diff --git a/niworkflows/func/util.py b/niworkflows/func/util.py
index 0992b09df9a..b8a5955050c 100644
--- a/niworkflows/func/util.py
+++ b/niworkflows/func/util.py
@@ -6,7 +6,6 @@
 
 from nipype.pipeline import engine as pe
 from nipype.interfaces import utility as niu, fsl, afni
-from nipype.interfaces.ants.utils import AI
 
 from templateflow.api import get as get_template
 
@@ -408,6 +407,7 @@ def init_enhance_and_skullstrip_bold_wf(
     apply_mask = pe.Node(fsl.ApplyMask(), name="apply_mask")
 
     if not pre_mask:
+        from nipype.interfaces.ants.utils import AI
         from ..interfaces.nibabel import Binarize
 
         bold_template = get_template(
diff --git a/niworkflows/interfaces/fixes.py b/niworkflows/interfaces/fixes.py
index f8d45d29da6..b59b3ad4deb 100644
--- a/niworkflows/interfaces/fixes.py
+++ b/niworkflows/interfaces/fixes.py
@@ -17,7 +17,7 @@
 from .utils import _copyxform
 
 
-class FixTraitApplyTransformsInputSpec(ApplyTransformsInputSpec):
+class _FixTraitApplyTransformsInputSpec(ApplyTransformsInputSpec):
     transforms = InputMultiObject(
         traits.Either(File(exists=True), 'identity'),
         argstr="%s",
@@ -26,13 +26,15 @@ class FixTraitApplyTransformsInputSpec(ApplyTransformsInputSpec):
         "example, the last specified transform will be applied first.",
     )
 
+
 class FixHeaderApplyTransforms(ApplyTransforms):
     """
     A replacement for nipype.interfaces.ants.resampling.ApplyTransforms that
     fixes the resampled image header to match the xform of the reference
     image
     """
-    input_spec = FixTraitApplyTransformsInputSpec
+
+    input_spec = _FixTraitApplyTransformsInputSpec
 
     def _run_interface(self, runtime, correct_return_codes=(0,)):
         # Run normally
diff --git a/niworkflows/interfaces/itk.py b/niworkflows/interfaces/itk.py
index 163993bb1b5..21877dbb462 100644
--- a/niworkflows/interfaces/itk.py
+++ b/niworkflows/interfaces/itk.py
@@ -16,7 +16,7 @@
     OutputMultiObject,
     SimpleInterface,
 )
-from niworkflows.interfaces.fixes import FixTraitApplyTransformsInputSpec
+from niworkflows.interfaces.fixes import _FixTraitApplyTransformsInputSpec
 
 LOGGER = logging.getLogger("nipype.interface")
 
@@ -96,7 +96,7 @@ def _run_interface(self, runtime):
         return runtime
 
 
-class _MultiApplyTransformsInputSpec(FixTraitApplyTransformsInputSpec):
+class _MultiApplyTransformsInputSpec(_FixTraitApplyTransformsInputSpec):
     input_image = InputMultiObject(
         File(exists=True),
         mandatory=True,