ExportNii

exports the nii file and will prompt for a file name.

ExportNii[data,vox,"file"]

exports the nii file to the location "file"file"".

Details

NiiDataType	Automatic	NiiDataType is an option of ExportNii. The number type of Nii file can be "Integer", "Real", "Complex", or "Automatic".
CompressNii	True	CompressNii is an option for DcmToNii and ExportNii. If set True .nii.gz files will be created.
NiiOffset	Automatic	NiiOffset is an option of ExportNii. Is {xOff, yOff, zOff}.
NiiLegacy	True	NiiLegacy is an option for ExportNii, if set True default orientations are set instead of unknown.
NiiSliceCode	0	NiiSliceCode is an option for Export nii. With this you can set the slice code of the nii file.