Radiology1- Intro

  1. Total opacity=
    object thickness + inherent opacity (air, fat, soft tissue/fluid, mineral, metal)
  2. How can you achieve some depth perception when looking at 2D radiographs?
    • at least 2 orthogonal projections
    • mentally reconstruct depth using 2 views
  3. What is magnifications, and what causes it?
    • enlargement relative to actual size
    • varies with object-film distance; increased distance leads to increased magnification
  4. What is distortion?
    for a magnified image, each bit of information is spread over a larger area, leading to decreased sharpness [therefore, we want the object being imaged as close to the plate as possible...except lungs]
  5. What causes a summation sign?
    • when parts of a patient are in different planes but are superimposed on each other on an image
    • this causes the opacity of both to increase (summed)
  6. What opacity causes a negative summation?
    gas [makes whatever it is summated with have a decreased opacity]
  7. What causes a silhouette sign?
    • two structures of similar opacity touch each other (but do not overlap really) and create a new silhouette
    • may result in the two structures being unrecognizable
  8. How do you name radiographic projections?
    point of entrance --> point of exit [ex. ventro-dorsal, animal in dorsal recumbency]
  9. How do you hand the different projections (by convention)?
    • Lateral: head to left, spine at top
    • VD/ DV: head at top, patients right on left side of image
    • Craniocaudal/ dorsopalmar: proximal at top, lateral on left side of image
  10. What is radiographic TPR?
    • Technique
    • Positioning
    • phase of Respiration
  11. What are the Rontgen signs? (6)
    • size
    • shape
    • number
    • location
    • margination
    • opacity
Card Set
Radiology1- Intro
vetmed radiology1