title: In utero localized diffusion MRI of the embryonic mouse brain microstructure and injury.
abstract: OBJECTIVE
  To develop an in vivo diffusion magnetic resonance imaging (dMRI) technique to study embryonic mouse brain structure and injury.
  
  
  METHODS
  Pregnant CD-1 mice were examined on embryonic day 17 on an 11.7T scanner. Spatially selective excitation pulses were used to achieve localized imaging of individual mouse brains, in combination with a 3D fast imaging sequence to acquire dMRI at 0.16-0.2 mm isotropic resolution. Subject motions were corrected by navigator echoes and image registration. Further acceleration was achieved by simultaneous imaging of two embryos in an interleaved fashion. We applied this technique to detect embryonic brain injury in a mouse model of intrauterine inflammation.
  
  
  RESULTS
  With the localized imaging technique, we achieved in utero high-resolution T2 -weighted and dMRI of the embryonic mouse brain for the first time. Early embryonic brain structures were delineated from diffusion tensor images, and major white matter tracts were reconstructed in 3D. Comparison with ex vivo data showed significant changes in the apparent diffusion coefficient (ADC), but mostly unchanged fractional anisotropy. In the inflammation-affected embryonic brains, ADC in the cortical regions was reduced at 6 hours after the injury, potentially caused by cellular edema.
  
  
  CONCLUSIONS
  The feasibility of in utero dMRI of embryonic mouse brains was demonstrated. The technique is important for noninvasive monitoring of embryonic mouse brain microstructure and injury.
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.affiliation: Integrated Research Center for Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Lei
authors.affiliation: Integrated Research Center for Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Rosenzweig
authors.affiliation: Integrated Research Center for Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Burd
authors.affiliation: Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Jiangyang
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D016880:Anisotropy; D001921:Brain / Q000196:embryology* / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007249:Inflammation; D008070:Lipopolysaccharides / Q000737:chemistry; D051379:Mice; D015233:Models, Statistical; D009038:Motion; D011247:Pregnancy; D011270:Pregnancy, Animal; D059629:Signal-To-Noise Ratio; D013382:Subtraction Technique
chemical_list: D008070:Lipopolysaccharides
keywords: MRI; in utero; localized diffusion; microstructure