# DTI Nifti data from the HCP import via DWI Convert Module

**URL:** <https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330>\
**Category:** Support\
**Created:** [March 28, 2019, 4:36pm UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330 "2019-03-28T16:36:32Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![Bebo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bebo/32/3614_2.png) [@Bebo](https://discourse.slicer.org/u/Bebo)\
**Post date:** [March 28, 2019, 4:36pm UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/1 "2019-03-28T16:36:32Z")

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Hello every one,

I’m using 3D Slicer 4.10.1. I’m currently trying to convert DTI Nifti data from the HCP import via DWI Convert Module (the data come from [http://www.humanconnectomeproject.org/](http://www.humanconnectomeproject.org/)).  
However I have this error message:

Diffusion-weighted DICOM Import (DWIConvert) standard error:  
Error: ReadVolume: Unsupported source pixel type.  
Input volume: float  
Output volume: short  
The only supported output type is . You may consider using allowLossyConversion option.  
However, use this option with caution! Conversion from images of a different type may cause data loss due to rounding or truncation.

The bval. and .bvec files originally came in .txt format  
Does someone have a clue ?

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**Author:** ![zhangfanmark](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/zhangfanmark/32/4451_2.png) [@zhangfanmark](https://discourse.slicer.org/u/zhangfanmark)\
**Post date:** [March 28, 2019, 5:06pm UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/2 "2019-03-28T17:06:20Z")

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Hi,

Have you tried to use allowLossyConversion as suggested by DWIConvert.

For our processing of the HCP data, we use this option.

Regards,  
Fan

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**Author:** ![Bebo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bebo/32/3614_2.png) [@Bebo](https://discourse.slicer.org/u/Bebo)\
**Post date:** [March 29, 2019, 8:52am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/3 "2019-03-29T08:52:31Z")

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Hi @zhangfanmark,  
Yes I did, I even tried all possible combinations of options.  
I noticed that every time I used the lossy option, the DWIconvert window pops up explaining that it crashed but I have no longer the message explaning the possible sources of error  
“Diffusion-weighted DICOM Import (DWIConvert) standard error:  
Error: ReadVolume: Unsupported source pixel type…”

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**Author:** ![ljod](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ljod/32/652_2.png) [@ljod](https://discourse.slicer.org/u/ljod)\
**Post date:** [March 29, 2019, 9:33am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/4 "2019-03-29T09:33:35Z")

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Hi what version of Slicer are you using?

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**Author:** ![Bebo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bebo/32/3614_2.png) [@Bebo](https://discourse.slicer.org/u/Bebo)\
**Post date:** [March 29, 2019, 9:45am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/5 "2019-03-29T09:45:41Z")

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Hi @ljod,  
I’m using Slicer 4.10.1 version

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**Author:** ![ljod](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ljod/32/652_2.png) [@ljod](https://discourse.slicer.org/u/ljod)\
**Post date:** [April 2, 2019, 5:48pm UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/6 "2019-04-02T17:48:39Z")

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Hi I think Fan can get back to you about how he processed the data when his conference paper is submitted today.@zhangfanmark

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**Author:** ![Bebo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bebo/32/3614_2.png) [@Bebo](https://discourse.slicer.org/u/Bebo)\
**Post date:** [April 3, 2019, 8:13am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/7 "2019-04-03T08:13:37Z")

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Hi @ljod,  
I have no explanation about why it worked this time… Few days ago, I registered to the other human connectome project ([https://www.humanconnectome.org/](https://www.humanconnectome.org/)) and I did the same manipulations, using the “allowLossyConversion” option as @zhangfanmark mentionned. Finally it worked this time…  
I don’t know if initially the data was corrupted, but in case @ljod @zhangfanmark thank you for the advice!

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**Author:** ![hercp](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@hercp](https://discourse.slicer.org/u/hercp)\
**Post date:** [August 10, 2020, 3:14am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/8 "2020-08-10T03:14:13Z")

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Nicolas,

What exactly did you do to make this work?

HP

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**Author:** ![Tamires\_Zanao](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/tamires_zanao/32/10306_2.png) [@Tamires\_Zanao](https://discourse.slicer.org/u/Tamires_Zanao)\
**Post date:** [March 16, 2021, 10:36am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/9 "2021-03-16T10:36:52Z")

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Hi! First, I also had this issue with DWIConvert, but it worked using allowLossyConversion. However, I cannot open the .nhdr file on Slicer. Do you know what could be wrong? Thanks!

Best,  
Tamires

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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:** [March 26, 2021, 3:25am UTC](https://discourse.slicer.org/t/dti-nifti-data-from-the-hcp-import-via-dwi-convert-module/6330/10 "2021-03-26T03:25:18Z")

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If you can provide an example .nhdr and corresponding .raw file then we can help investigating the issue.