docs/changes/newsfragments/462.feature

@@ -0,0 +1 @@
+Enable :class:`.SpaceWarper` to warp data from native space to template spaces via both FSL and ANTs by `Synchon Mandal`_

junifer/preprocess/warping/_ants_warper.py

@@ -180,27 +180,74 @@ class ANTsWarper:
 
         # Template space warping
         else:
+            input_space = input["space"]
             logger.debug(
-                f"Using ANTs to warp data from {input['space']} to {reference}"
+                f"Using ANTs to warp data from {input_space} space "
+                f"to {reference} space"
             )
 
+            # Native to MNI
+            if input_space == "native":
+                # Get warp file path
+                xfm_file_path = None
+                for entry in extra_input["Warp"]:
+                    if entry["src"] == "native" and entry["dst"] == reference:
+                        xfm_file_path = entry["path"]
+                if xfm_file_path is None:
+                    raise_error(
+                        klass=RuntimeError,
+                        msg="Could not find correct warp file path",
+                    )
+
+                # Use ResampleImage if input data resolution and reference
+                # resolution don't match
+                input_res = np.min(input["data"].header.get_zooms()[:3])
+                ref_res = np.min(
+                    input["reference"]["data"].header.get_zooms()[:3]
+                )
+                logger.debug(f"Input resolution: {input_res}")
+                logger.debug(f"Reference resolution: {ref_res}")
+                if input_res != ref_res:
+                    # Create a tempfile for resampled reference output
+                    ref_path = (
+                        element_tempdir
+                        / f"resampled_reference-{reference}.nii.gz"
+                    )
+                    # Set ResampleImage command
+                    resample_image_cmd = [
+                        "ResampleImage",
+                        "3",  # image dimension
+                        f"{input['reference']['path'].resolve()}",
+                        f"{ref_path.resolve()}",
+                        f"{input_res}x{input_res}x{input_res}",
+                        "0",  # option for spacing and not size
+                        "3 3",  # Lanczos windowed sinc
+                    ]
+                    # Call ResampleImage
+                    run_ext_cmd(name="ResampleImage", cmd=resample_image_cmd)
+                else:
+                    logger.debug(
+                        "Reference resolution matches input resolution"
+                    )
+                    ref_path = input["reference"]["path"]
+
+            # MNI to MNI
+            else:
                 # Get xfm file
-            xfm_file_path = get_xfm(src=input["space"], dst=reference)
-            # Get template space image
+                xfm_file_path = get_xfm(src=input_space, dst=reference)
+                # Get template space image in correct resolution
                 template_space_img = get_template(
                     space=reference,
                     target_img=input["data"],
                     extra_input=None,
                 )
                 # Save template
-            template_space_img_path = (
-                element_tempdir / f"{reference}_T1w.nii.gz"
-            )
-            nib.save(template_space_img, template_space_img_path)
+                ref_path = element_tempdir / f"{reference}_T1w.nii.gz"
+                nib.save(template_space_img, ref_path)
 
             # Create a tempfile for warped output
             warped_output_path = element_tempdir / (
-                f"warped_data_from_{input['space']}_to_{reference}.nii.gz"
+                f"warped_data_from_{input_space}_to_{reference}.nii.gz"
             )
 
             # Set antsApplyTransforms command
@@ -210,7 +257,7 @@ class ANTsWarper:
                 "-e 3",
                 "-n LanczosWindowedSinc",
                 f"-i {input['path'].resolve()}",
-                f"-r {template_space_img_path.resolve()}",
+                f"-r {ref_path.resolve()}",
                 f"-t {xfm_file_path.resolve()}",
                 f"-o {warped_output_path.resolve()}",
             ]
@@ -226,18 +273,20 @@ class ANTsWarper:
                     "data": nib.load(warped_output_path),
                     # Update warped input's space
                     "space": reference,
-                    # Save reference path
-                    "reference": {"path": template_space_img_path},
+                    # Save resampled reference path or overwrite original
+                    # keeping it same
+                    "reference": {"path": ref_path},
                     # Keep pre-warp space for further operations
-                    "prewarp_space": input["space"],
+                    "prewarp_space": input_space,
                 }
             )
 
             # Check for data type's mask and warp if found
             if input.get("mask") is not None:
+                logger.debug("Warping associated mask")
                 # Create a tempfile for warped mask output
                 apply_transforms_mask_out_path = element_tempdir / (
-                    f"warped_mask_from_{input['space']}_to_{reference}.nii.gz"
+                    f"warped_mask_from_{input_space}_to_{reference}.nii.gz"
                 )
                 # Set antsApplyTransforms command
                 apply_transforms_mask_cmd = [
@@ -246,8 +295,8 @@ class ANTsWarper:
                     "-e 3",
                     "-n 'GenericLabel[NearestNeighbor]'",
                     f"-i {input['mask']['path'].resolve()}",
-                    # use resampled reference
-                    f"-r {input['reference']['path'].resolve()}",
+                    # use resampled reference or original
+                    f"-r {ref_path.resolve()}",
                     f"-t {xfm_file_path.resolve()}",
                     f"-o {apply_transforms_mask_out_path.resolve()}",
                 ]

junifer/preprocess/warping/_fsl_warper.py

@@ -40,6 +40,7 @@ class FSLWarper:
         self,
         input: dict[str, Any],
         extra_input: dict[str, Any],
+        reference: str,
     ) -> dict[str, Any]:  # pragma: no cover
         """Preprocess using FSL.
 
@@ -50,6 +51,10 @@ class FSLWarper:
         extra_input : dict
             The other fields in the Junifer Data object. Should have ``T1w``
             and ``Warp`` data types.
+        reference : str
+            The data type or template space to use as reference for warping.
+            Template space conversion is only possible from native space,
+            not from another template space.
 
         Returns
         -------
@@ -62,6 +67,13 @@ class FSLWarper:
             If warp file path could not be found in ``extra_input``.
 
         """
+        # Create element-specific tempdir for storing post-warping assets
+        element_tempdir = WorkDirManager().get_element_tempdir(
+            prefix="fsl_warper"
+        )
+
+        # Warping to native space
+        if reference == "T1w":
             logger.debug("Using FSL for space warping")
 
             # Get the min of the voxel sizes from input and use it as the
@@ -75,12 +87,8 @@ class FSLWarper:
                     warp_file_path = entry["path"]
             if warp_file_path is None:
                 raise_error(
-                klass=RuntimeError, msg="Could not find correct warp file path"
-            )
-
-        # Create element-specific tempdir for storing post-warping assets
-        element_tempdir = WorkDirManager().get_element_tempdir(
-            prefix="fsl_warper"
+                    klass=RuntimeError,
+                    msg="Could not find correct warp file path",
                 )
 
             # Create a tempfile for resampled reference output
@@ -131,7 +139,9 @@ class FSLWarper:
             # Check for data type's mask and warp if found
             if input.get("mask") is not None:
                 # Create a tempfile for warped mask output
-            applywarp_mask_out_path = element_tempdir / "warped_mask.nii.gz"
+                applywarp_mask_out_path = (
+                    element_tempdir / "warped_mask.nii.gz"
+                )
                 # Set applywarp command
                 applywarp_mask_cmd = [
                     "applywarp",
@@ -153,11 +163,127 @@ class FSLWarper:
                             "path": applywarp_mask_out_path,
                             # Load nifti
                             "data": nib.load(applywarp_mask_out_path),
-                        # Use reference input's space as warped input mask's
-                        # space
+                            # Use reference input's space as warped input
+                            # mask's space
                             "space": extra_input["T1w"]["space"],
                         }
                     }
                 )
 
+        # Warping from native to template space
+        else:
+            logger.debug(
+                f"Using FSL to warp data from native space to {reference} "
+                "space"
+            )
+
+            # Get warp file path
+            warp_file_path = None
+            for entry in extra_input["Warp"]:
+                if entry["src"] == "native" and entry["dst"] == reference:
+                    warp_file_path = entry["path"]
+            if warp_file_path is None:
+                raise_error(
+                    klass=RuntimeError,
+                    msg="Could not find correct warp file path",
+                )
+
+            # Use flirt if input data resolution and reference resolution don't
+            # match
+            input_resolution = np.min(input["data"].header.get_zooms()[:3])
+            ref_resolution = np.min(
+                input["reference"]["data"].header.get_zooms()[:3]
+            )
+            logger.debug(f"Input resolution: {input_resolution}")
+            logger.debug(f"Reference resolution: {ref_resolution}")
+            if input_resolution != ref_resolution:
+                logger.debug("Resampling reference to match input resolution")
+                # Create a tempfile for resampled reference output
+                ref_path = (
+                    element_tempdir / f"resampled_reference-{reference}.nii.gz"
+                )
+                # Set flirt command
+                flirt_cmd = [
+                    "flirt",
+                    "-interp spline",
+                    f"-in {input['reference']['path'].resolve()}",
+                    f"-ref {input['reference']['path'].resolve()}",
+                    f"-applyisoxfm {input_resolution}",
+                    f"-out {ref_path.resolve()}",
+                ]
+                # Call flirt
+                run_ext_cmd(name="flirt", cmd=flirt_cmd)
+            else:
+                logger.debug("Reference resolution matches input resolution")
+                ref_path = input["reference"]["path"]
+
+            # Create a tempfile for warped output
+            applywarp_out_path = (
+                element_tempdir
+                / f"warped_data_from_native_to_{reference}.nii.gz"
+            )
+            # Set applywarp command
+            applywarp_cmd = [
+                "applywarp",
+                "--interp=spline",
+                f"-i {input['path'].resolve()}",
+                # use resampled reference or original
+                f"-r {ref_path.resolve()}",
+                f"-w {warp_file_path.resolve()}",
+                f"-o {applywarp_out_path.resolve()}",
+            ]
+            # Call applywarp
+            run_ext_cmd(name="applywarp", cmd=applywarp_cmd)
+
+            logger.debug("Updating warped data")
+            input.update(
+                {
+                    # Update path to sync with "data"
+                    "path": applywarp_out_path,
+                    # Load nifti
+                    "data": nib.load(applywarp_out_path),
+                    # Switch space and prewarp_space
+                    "space": reference,
+                    "prewarp_space": input["space"],
+                    # Save resampled reference path or overwrite original
+                    # keeping it same
+                    "reference": {"path": ref_path},
+                }
+            )
+
+            # Check for data type's mask and warp if found
+            if input.get("mask") is not None:
+                logger.debug("Warping associated mask")
+                # Create a tempfile for warped mask output
+                applywarp_mask_out_path = (
+                    element_tempdir
+                    / f"warped_mask_from_native_to_{reference}.nii.gz"
+                )
+                # Set applywarp command
+                applywarp_mask_cmd = [
+                    "applywarp",
+                    "--interp=nn",
+                    f"-i {input['mask']['path'].resolve()}",
+                    # use resampled reference or original
+                    f"-r {ref_path.resolve()}",
+                    f"-w {warp_file_path.resolve()}",
+                    f"-o {applywarp_mask_out_path.resolve()}",
+                ]
+                # Call applywarp
+                run_ext_cmd(name="applywarp", cmd=applywarp_mask_cmd)
+
+                logger.debug("Updating warped mask data")
+                input.update(
+                    {
+                        "mask": {
+                            # Update path to sync with "data"
+                            "path": applywarp_mask_out_path,
+                            # Load nifti
+                            "data": nib.load(applywarp_mask_out_path),
+                            # Update mask's space
+                            "space": reference,
+                        }
+                    }
+                )
+
         return input

junifer/preprocess/warping/space_warper.py

@@ -133,7 +133,7 @@ class SpaceWarper(BasePreprocessor):
         # Does not add any new keys
         return input_type
 
-    def preprocess(
+    def preprocess(  # noqa: C901
         self,
         input: dict[str, Any],
         extra_input: Optional[dict[str, Any]] = None,
@@ -162,7 +162,7 @@ class SpaceWarper(BasePreprocessor):
             i.e., using ``"T1w"`` as reference.
         RuntimeError
             If warper could not be found in ``extra_input`` when
-            ``using="auto"`` or
+            ``using="auto"`` or converting from native space or
             if the data is in the correct space and does not require
             warping or
             if FSL is used when ``reference="T1w"``.
@@ -184,6 +184,7 @@ class SpaceWarper(BasePreprocessor):
                 input = FSLWarper().preprocess(
                     input=input,
                     extra_input=extra_input,
+                    reference=self.reference,
                 )
             elif self.using == "ants":
                 input = ANTsWarper().preprocess(
@@ -204,6 +205,7 @@ class SpaceWarper(BasePreprocessor):
                     input = FSLWarper().preprocess(
                         input=input,
                         extra_input=extra_input,
+                        reference=self.reference,
                     )
                 elif warper == "ants":
                     input = ANTsWarper().preprocess(
@@ -211,10 +213,11 @@ class SpaceWarper(BasePreprocessor):
                         extra_input=extra_input,
                         reference=self.reference,
                     )
-        # Transform to template space with ANTs possible
-        elif self.using == "ants" and self.reference != "T1w":
+        # Transform to template space
+        if self.using in ["fsl", "ants"] and self.reference != "T1w":
+            input_space = input["space"]
             # Check pre-requirements for space manipulation
-            if self.reference == input["space"]:
+            if self.using == "ants" and self.reference == input_space:
                 raise_error(
                     (
                         f"The target data is in {self.reference} space "
@@ -224,20 +227,65 @@ class SpaceWarper(BasePreprocessor):
                     ),
                     klass=RuntimeError,
                 )
-
+            # Transform from native to MNI possible conditionally
+            if input_space == "native":  # pragma: no cover
+                # Check for reference as no T1w available
+                if input.get("reference") is None:
+                    raise_error(
+                        "`reference` key missing from input data type."
+                    )
+                # Check for extra inputs
+                if extra_input is None:
+                    raise_error(
+                        "No extra input provided, requires `Warp` "
+                        "data type in particular."
+                    )
+                # Warp
+                input_prewarp_space = input["prewarp_space"]
+                warper = None
+                for entry in extra_input["Warp"]:
+                    if (
+                        entry["src"] == input_space
+                        and entry["dst"] == input_prewarp_space
+                    ):
+                        warper = entry["warper"]
+                if warper is None:
+                    raise_error(
+                        klass=RuntimeError, msg="Could not find correct warper"
+                    )
+                if warper == "fsl":
+                    input = FSLWarper().preprocess(
+                        input=input,
+                        extra_input=extra_input,
+                        reference=input_prewarp_space,
+                    )
+                elif warper == "ants":
+                    input = ANTsWarper().preprocess(
+                        input=input,
+                        extra_input=extra_input,
+                        reference=input_prewarp_space,
+                    )
+                else:
+                    raise_error(
+                        klass=RuntimeError, msg="Could not find correct warper"
+                    )
+            else:
+                # Transform from MNI to MNI template space not possible
+                if self.using == "fsl":
+                    raise_error(
+                        (
+                            f"Warping from {input_space} space to "
+                            f"{self.reference} space not possible with "
+                            "FSL, use ANTs instead."
+                        ),
+                        klass=RuntimeError,
+                    )
+                # Transform from MNI to MNI template space possible
+                else:
                     input = ANTsWarper().preprocess(
                         input=input,
                         extra_input={},
                         reference=self.reference,
                     )
-        # Transform to template space with FSL not possible
-        elif self.using == "fsl" and self.reference != "T1w":
-            raise_error(
-                (
-                    f"Warping to {self.reference} space not possible with "
-                    "FSL, use ANTs instead."
-                ),
-                klass=RuntimeError,
-            )
 
         return input, None