Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e
|Section 27. Principles of Imaging >|
Chapter e299.2. Computed Tomography
Sections: Computed Tomography: Introduction, CT versus MRI, Basic Physics and Terminology, Electron Beam Tomography, Helical CT, Multidetector Array CT Scanners, Use of Contrast Agents, Overview of Diagnostic Use of CT, Radiation, Pregnancy and Radiation, References.
Topics Discussed: computed tomography.
Excerpt:"CT is a technique that creates cross-sectional images with the
use of x-rays and computerized image reconstruction. A large series
of two-dimensional x-ray images are taken around a single axis of
rotation as the patient passes through a gantry. The gantry contains
one or more x-ray tubes on one side and an array of detectors on
the other side. As the gantry rotates around the patient, obtained
information from the detectors is analyzed by computer and displayed
as an image. The image information can be manipulated by the computer
to display a greater spectrum of densities than can be displayed
on conventional x-ray film. These images can be manipulated, or "windowed," to
display various tissue densities based on their ability to block
the x-ray beam. Initially, images were limited to the axial plane,
but modern scanners allow reconstruction of the images into both multiple
planes as well as three-dimensional (3D) (volumetric) depiction of
the structures. It is due to this ability to display images in multiple
planes that the term computed axial tomography has
fallen out of favor...."
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