title: In ovo monitoring of smooth muscle fiber development in the chick embryo: diffusion tensor imaging with histologic correlation.
abstract: BACKGROUND
  Magnetic resonance imaging is a noninvasive method of evaluating embryonic development. Magnetic resonance diffusion tensor imaging, which is based on the measuring the directional diffusivity of water molecules, is an established method of evaluating tissue structure. Prolonged imaging times have precluded the use of embryonic diffusion tensor imaging due to motion artifact. Using temperature-based motion suppression, we aimed to investigate whether diffusion tensor imaging can be used to monitor embryonic smooth muscle development in ovo, and to determine the correlation between histologically-derived muscle fiber fraction, day of incubation and diffusion tensor imaging fractional anisotropy values and length of tracked fibers.
  
  
  RESULTS
  From a set of 82 normally developing fertile chicken eggs, 5 eggs were randomly chosen each day from incubation days 5 to 18 and cooled using a dual-cooling technique prior to and during magnetic resonance imaging at 3.0 Tesla. Smooth muscle fibers of the gizzard were tracked using region of interests placed over the gizzard. Following imaging, the egg was cracked and the embryo was fixated and sectioned, and a micrograph most closely corresponding to the acquired magnetic resonance image was made. Smooth muscle fiber fraction was determined using an automated computer algorithm.
  
  
  CONCLUSIONS
  We show that diffusion tensor images of smooth muscle within the embryonic gizzard can be acquired in ovo from incubation day 11 through hatching. Length of tracked fibers and day of incubation were found to have statistical significance (p<0.05) by multiple linear regression correlation with histologic specimens of sacrificed embryos from day 11 of incubation through hatching. The morphologic pattern of development in our histologic specimens corresponds to the development of embryonic gizzard as reported in the literature. These results suggest that diffusion tensor imaging can provide a noninvasive method of evaluating in ovo development of smooth muscle tissue.
authors.affiliation: Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Xu
authors.forename: Zachary
authors.initials: Z
authors.lastname: Delproposto
authors.forename: Zien
authors.initials: Z
authors.lastname: Zhou
authors.forename: Huicong
authors.initials: H
authors.lastname: Shen
authors.forename: Stephanie Yang
authors.initials: SY
authors.lastname: Xuan
authors.forename: Qing Hang
authors.initials: QH
authors.lastname: Li
authors.forename: E Mark
authors.initials: EM
authors.lastname: Haacke
authors.forename: Jiani
authors.initials: J
authors.lastname: Hu
mesh_terms: D000818:Animals; D002642:Chick Embryo; D004058:Diffusion; D009130:Muscle, Smooth / Q000196:embryology*