Talk:Computed Tomography
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Cite this page: Hill, M.A. (2026, October 5) Embryology Computed Tomography. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Computed_Tomography |
2013
Concentration-dependent specimen shrinkage in iodine-enhanced microCT
J Anat. 2013 Aug;223(2):185-93. doi: 10.1111/joa.12068. Epub 2013 May 30.
Vickerton P, Jarvis J, Jeffery N. Source Department of Musculoskeletal Biology II, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
Abstract
Iodine potassium iodide (I2 KI) solution can be employed as a contrast agent for the visualisation of soft tissue structures in micro-computed tomography studies. This technique provides high resolution images of soft tissue non-destructively but initial studies suggest that the stain can cause substantial specimen shrinkage. The degree of specimen shrinkage, and potential deformation, is an important consideration when using the data for morphological studies. Here we quantify the macroscopic volume changes in mouse skeletal muscle, cardiac muscle and cerebellum as a result of immersion in the common fixatives 10% phosphate-buffered formal saline, 70% ethanol and 3% glutaraldehyde, compared with I2 KI staining solution at concentrations of 2, 6, 10 and 20%. Immersion in the I2 KI solution resulted in dramatic changes of tissue volume, which were far larger than the shrinkage from formalin fixation alone. The degree of macroscopic change was most dependent upon the I2 KI concentration, with severe shrinkage of 70% seen in solutions of 20% I2 KI after 14 days' incubation. When using this technique care needs to be taken to use the lowest concentration that will give adequate contrast to minimise artefacts due to shrinkage. © 2013 Anatomical Society. KEYWORDS: iodine, iodine potassium iodide, microCT, shrinkage, stain
PMID 23721431
2010
Rapid Three-Dimensional Phenotyping of Cardiovascular Development in Mouse Embryos by Micro-CT with Iodine Staining
Degenhardt K, Wright AC, Horng D, Padmanabhan A, Epstein JA. Circ Cardiovasc Imaging. 2010 Feb 27. PMID: 20190279
2009
MicroCT for comparative morphology: simple staining methods allow high-contrast 3D imaging of diverse non-mineralized animal tissues
BMC Physiol. 2009 Jun 22;9:11.
Metscher BD.
Department of Theoretical Biology, Gerd Müller, University of Vienna, Althanstrasse 14, 1090 Austria. brian.metscher@univie.ac.at Abstract BACKGROUND: Comparative, functional, and developmental studies of animal morphology require accurate visualization of three-dimensional structures, but few widely applicable methods exist for non-destructive whole-volume imaging of animal tissues. Quantitative studies in particular require accurately aligned and calibrated volume images of animal structures. X-ray microtomography (microCT) has the potential to produce quantitative 3D images of small biological samples, but its widespread use for non-mineralized tissues has been limited by the low x-ray contrast of soft tissues. Although osmium staining and a few other techniques have been used for contrast enhancement, generally useful methods for microCT imaging for comparative morphology are still lacking.
RESULTS: Several very simple and versatile staining methods are presented for microCT imaging of animal soft tissues, along with advice on tissue fixation and sample preparation. The stains, based on inorganic iodine and phosphotungstic acid, are easier to handle and much less toxic than osmium, and they produce high-contrast x-ray images of a wide variety of soft tissues. The breadth of possible applications is illustrated with a few microCT images of model and non-model animals, including volume and section images of vertebrates, embryos, insects, and other invertebrates. Each image dataset contains x-ray absorbance values for every point in the imaged volume, and objects as small as individual muscle fibers and single blood cells can be resolved in their original locations and orientations within the sample.
CONCLUSION: With very simple contrast staining, microCT imaging can produce quantitative, high-resolution, high-contrast volume images of animal soft tissues, without destroying the specimens and with possibilities of combining with other preparation and imaging methods. Such images are expected to be useful in comparative, developmental, functional, and quantitative studies of morphology.
PMID 19545439
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2717911
http://www.biomedcentral.com/1472-6793/9/11
2008
Guidelines for computed tomography and magnetic resonance imaging use during pregnancy and lactation
Obstet Gynecol. 2008 Aug;112(2 Pt 1):333-40.
Chen MM, Coakley FV, Kaimal A, Laros RK Jr.
Department of Radiology, University of California, San Francisco, School of Medicine, San Francisco, California, USA. Abstract There has been a substantial increase in the use of computed tomography (CT) and magnetic resonance imaging (MRI) in pregnancy and lactation. Among some physicians and patients, however, there are misperceptions regarding risks, safety, and appropriate use of these modalities in pregnancy. We have developed a set of evidence-based guidelines for the use of CT, MRI, and contrast media during pregnancy for selected indications including suspected acute appendicitis, pulmonary embolism, renal colic, trauma, and cephalopelvic disproportion. Ultrasonography is the initial modality of choice for suspected appendicitis, but if the ultrasound examination is negative, MRI or CT can be obtained. Computed tomography should be the initial diagnostic imaging modality for suspected pulmonary embolism. Ultrasonography should be the initial study of choice for suspected renal colic. Ultrasonography can be the initial imaging evaluation for trauma, but CT should be performed if serious injury is suspected. Pelvimetry now is used rarely for suspected cephalopelvic disproportion, but when required, low-dose CT pelvimetry can be performed with minimal risk. Although iodinated contrast seems safe to use in pregnancy, intravenous gadolinium is contraindicated and should be used only when absolutely essential. It seems to be safe to continue breast-feeding immediately after receiving iodinated contrast or gadolinium. Although teratogenesis is not a major concern after exposure to prenatal diagnostic radiation, carcinogenesis is a potential risk. When used appropriately, CT and MRI can be valuable tools in imaging pregnant and lactating women; risks and benefits always should be considered and discussed with patients.
PMID 18669732
From Wiki
Computed Tomography (CT) imaging works through X-rays that are emitted from a focused radiation source that is rotated around the test subject placed in the middle of the CT scanner.[1] The X-ray is attenuated at different rates depending on the density of tissue it is passing through, and is then picked up by sensors on the opposite end of the CT scanner from the emission source. In contrast to traditional 2D X-ray, since the emission source in a CT scanner is rotated around the animal, a series of 2D images can then be combined into 3D structures by the computer.
