Radiology diagnosis errors due to artifacts

1. Presented by
Dr Ajith Y. MVSc
Division of Medicine
IVRI, Izatnagar, UP, India

2. Any appearance/opacity on a radiograph
which doesn’t represents an actual anatomic
structure within the patient being
radiographed.

4. • Degrades quality of radiograph and affect
interpretation.
- Cause visual distractions for the radiologist
leading to misrepresentation of an actual
anatomic structure
- Can mimic pathology
• Render a radiographic study non-diagnostic

5. Post
exposure
Exposure
Pre
exposure

6. A. Pre exposure artifacts (Film storage and Handling)
Pressure
Abrasions & Scratches
Fingerprints
Static electricity
Material in cassette
Light leak

7. • Pressure
- Black Crescents Marks
- Due to rough handling and bending of film.

8. • Abrasions & Scratches
- Black: pressure from abrasion activates crystals
- White: emulsion has been removed (scratch)
- Due to rough handling

9. • Fingerprints
- Black: Developer on fingertips
- White: Oil or Fixer on fingertips blocks developer
- Keep fingers dry and clean
- Touch only film edges

10. • Static electricity (ARBORESCENT STREAK)
- Two patterns: Branching and Smudge / spot
- Cause: Static electricity by friction/ due to low humidity
- Avoid friction and provide moderate humidity

11. • Material in cassette
- X rays are prevented from
reaching film
- Common cause: Hair; dust

12. • Light leak
- A form of fog
- Cassette not closed properly
- Safelight filter crack

13. B. Positioning
• Magnification
• Foreshortening / distortion
• Patient rotation
• Upside-down cassette
• Grid cut off

14. • Magnification
• Object closer to film:
– Closer to normal size
– Sharper margins
• Object far from film:
– Magnified
– Less distinct margins

15. • Foreshortening / distortion
- X-ray beam does not pass
perpendicular to long axis
of structure
- Differential magnification of
structure
Unequal
magnification

16. • Patient rotation
- A form of distortion.
- Lesions may be masked by
atypical superimposition on
normal anatomy.
Summation shadow of penis over caudal lumber vertebras

17. • Upside-down cassette
- White & focal: Springs & latches on back of cassette
block x-ray beam
- Global lightness: Lead backing absorbs some x-rays
(film appears underexposed)

18. • Grid cut off
- Grid is not aligned with beam
- Loss of primary radiation as a
result of undesirable absorption.
- Too light and less contrast image

19. • Grid cut off

20. C. Exposure artifacts
• Motion
• Double exposure
• Overexposure
• Underexposure
• Material obstructing x-ray beam

21. • Motion
- Blurred image
- Poor clarity
- Less sharp edges
- Non-sedated animal
- Panting
- Prevention
Sedation
Restrain
Stable Cassette
Stable X ray unit

22. • Double exposure
- Film is darker than a single exposure
- Same image: Double click
- Two separate image: Already exposed film

23. • Over exposure
- Too high mAs or kVp
- Body size low
- Decreased FFD
- Over development

24. • Under exposure
- Too low mAs or kVp
- Body size high
- Increased FFD
- Under development
- Two films in cassette

25. • Material obstructing x-ray beam
- Radiopaque structure
- Dust particles
- On or in patient
- Above cassette

26. D. Post exposure artifacts (Film processing)
 Overdevelopment
 Underdevelopment
 Insufficient mixing
 Incomplete fixation
 Incomplete washing
 Frosty area on film
 Finger marks
 Dark line on top
 White line on top
 Blank film
 Chemical fog

27. • Overdevelopment
- Black & global
- Cause: Too much metallic
Ag forms in emulsion
- Developer too hot
- Developed too long

28. • Underdevelopment
- White & global
- Cause: Too little metallic
Ag forms in emulsion
- Developer too cold
- Developed too little time

29. • Uneven development
• Chemical levels are uneven: affect developing and fixing
• Top of the film.
- White horizontal area on top of the film
- Dark horizontal area on top of the film
• If the chemicals are not stirred prior to use.

30. • Unevenly developed
Uneven Chemical Levels
not exposed, is developed,
and not fixed
exposed, developed, and
fixed
not exposed, developed,
and partially fixed
not exposed, but is
developed and fixed

31. • Insufficient mixing
- White streaky appearance
over the entire film.

32. • Incomplete fixation
- Initially film is cloudy and milky
- Over time appears yellow/brown –Dichroic stain
-

33. • Incomplete washing
- Fixer remains
– Cloudy, sticky residue
– Yellow-brown stain
– Sulfur smell

34. • Fog
-Increased blackness
- Regional or global
- Definition: any
unwanted film
exposure /development
- Decreased image
contrast and detail

35. • Fog: causes
- Excessive pressure
- Heat- film should be stored at <68 F
- Light- from outside source or safelight
- Humidity- should be 30-50%
- Chemical- over developing
- Old film
- Certain gases
- Scatter radiation

36. E. Artifacts in Digital/Computerised radiography
• Cassette Debris
• Faulty Transfer
• Uberschwinger or rebound effect

37. • Faulty transfer
- Distorted appearance
- Problems in data transfer

38. • Uberschwinger or rebound effect.
• Black lines occur around dense structure border
– Can be mistaken for loosening or infection of
implants
• Cause: Certain processing algorithms (edge
enhancement)

39. • Uberschwinger or rebound effect.