Spatial resolution (CT)

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Spatial resolution in CT is the ability to distinguish between object or structures that differ in density.

A high spatial resolution is important for one to discriminate between structures that are located within a small proximity to each other.

Factors affecting CT spatial resolution

  • field of view 
    • as the FOV increases so do the pixel size; resulting in a decrease 
  • pixel size
    • the smaller the pixel size the higher the spatial resolution
  • focal spot size
    • a larger focal spot will decrease the resolution 
  • magnification 
    • increasing will decrease the resolution
  • motion of the patient 
  • pitch 
    • is inversely related to the resolution, the higher the pitch the less the resolution 
  • kernel  
    • edge enhancement kernels will have a higher resolution than soft tissue kernels 
  • slice thickness 
    • the larger the slice thickness the lower the resolution
  • detector size 
    • increase in detector size decreases resolution