title: Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues.
abstract: Morphologists have historically had to rely on destructive procedures to visualize the three-dimensional (3-D) anatomy of animals. More recently, however, non-destructive techniques have come to the forefront. These include X-ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard-tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT-based research is the use of chemical agents to render visible, and differentiate between, soft-tissue structures in X-ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine-based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine-based, contrast-enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting-edge applications of diffusible iodine-based contrast-enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.
authors.affiliation: Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Gignac
authors.affiliation: Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Kley
authors.affiliation: Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Clarke
authors.affiliation: Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Colbert
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, OH, USA.
authors.forename: Ashley C
authors.initials: AC
authors.lastname: Morhardt
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, OH, USA.
authors.forename: Donald
authors.initials: D
authors.lastname: Cerio
authors.affiliation: Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.
authors.forename: Ian N
authors.initials: IN
authors.lastname: Cost
authors.affiliation: Department of Archaeology, University of York and Hull York Medical School, York, UK.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Cox
authors.affiliation: Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Daza
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, OH, USA.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Early
authors.affiliation: The Medical Center for Birds, Oakley, CA, USA.
authors.forename: M Scott
authors.initials: MS
authors.lastname: Echols
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
authors.forename: R Mark
authors.initials: RM
authors.lastname: Henkelman
authors.affiliation: Department of Theoretical Biology, University of Vienna, Vienna, Austria.
authors.forename: A Nele
authors.identifier: 0000-0001-5176-7154
authors.initials: AN
authors.lastname: Herdina
authors.affiliation: Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.
authors.forename: Casey M
authors.initials: CM
authors.lastname: Holliday
authors.affiliation: Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA.
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Mahlow
authors.affiliation: Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, USA.
authors.forename: Samer
authors.initials: S
authors.lastname: Merchant
authors.affiliation: Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Müller
authors.affiliation: Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA.
authors.forename: Courtney P
authors.initials: CP
authors.lastname: Orsbon
authors.affiliation: Department of Biology, Villanova University, Villanova, PA, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Paluh
authors.affiliation: Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA.
authors.forename: Monte L
authors.initials: ML
authors.lastname: Thies
authors.affiliation: Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.|Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA.
authors.forename: Henry P
authors.initials: HP
authors.lastname: Tsai
authors.affiliation: Department of Biomedical Sciences, Ohio University, Athens, OH, USA.
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Witmer
mesh_terms: D000717:Anatomy, Comparative / Q000379:methods*; D000818:Animals; D003287:Contrast Media; D021621:Imaging, Three-Dimensional; D007454:Iodides; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007454:Iodides; C010389:Lugol's solution
keywords: Lugol's iodine; X-ray micro-CT scanning; alcoholic iodine; destaining; radiographic contrast agents; three-dimensional imaging