useful feedback. It indicates that (at least in some cases) it makes sense to be strict and reject suspicious data sets instead of being more tolerant for errors.