Enhance ExtractDataKeyFromMetaKeyd to work with MetaTensor

monai/apps/reconstruction/transforms/dictionary.py

@@ -12,6 +12,7 @@
 from __future__ import annotations
 
 from collections.abc import Hashable, Mapping, Sequence
+from typing import Any
 
 import numpy as np
 from numpy import ndarray
@@ -20,6 +21,7 @@
 from monai.apps.reconstruction.transforms.array import EquispacedKspaceMask, RandomKspaceMask
 from monai.config import DtypeLike, KeysCollection
 from monai.config.type_definitions import NdarrayOrTensor
+from monai.data import MetaTensor
 from monai.transforms import InvertibleTransform
 from monai.transforms.croppad.array import SpatialCrop
 from monai.transforms.intensity.array import NormalizeIntensity
@@ -57,15 +59,26 @@ def __call__(self, data: Mapping[Hashable, NdarrayOrTensor]) -> dict[Hashable, T
         Returns:
             the new data dictionary
         """
+
         d = dict(data)
+
+        meta: dict[str, Any]
+        if isinstance(d[self.meta_key], MetaTensor):
+            # meta tensor
+            meta = d[self.meta_key].meta  # type: ignore
+        else:
+            # meta dict
+            meta = d[self.meta_key]
+
         for key in self.keys:
-            if key in d[self.meta_key]:
-                d[key] = d[self.meta_key][key]  # type: ignore
+            if key in meta:
+                d[key] = meta[key]  # type: ignore
             elif not self.allow_missing_keys:
                 raise KeyError(
                     f"Key `{key}` of transform `{self.__class__.__name__}` was missing in the meta data"
                     " and allow_missing_keys==False."
                 )
+
         return d  # type: ignore
 
 

tests/apps/reconstruction/transforms/test_extract_data_key_from_meta_keyd.py

@@ -0,0 +1,39 @@
+# Copyright (c) MONAI Consortium
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#     http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import unittest
+
+from monai.apps.reconstruction.transforms.dictionary import ExtractDataKeyFromMetaKeyd
+from monai.data import MetaTensor
+
+
+class TestExtractDataKeyFromMetaKeyd(unittest.TestCase):
+    def test_extract_data_key_from_dic(self):
+        data = {"image_data": MetaTensor([1, 2, 3]), "foo_meta_dict": {"filename_or_obj": "test_image.nii.gz"}}
+
+        extract = ExtractDataKeyFromMetaKeyd("filename_or_obj", meta_key="foo_meta_dict")
+        result = extract(data)
+
+        assert data["foo_meta_dict"]["filename_or_obj"] == result["filename_or_obj"]
+
+    def test_extract_data_key_from_meta_tensor(self):
+        data = {"image_data": MetaTensor([1, 2, 3], meta={"filename_or_obj": 1})}
+
+        extract = ExtractDataKeyFromMetaKeyd("filename_or_obj", meta_key="image_data")
+        result = extract(data)
+
+        assert data["image_data"].meta["filename_or_obj"] == result["filename_or_obj"]
+
+
+if __name__ == "__main__":
+    unittest.main()