title: Rapid 3D phenotyping of cardiovascular development in mouse embryos by micro-CT with iodine staining.
abstract: BACKGROUND
  Microcomputed tomography (micro-CT) has been used extensively in research to generate high-resolution 3D images of calcified tissues in small animals nondestructively. It has been especially useful for the characterization of skeletal mutations but limited in its utility for the analysis of soft tissue such as the cardiovascular system. Visualization of the cardiovascular system has been largely restricted to structures that can be filled with radiopaque intravascular contrast agents in adult animals. Recent ex vivo studies using osmium tetroxide, iodinated contrast agents, inorganic iodine, and phosphotungstic acid have demonstrated the ability to stain soft tissues differentially, allowing for high intertissue contrast in micro-CT images. In the present study, we demonstrate the application of this technology for visualization of cardiovascular structures in developing mouse embryos using Lugol solution (aqueous potassium iodide plus iodine).
  
  
  RESULTS
  We show the optimization of this method to obtain ex vivo micro-CT images of embryonic and neonatal mice with excellent soft-tissue contrast. We demonstrate the utility of this method to visualize key structures during cardiovascular development at various stages of embryogenesis. Our method benefits from the ease of sample preparation, low toxicity, and low cost. Furthermore, we show how multiple cardiac defects can be demonstrated by micro-CT in a single specimen with a known genetic lesion. Indeed, a previously undescribed cardiac venous abnormality is revealed in a PlexinD1 mutant mouse.
  
  
  CONCLUSIONS
  Micro-CT of iodine-stained tissue is a valuable technique for the characterization of cardiovascular development and defects in mouse models of congenital heart disease.
authors.affiliation: Department of Cell and Developmental Biology, Penn Cardiovascular Institute, University of Pennsylvania, Philadelphia, PA 19104, USA. degenhardt@email.chop.edu
authors.forename: Karl
authors.initials: K
authors.lastname: Degenhardt
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Wright
authors.forename: Debra
authors.initials: D
authors.lastname: Horng
authors.forename: Arun
authors.initials: A
authors.lastname: Padmanabhan
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Epstein
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002319:Cardiovascular System / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000196:embryology*; D004396:Coloring Agents; D004195:Disease Models, Animal; D006321:Heart / Q000000981:diagnostic imaging; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging* / Q000196:embryology; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007454:Iodides; D051379:Mice; D010641:Phenotype; D011856:Radiographic Image Enhancement / Q000379:methods; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D004396:Coloring Agents; D007454:Iodides; C010389:Lugol's solution