diff --git a/pyalfe/inference.py b/pyalfe/inference.py
index 611fd8d..8ab044c 100644
--- a/pyalfe/inference.py
+++ b/pyalfe/inference.py
@@ -118,4 +118,4 @@ def predict_cases(self, input_image_tuple_list, output_list):
             if len(input_tuple) == 0:
                 raise ValueError('Empty input image tuple')
             free_surfer = FreeSurfer()
-            free_surfer.mri_synthseg(input_tuple[0], output)
+            free_surfer.mri_synthseg(input_tuple[0], output).run()