diff --git a/fsl/data/image.py b/fsl/data/image.py
index 174e1746b5af8ec93f8b48edb63f461f9af21df6..77889897f2610ac6d5735c81ffff7de85a226f40 100644
--- a/fsl/data/image.py
+++ b/fsl/data/image.py
@@ -490,6 +490,7 @@ class Nifti(notifier.Notifier, meta.Meta):
         return fileslice.canonical_slicers(sliceobj, self.__origShape)
 
 
+    @property
     def ndim(self):
         """Returns the number of dimensions in this image. This number may not
         match the number of dimensions specified in the NIFTI header, as