# Problem with mrregister

**URL:** https://community.mrtrix.org/t/problem-with-mrregister/1030
**Category:** Uncategorized
**Tags:** error
**Created:** [July 13, 2017, 1:59pm UTC](https://community.mrtrix.org/t/problem-with-mrregister/1030 "2017-07-13T13:59:52Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![maxpietsch](https://community.mrtrix.org/user_avatar/community.mrtrix.org/maxpietsch/32/25_2.png) [@maxpietsch](https://community.mrtrix.org/u/maxpietsch)
#### Post date: [July 13, 2017, 2:56pm UTC](https://community.mrtrix.org/t/problem-with-mrregister/1030/2 "2017-07-13T14:56:13Z")

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Hi Jan,

> [@jnovak](#):
>
> The error reads as such:  
> [ERROR] input images do not have the same number of dimensions

The T1 image is likely a 3D image the DWI image is a 4D image. You’d need to reduce the DWI image to a 3D image for instance by averaging across volumes (`mrmath b0_in.mif mean -axis 3 b0_out.mif`).

However, I doubt that registration will work with mrregister. Have a look in the forum for alternatives. For instance: [Registration of structural and diffusion weighted data - #7 by ElijahMak](http://community.mrtrix.org/t/registration-of-structural-and-diffusion-weighted-data/203/7)

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