Artefakte im Röntgenbild

X-ray artifacts can present in a variety of ways including abnormal shadows noted on a radiograph or degraded image quality, and have been produced by artificial means from hardware failure, operator error and software (post-processing) artifacts.

There are common and distinct artifacts for film, computed (CR) and digital radiography (DR).

Common causes

  • improper handling of the films
  • errors while processing the films
  • patient movement while taking the image

Common artifacts (all forms of radiography)

  • motion artifact
    • due to patient movement resulting in a distorted image
  • image compositing (or twin/double exposure)
    • superimposition of two structures from different locations due to double exposure of same film/plate
  • grid cut-off
  • radiopaque objects on/external to the patient (e.g. jewelry (e.g. necklaces, piercings), clothing (e.g. buttons), hair (e.g. ponytail, hair braids etc.).
  • debris in the housing 
    • debris in the housing caused by the collimator tube can cause small trapezoidal regions, indicative of lead shavings 

Film radiography artifacts

  • finger marks
    • improper handling with hands
  • clear film
    • malfunction of the machine or placing the film in the fixer before developer solution
  • static electricity
    • black “lightning” marks resulting from films forcibly unwrapped or excessive flexing of the film
  • crescent-shaped black lines
    • due to fingernail pressure on the film
  • crescent-shaped white lines
    • due to cracked intensifying screen
  • black film
    • complete exposure to light.
  • clear spots
    • air bubbles sticking to film during processing
    • fixer splashed on film prior to developing
    • dirt on the intensifying screen

Computed/digital radiography artifacts

  • detector image lag or ghosting
    • latent image from previous exposure present on current exposure
  • incorrect detector orientation i.e. upside-down cassette
    • spoke like radiopaque lines (case 6)
  • backscatter
    • electronics are visible on the exposed image
    • increased radiation exposure required for portable DR (digital radiography) examinations
  • stitching artifacts
    • occur when two separate DR or CR (computed radiography) images are merged into a single image (see case 3)
  • over exposure
  • dead pixel artifact
  • signal dropout
    • large areas of signal loss, due to detector drop
  • speckled radiopaque spots
    • due to detector drop
  • detector calibration limitation
    • faint radioopaque striping (often vertical) in the background of an image, yet not evident on the anatomy 
    • this artifact should be carefully examined, if it does not interfere with the anatomy, it is not a detector failure/grid cut off, rather a limitation of the detector calibration. 
    • often seen as lower exposure
  • failure of detector offset correction
    • similar to ghosting, however, the digital detector not being calibrated when promoted is the cause 
  • electronic shutter failure
    • the digital image often will have obscurely shaped, tight collimation that defies logic
    • often a computer error often fixed with recollimation post exam (this should be explored before reexamination)
  • values of interest misread
    • image appears washed out and underexposed
    • this is often due to a largely collimated area of smaller anatomy i.e. a patella protection 
    • tighter digital collimation in conjunction with reprocessing will correctly assign the correct values of interest
  • mid grey clipping
    • loss of contrast in areas of different pixel density yet not change in density can be seen i.e. the metal on a knee replacement 
    • due to poor contrast enhancement
  • grid-line suppression failure
    • faint grid lines present on an image, with no grid cut off
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