Three-dimensional registration of magnetic resonance image data to histological sections with model-based evaluation.

We developed a three-dimensional (3D) registration method to align medical scanner data with histological sections. After acquiring 3D medical scanner images, we sliced and photographed the tissue using, a custom apparatus, to obtain a volume of tissue section images. Histological samples from the sections were digitized using a video microscopy system. We aligned the histology and medical images to the reference tissue images using our 3D registration method. We applied the method to correlate in vivo magnetic resonance (MR) and histological measurements for radio-frequency thermal ablation lesions in rabbit thighs. For registration evaluation, we used an ellipsoid model to describe the lesion surfaces. The model surface closely fit the inner (M1) and outer (M2) boundaries of the hyperintense region in MR lesion images, and the boundary of necrosis (H1) in registered histology images. We used the distance between the model surfaces to indicate the 3D registration error. For four experiments, we measured a registration accuracy of 0.96+/- 0.13 mm (mean+/-SD) from the absolute distance between the M2 and H1 model surfaces, which compares favorably to the 0.70 mm in-plane MR voxel dimension. This suggests that our registration method provides sufficient spatial correspondence to correlate 3D medical scanner and histology data.