Modern Imaging Techniques to Reveal Animal Anatomy Figure 3. CT and MRI of organ structures. CT (a, b) and MRI (c, d) representations of organ structures. (a): Ventral view of American alligator (Alligator mississippiensis) with lungs (gray), liver (yellow) and heart (red) highlighted. (b): Ventrolateral view of American alligator (Alligator mississippiensis) with air-filled structures (lungs and trachea) highlighted blue. (c) and (d): Coronal (c) and lateral (d) view of whiteknee tarantula (Acanthoscurria geniculate) with the gastrointestinal tract enhanced following ingestion of MRI contrast agent. doi:10.1371/journal.pone.0017879.g003 PLoS ONE | www.plosone.org 6 March 2011 | Volume 6 | Issue 3 | e17879