By the way, the MRIcroGL "File" menu's "Save Volume" menu item does allow you to export data to Blender's bvox format. This format is limited to 8-bit precision (whereas medical images are typically 16-bit precision, so your selected contrast/brightness are "burnt in" to the output). You can look online to see how Blender can volume render voxelwise data. However recent versions of Blender have changed a lot, so old tutorials may be of limited help. Perhaps a question on a Blender forum would provide advice.