Section: New Results

3D registration for correlative light-electron microscopy

Participants : Bertha Mayela Toledo Acosta, Patrick Bouthemy.

In recent years, correlative light and electron microscopy (CLEM) has become an attractive tool in the bio-imaging field. Biologists can collect complementary information from light microscopy (LM) and electron microscopy (EM), respectively on the dynamics and on the structure of the cell. An overlay of the LM and EM images is needed to combine information from the LM and EM sources. We are developing a 3D automated CLEM method to register EM and LM image stacks. Given the significant gap between the field of view, position and orientation of the EM and LM stacks, it is not possible to estimate directly the 3D registration. We first compute a 2D maximum intensity projection (MPI) of the LM stack along the Z-axis, and we match 2D EM regions of interest (ROI), extracted from different EM slices, into the 2D LM-MPI image. From the resulting location candidates, we estimate with a robust criterion the 2D XY-shift to pre-align the LM and EM stacks. Afterwards, a 3D affine transformation between 3D-LM-ROI and 3D-EM–ROI can be estimated using mutual information. We successfully tested this framework on two first 3D correlative microscopy datasets.

Collaborators: Xavier Heiligenstein (UMR 144 CNRS-Institut Curie),

                          Grégoire Malandain (Inria, Morpheme EPC, Sophia-Antipolis).