See the MRICRON project page. To use MRICRON, you’ll use the module tool.

You can see what versions are available by using:

[me@login01 ~]$ module avail mricron

------------------------------ /opt/modulefiles -------------------------------
   mricron/20190902

Use "module spider" to find all possible modules and extensions.
Use "module keyword key1 key2 ..." to search for all possible modules matching
any of the "keys".

To load a specific version, you would use:

[me@login01 ~]$ module load mricron/20190902

while the "mricron" wildcard will load the default version, mricron-20190902 in this case.

You should now be able to run MRICRON commands:

[me@login01 ~]$ dcm2niix --version

Chris Rorden's dcm2niiX version v1.0.20190902  (JP2:OpenJPEG) GCC4.8.2 (64-bit Linux)
v1.0.20190902