Oriented sectioning of irregular tissue blocks in relation to computerizedscanning modalities: Results from the domestic pig brain

We present a new method allowing direct comparison between images obtained by present digital scanning modalities and histological sections from the s ame object. More specifically the paper illustrates how to orientate, embed , and section large irregular tissue blocks after magnetic resonance imagin g (MRI) in such a way that accurate correlation of the digital data sets to histological sections is possible. The functionality and capability of the described procedure and slicing machine is illustrated by results from the pig brain. Accordingly, three pigs were MR-scanned, followed by perfusion fixation. The brains were removed, oriented according to the MR scans, embe dded in alginate, and cut on a newly developed slicing machine. The tissue blocks were then stained to reveal grey and white matter and photographed b efore final sectioning on a cryostat into 80 mum thick sections which were Niss1-stained with toluidine. The results demonstrate how our method enable s direct comparison between the pig brain MR images and the later obtained histological sections. The alginate embedding method and slicing machine of fer the same possibilities for other parenchymateous organs and soft tissue s and may, in addition, be of use in stereological analysis. (C) 2000 Elsev ier Science B.V. All rights reserved.