Add constraint for pixdim

Signed-off-by: Wei_Chuan, Chiang <[email protected]>
Co-authored-by: einsyang723 <[email protected]>
Co-authored-by: IamTingTing  <[email protected]>

Author: 3 people

monai/transforms/inverse.py

@@ -197,7 +197,8 @@ def track_transform_meta(
                 else:
                     raise
             out_obj.meta[MetaKeys.AFFINE] = convert_to_tensor(affine, device=torch.device("cpu"), dtype=torch.float64)
-            out_obj.meta[MetaKeys.PIXDIM] = affine_to_spacing(out_obj.meta[MetaKeys.AFFINE])
+            spacing = affine_to_spacing(out_obj.meta[MetaKeys.AFFINE])
+            out_obj.meta[MetaKeys.PIXDIM][1:1+len(spacing)] = spacing
 
         if not (get_track_meta() and transform_info and transform_info.get(TraceKeys.TRACING)):
             if isinstance(data, Mapping):