Spatial correspondence between histology and multi sequence MRI can provide information about the capabilities of
non-invasive imaging to characterize cancerous tissue. However, shrinkage and deformation occurring during the
excision of the tumor and the histological processing complicate the co registration of MR images with histological
sections. This work proposes a methodology to establish a detailed 3D relation between histology sections and in vivo
MRI tumor data. The key features of the methodology are a very dense histological sampling (up to 100 histology slices
per tumor), mutual information based non-rigid B-spline registration, the utilization of the whole 3D data sets, and the
exploitation of an intermediate ex vivo MRI.
In this proof of concept paper, the methodology was applied to one tumor. We found that, after registration, the visual
alignment of tumor borders and internal structures was fairly accurate. Utilizing the intermediate ex vivo MRI, it was
possible to account for changes caused by the excision of the tumor: we observed a tumor expansion of 20%. Also the
effects of fixation, dehydration and histological sectioning could be determined: 26% shrinkage of the tumor was found.
The annotation of viable tissue, performed in histology and transformed to the in vivo MRI, matched clearly with high
intensity regions in MRI. With this methodology, histological annotation can be directly related to the corresponding in
vivo MRI. This is a vital step for the evaluation of the feasibility of multi-spectral MRI to depict histological groundtruth.