computerized tomography (CT)

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* pacemaker, implantable cardioverter defibrillator


  • CT images are obtained by computed reconstruction from measurements of differential X-ray absorbtion obtained through an angle of 360 degrees.
  • these measurements obtained by electronic detection allow calculation of radiographic densities at any point in plane represented as pixels in the CT software
  • radiographic densities are measured in Hounsfield units
  • conventional CT examines 8-10 mm slices obtained at 10 mm intervals
  • high-resolution CT (HRCT) examines 1-2 mm slices & delineates detail that convention CT does not
  • helical or spiral CT allows 3-dimensional data acquistion & reduces motion artifact
  • contrast is generally used to identify vasculature or the gastrointestinal tract
  • Naeotom Alpha CT utilizes photon-counting detectors that can count individual x-ray photons that pass through a patient & discriminate their energy[18]


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