VMHC within DPARSFA pipeline

I've have a question doing VHMC within the DPARSFA pipeline. The default outputs of VHMC include both VMHC and zVMHC files. The zVMHC file seems to reflect a Z-transform of the VMHC file, performed on every voxel inside a default brain mask. However, the default mask includes the midline slice that has perfect correlation with itself. Is there a way to exclude the midline slice from the Z-transform?

Thanks,

Jason