brainmesh_handler

brainmesh_handler.patch

diff --git a/invesalius/data/brainmesh_handler.py b/invesalius/data/brainmesh_handler.py
index 172b3c3a..a6f6732b 100644
--- a/invesalius/data/brainmesh_handler.py
+++ b/invesalius/data/brainmesh_handler.py
@@ -33,6 +33,8 @@ class Brain:
         tmpPeel = downsample(refSurface)
         # Standard space coordinates
         mask_sFormMatrix = mask_reader.GetSFormMatrix()
+        if mask_sFormMatrix is None:
+            mask_sFormMatrix = vtk.vtkMatrix4x4()
 
         # Apply coordinate transform to the meshed mask
         mask_ijk2xyz = vtk.vtkTransform()
@@ -58,6 +60,8 @@ class Brain:
 
         # Scanner coordinates from image
         qFormMatrix = T1_reader.GetQFormMatrix()
+        if qFormMatrix is None:
+            qFormMatrix = vtk.vtkMatrix4x4()
 
         refImageSpace2_xyz_transform = vtk.vtkTransform()
         refImageSpace2_xyz_transform.SetMatrix(qFormMatrix)