This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Radiographic films are widely used in the veterinary profession as an aid to diagnosis, but a disciplined approach to reading them is rarely applied outside referral centres and practices with a member of staff holding a post-graduate qualification in the subject.

It has been estimated that 80% of errors in radiology are due to a failure by the film reader to observe a visible lesion. For example, in trauma cases clinicians relatively easily recognize and document the obvious bone lesions, but they may fail to identify and record associated soft-tissue lesions.

There are certain procedures that can be used to help to avoid errors in film reading :

• Always take radiographs of the anatomical site being investigated in at least two projections (at 90^o to each other)
• Make sure that the radiographs that you have taken are of diagnostic quality. Change the radiographic exposure and repeat them if necessary to get good films
• If you are not sure about your findings - compare the image(s) with known normal and abnormals - in your own reference library of images, or in a reputable textbook. 
• If you are examining a single limb and you are not sure whether a finding is abnormal or not, take a similar radiograph of the other limb for comparison. 
• Remember that the XRay film is a photographic image and try to interpret it in two stages :
  • Describe what you can see on the image - radiographic description
  • Interpret your photographic description - radiological interpretation
• Always look at everything on the image
• Develop a routine approach to reading films and stick to it. For example - abdominal radiographs can be interpreted in several ways :
  • an organ system approach - eg start with the alimentary tract, then the urogenital tract and so on; or 
  • a sector approach - eg divide the abdomen into 6 sectors and examine the lower cranial compartment first, then the upper cranial compartment, then the lower mid-abdomen , and so on.
  • a radiographic-density approach - identify and describe the most radiodense (white) areas (usually bone) on the image, then work through shades of grey until you get to the most radiolucent (black) areas (usually gas)
• Don't let your eyes rush to an obvious lesion (e.g. a fractured bone) - force yourself to interpret the whole radiographic image in a systematic way...you are much less likely to miss something, and you are most likely to recognize some secondary lesion of importance.
• For each identifiable anatomical structure ask the following questions :
  • Has it normal/abnormal radiodensity ?
  • Is it in a normal/abnormal location in the body ?
  • Does it have a normal anatomical relationship with neighbouring structures?
  • Has it a normal/abnormal contour (outline) - e.g. rough/smooth ?
  • Does it have a normal/abnormal shape
  • Is it normal/abnormal in size (increased/decreased) ?
  • Is there any other abnormal radiographic finding. e.g. is an expected finding absent?

• Describe and document all abnormal findings in detail.
• Sometimes the hardest thing to do is to say that a radiographic feature is NORMAL. 
• Try to read radiographic films without referring to the case history. In veterinary film reading sessions there have been many instances when a radiographer has picked up a radiographic finding by reading a film blind, and this has subsequently redirected the primary clinicians investigations towards an accurate diagnosis. 

Practice Tip 1

Form your own radiographic library of normal and abnormal films to compare with radiographic films from difficult cases.

Practice Tip 2

Try to get all the clinicians in your practice together for 30mins-1 hour at least once a week to re-read the radiographic films that the practice have taken. Encourage each other to question the diagnosis and to identify missed radiographic findings. 

Last updated : January 2016