diff --git a/nipype/interfaces/dipy/reconstruction.py b/nipype/interfaces/dipy/reconstruction.py
index a7d30be473..740c939a4c 100644
--- a/nipype/interfaces/dipy/reconstruction.py
+++ b/nipype/interfaces/dipy/reconstruction.py
@@ -211,6 +211,7 @@ def _run_interface(self, runtime):
         from dipy.reconst.csdeconv import recursive_response, auto_response
 
         img = nb.load(self.inputs.in_file)
+        imref = nb.four_to_three(img)[0]
         affine = img.get_affine()
 
         if isdefined(self.inputs.in_mask):