diff --git a/darwin/exporter/formats/nifti.py b/darwin/exporter/formats/nifti.py
index c6c4e5168..c23aaac48 100644
--- a/darwin/exporter/formats/nifti.py
+++ b/darwin/exporter/formats/nifti.py
@@ -83,7 +83,9 @@ def export(
             medical_metadata = video_annotation.slots[0].metadata
             legacy = not medical_metadata.get("handler") == "MONAI"  # type: ignore
             plane_map = medical_metadata.get("plane_map", {slot_name: "AXIAL"})
-            primary_plane = plane_map.get(slot_name, "AXIAL")
+            primary_plane = medical_metadata.get(
+                "primary_plane", plane_map.get(slot_name, "AXIAL")
+            )
         except (KeyError, AttributeError):
             legacy = True
             primary_plane = "AXIAL"
diff --git a/tests/darwin/exporter/formats/export_nifti_test.py b/tests/darwin/exporter/formats/export_nifti_test.py
index 5641b883a..cec352648 100644
--- a/tests/darwin/exporter/formats/export_nifti_test.py
+++ b/tests/darwin/exporter/formats/export_nifti_test.py
@@ -1,6 +1,6 @@
 import tempfile
 from pathlib import Path
-from unittest.mock import patch, MagicMock
+from unittest.mock import patch, MagicMock, ANY
 from zipfile import ZipFile
 
 import nibabel as nib
@@ -129,12 +129,19 @@ def test_export_calls_populate_output_volumes_from_raster_layer(
                 / team_slug_darwin_json_v2
                 / "nifti/releases/latest/annotations"
             )
-            video_annotation_filepaths = [annotations_dir / "mask_only.json"]
+            video_annotation_filepaths = [annotations_dir / "non_axial_mask_only.json"]
             video_annotations = list(
                 darwin_to_dt_gen(video_annotation_filepaths, False)
             )
             nifti.export(video_annotations, output_dir=Path(tmpdir))
             mock.assert_called()
+            mock.assert_called_with(
+                annotation=ANY,
+                mask_id_to_classname=ANY,
+                slot_map=ANY,
+                output_volumes=ANY,
+                primary_plane="CORONAL",
+            )
 
 
 def test_export_creates_file_for_polygons_and_masks(
diff --git a/tests/data.zip b/tests/data.zip
index cd5a2f149..e1f414e8e 100644
Binary files a/tests/data.zip and b/tests/data.zip differ