Co-registration of In-Vivo Human MRI Brain Images to Postmortem Histological Microscopic Images.

Area of Science:

• Neuroimaging
• Histopathology
• Medical image analysis

Background:

• Small vascular lesions in human MRI are often only reliably detected in postmortem histological samples.
• Co-registering in-vivo MRI with postmortem microscopic features is crucial for understanding disease-specific MRI signatures.

Purpose of the Study:

• To develop and validate a method for co-registering in-vivo magnetic resonance images (MRIs) with microscopic images of postmortem brain histology.
• To improve the localization of microscopic pathological findings within the context of in-vivo imaging.

Main Methods:

• Utilized non-linear Polynomial transformation for co-registration of in-vivo MRIs to postmortem histology.
• Employed digital photographs of postmortem slices as an intermediate reference.
• Co-registered brain hemispheres separately to account for structural deformations.
• Compared various slice-matching approaches and similarity measures (Pearson correlation coefficient, mutual information).

Main Results:

• The best MRI-postmortem co-registration was achieved using four slices at a time with sequential Pearson correlation coefficient and mutual information measures.
• Evaluated accuracy by measuring 3D Euclidean distance between microscopic lesion locations and co-registered MRI locations.
• Achieved a mean 3D displacement of 5.1 ± 2.0 mm for 21 vascular lesions across 11 subjects.

Conclusions:

• The developed method enables accurate co-registration of in-vivo MRIs to postmortem histology, despite challenges from brain deformation.
• This technique provides a mean accuracy of 5.1 mm for localizing microscopic vascular lesions within in-vivo MRI data.
• The findings facilitate better interpretation of in-vivo MRI findings in relation to underlying microscopic pathology.