Fig. 3.

Image-guided specimen slicing process. The first step is to select a desired slicing plane orientation and location from the 3D in vivo image. By using image-based registration, this plane is transformed to the space of the ex vivo specimen image. Corresponding fiducial markers are localized on the ex vivo image (by using software) and on the physical specimen (by using a tracked stylus), and a landmark transform aligning these fiducial markers transforms the slicing plane into the space of the tracker. The tracked stylus is used to direct the insertion of three slicing plane–defining pins into the specimen, which align the specimen in a slotted forceps for slicing. This permits the establishment of a correspondence between stained histologic slices and in vivo imaging planes, which are registered by using a non-rigid registration. Reproduced from (Ward et al., 2012).