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1.
Dev Dyn ; 245(10): 1001-10, 2016 10.
Article in English | MEDLINE | ID: mdl-27447729

ABSTRACT

BACKGROUND: Gestationally survivable congenital malformations arise during mid-late stages of development that are inaccessible in vivo with traditional optical imaging for assessing long-term abnormal patterning. MicroCT is an attractive technology to rapidly and inexpensively generate quantitative three-dimensional (3D) datasets but requires exogenous contrast media. Here we establish dose-dependent toxicity, persistence, and biodistribution of three different metallic nanoparticles in day 4 chick embryos. RESULTS: We determined that 110-nm alkaline earth metal particles were nontoxic and persisted in the chick embryo for up to 24 hr postinjection with contrast enhancement levels at high as 1,600 Hounsfield units (HU). The 15-nm gold nanoparticles persisted with x-ray attenuation higher than that of the surrounding yolk and albumen for up to 8 hr postinjection, while 1.9-nm particles resulted in lethality by 8 hr. We identified spatial and temporally heterogeneous contrast enhancement ranging from 250 to 1,600 HU. With the most optimal 110-nm alkaline earth metal particles, we quantified an exponential increase in the tissue perfusion vs. distance from the dorsal aorta into the flank over 8 hr with a peak perfusion rate of 0.7 µm(2) /s measured at a distance of 0.3 mm. CONCLUSIONS: These results demonstrate the safety, efficacy, and opportunity of nanoparticle based contrast media in live embryos for quantitative analysis of embryogenesis. Developmental Dynamics 245:1001-1010, 2016. © 2016 Wiley Periodicals, Inc.


Subject(s)
Contrast Media/adverse effects , Metal Nanoparticles/adverse effects , X-Ray Microtomography/methods , Animals , Chick Embryo , Contrast Media/chemistry , Embryonic Development/physiology , Metal Nanoparticles/chemistry
2.
Methods Mol Biol ; 1189: 47-61, 2015.
Article in English | MEDLINE | ID: mdl-25245686

ABSTRACT

Tissue morphogenesis and embryonic development are dynamic events challenging to quantify, especially considering the intricate events that happen simultaneously in different locations and time. Micro- and more recently nano-computed tomography (micro/nanoCT) has been used for the past 15 years to characterize large 3D fields of tortuous geometries at high spatial resolution. We and others have advanced micro/nanoCT imaging strategies for quantifying tissue- and organ-level fate changes throughout morphogenesis. Exogenous soft tissue contrast media enables visualization of vascular lumens and tissues via extravasation. Furthermore, the emergence of antigen-specific tissue contrast enables direct quantitative visualization of protein and mRNA expression. Micro-CT X-ray doses appear to be non-embryotoxic, enabling longitudinal imaging studies in live embryos. In this chapter we present established soft tissue contrast protocols for obtaining high-quality micro/nanoCT images and the image processing techniques useful for quantifying anatomical and physiological information from the data sets.


Subject(s)
Imaging, Three-Dimensional , Morphogenesis , Nanotechnology/methods , X-Ray Microtomography/methods , Animals , Antigens/metabolism , Contrast Media , Embryo, Mammalian/diagnostic imaging , Mice , Microinjections
3.
Birth Defects Res C Embryo Today ; 99(2): 106-20, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23897595

ABSTRACT

Congenital heart defects (CHD) are the most prevalent congenital disease, with 45% of deaths resulting from a congenital defect due to a cardiac malformation. Clinically significant CHD permit survival upon birth, but may become immediately life threatening. Advances in surgical intervention have significantly reduced perinatal mortality, but the outcome for many malformations is bleak. Furthermore, patients living while tolerating a CHD often acquire additional complications due to the long-term systemic blood flow changes caused by even subtle anatomical abnormalities. Accurate diagnosis of defects during fetal development is critical for interventional planning and improving patient outcomes. Advances in quantitative, multidimensional imaging are necessary to uncover the basic scientific and clinically relevant morphogenetic changes and associated hemodynamic consequences influencing normal and abnormal heart development. Ultrasound is the most widely used clinical imaging technology for assessing fetal cardiac development. Ultrasound-based fetal assessment modalities include motion mode (M-mode), two dimensional (2D), and 3D/4D imaging. These datasets can be combined with computational fluid dynamics analysis to yield quantitative, volumetric, and physiological data. Additional imaging modalities, however, are available to study basic mechanisms of cardiogenesis, including optical coherence tomography, microcomputed tomography, and magnetic resonance imaging. Each imaging technology has its advantages and disadvantages regarding resolution, depth of penetration, soft tissue contrast considerations, and cost. In this review, we analyze the current clinical and scientific imaging technologies, research studies utilizing them, and appropriate animal models reflecting clinically relevant cardiogenesis and cardiac malformations. We conclude with discussing the translational impact and future opportunities for cardiovascular development imaging research.


Subject(s)
Heart/diagnostic imaging , Heart/embryology , Image Processing, Computer-Assisted/methods , Animals , Diagnostic Imaging/methods , Disease Models, Animal , Fetal Diseases/diagnosis , Fetal Diseases/diagnostic imaging , Fetal Diseases/mortality , Heart Defects, Congenital/diagnosis , Heart Defects, Congenital/diagnostic imaging , Heart Defects, Congenital/mortality , Humans , Magnetic Resonance Imaging/methods , Radiography , Ultrasonography
4.
Differentiation ; 84(1): 149-62, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22695188

ABSTRACT

Animal models are critically important for a mechanistic understanding of embryonic morphogenesis. For decades, visualizing these rapid and complex multidimensional events has relied on projection images and thin section reconstructions. While much insight has been gained, fixed tissue specimens offer limited information on dynamic processes that are essential for tissue assembly and organ patterning. Quantitative imaging is required to unlock the important basic science and clinically relevant secrets that remain hidden. Recent advances in live imaging technology have enabled quantitative longitudinal analysis of embryonic morphogenesis at multiple length and time scales. Four different imaging modalities are currently being used to monitor embryonic morphogenesis: optical, ultrasound, magnetic resonance imaging (MRI), and micro-computed tomography (micro-CT). Each has its advantages and limitations with respect to spatial resolution, depth of field, scanning speed, and tissue contrast. In addition, new processing tools have been developed to enhance live imaging capabilities. In this review, we analyze each type of imaging source and its use in quantitative study of embryonic morphogenesis in small animal models. We describe the physics behind their function, identify some examples in which the modality has revealed new quantitative insights, and then conclude with a discussion of new research directions with live imaging.


Subject(s)
Embryonic Development , Animals , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Mice , Microscopy, Acoustic , Microscopy, Confocal , Microscopy, Fluorescence , Models, Animal , Ultrasonography, Doppler , X-Ray Microtomography
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