Modern Imaging Techniques to Reveal Animal Anatomy Figure 5. mCT and CT representations of mammalian and reptilian vasculatures. CT (a, b) and mCT (c) representations of contrast filled vasculature in mammals and reptiles. (a): Ventral view of the whole body vasculature in a domestic pig (Sus scrofa domesticus). (b): Coronary arteriography of a giraffe (Giraffa camelopardalis) heart. (c): Coronary arteries visualised in the heart of a yellow anaconda (Eunectes notaeus). doi:10.1371/journal.pone.0017879.g005 resolution in the order 1000–3000 mm2 [36] and mCT images down to a voxel size of 1–10 mm2. In the present study, mCT was used to reveal minute structures of the rice field eel vasculature (Figure 4a) and coronary architecture of arteries in the yellow anaconda heart (Figure 5c). These delicate structures are prone to collapse and disintegrate during a thorough dissection under the microscope. The same is true for lung tissue in the turtle (Figure 1f) and toad (Figure 4b, c) as well as the gastrointestinal tract in the tarantula (Figure 3c, d). As discussed by Ziegler et al. [37], a challenge us the enormous amount of data generated, and there is a current need for dedicated databases, where data are stored in a standardized fashion. Besides whole animal reproductions, detailed reproduc- tions of specific organs can be derived from segmentation and manual cropping (Figure 3b and 4c). The development in processing algorithms is likely to facilitate automatic segmentation of entire animals based on geometric definitions of vascular, skeletal and organ structures. However, such automatic process requires specialized information about specific anatomical struc- tures of each species of interest in order to delineate anatomical structures. If such laborious step is feasible, we hypothesise that future anatomical visualisations could be processed relatively fast due to the swiftness in modern electronic data processing. An important benefit of performing dissection on a computerised digital model compared to a real specimen is the forgiveness of this technique. A wrong cut does not wreck a whole, possibly rare, specimen. Digitalized catalogues of museum’s type specimens would allow for various investigations of anatomical characters and may increase the accessibility of phenotypical data, exemplified by Ziegler and colleagues [22–24] who include museum specimens in their morphological research on echinoderms, as well as the impressive catalogue of skeletal and especially cranial morphology in the animal kingdom presented by the Digital Morphology library [27]. Visualisations of inflated lungs (Figure 1f, 3a, 3b and 4b, 4c) are examples of structures that would normally collapse during dissection due to the change in intrathoracic pressure, and thus cause a major dissection artefact. However, this is not the case with non-invasive CT, where the thorax is left unopened and no geometric artefacts appear. Traditional dissections remain neces- sary for many purposes, but digital pre-dissection with MRI and CT could improve the planning of the dissection as well as contribute with valuable additional knowledge. In conclusion, given that clinical scanners found in the majority of larger hospitals are fully suitable for these purposes, we References 1. Walter T, Shattuck DW, Baldock R, Bastin ME, Carpenter AE, et al. (2010) Visualization of image data from cells to organisms. Nature Methods Supplement 7: 26–42. 2. 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Supporting Information Movie S1 CT movie of red-eared slider (Trachemys scripta). Initially the animal is turned 360u along its long axis with a slight change in contrast settings halfway, subsequently the plastron is digitally dissected away to reveal internal skeletal architecture. (MP4) Movie S2 Interactive CT movie of African Savannah monitor (Varanus exanthematicus). (Opened in QuickTime Player it is possible to rotate the three dimensional model). (MOV) Movie S3 MRI movie of whiteknee tarantula (Acanthos- curria geniculate). Initially the animal is turned 360u along its long axis, then contrast settings are changed to reveal the contrast agent filled gastrointestinal tract. (MP4) Movie S4 CT movie of the vasculature of a yellow anaconda (Eunectes notaeus). Initially contrast settings are changed slightly to present only vertebrae and contrast agent filled vasculature, followed by a quick survey of the entire snake’s body. 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