Ct2mri causes error: undefined function 'histogram_parzen'


I've installed BrainSuite and the required Matlab Compiled Runtime. Brainstorm is able to see BrainSuite and the initial checks it runs succeed, but I'm getting this error:

** Error: Line 47: Undefined function 'histogram_parzen_variable_size_multithread_double' for input arguments of type 'double'.
** Call stack:
** >histcParzen.m at 47
** >maskHeadPseudoHist.m at 75
** >register_files_affine.m at 192
** >ct2mrireg.m at 79
** >mri_coregister.m at 297
** >import_mri.m at 334
** >bst_call.m at 28
** >tree_callbacks.m>@(h,ev)bst_call(@import_mri,iSubject,[],[],1,1,'Import CT') at 576

Brainstorm version is 28-Mar-2024. Matlab is R2023a on Mac OS 12.2.1. 2016 Intel macbook pro.

Hi @aarongeller, I relay this issue with th CT2MRI developer, @Anand_Joshi, we'll solve it soon

1 Like


I have the same problem:

@Anand_Joshi, @chinmay.chinara do you have any update with respect to the binaries for macOS?

@FarzadSina, this error is not the same as the one reported in the first post of this thread. Please double-check your Brainstorm preferences it is likely you used the BrainSuite installation folder as Brainstorm temporary folder.


@Raymundo.Cassani @aarongeller: The Mac Intel binaries are updated for ct2mrireg plugin. Kindly update the plugin from the Brainstorm GUI > Plugins > Anatomy > ct2mrireg > Update and rerun the CT-MRI co-registration.

For people using Apple Silicon this issue may still persist, it will be updated in the following weeks.


Thanks! The update worked for me and I'm now able to run ct2mri.



Great to hear @aarongeller. Cheers :smile:

@Raymundo.Cassani Thanks for your response, I installed the brainsuite and python and set the installation folders in preference but happen error again.

Did you installed the MatlabRuntime R2023a that is required with BrainSuite as well?

Can you run BrainSuite alone? Run either C:\Program Files\BrainSuite23a\bin\BrainSuite23a.exe or double click on the Desktop shortcut

Edit: Corrected the runtime version

UPDATE: CT2MRIREG plugin now supports Apple Silicon.