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Principles of Interpretation. Dr. LeeAnn Pack Dipl. AVCR. It’s Magic. Imagination if more important than knowledge…. Viewing the Radiographs. Quite, dark room, no distractions At least 2 well lit view boxes Hot light should be available 3 dimensional concept
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Principles of Interpretation Dr. LeeAnn Pack Dipl. AVCR
It’s Magic Imagination if more important than knowledge….
Viewing the Radiographs • Quite, dark room, no distractions • At least 2 well lit view boxes • Hot light should be available • 3 dimensional concept • From a 2 dimensional image the 3rd dimension must be constructed • Orthogonal views • Anatomy text, anatomical specimens, notes
Viewing the Radiographs • Radiographs should be placed on the view box the same way every time • Laterals • Animal’s head to the viewer’s left • Spine is at the top • VD or DV • Animal’s head is at the top • Animal’s right is to the viewer’s left
Viewing the Radiographs Limbs • Lateral and Obliques • Proximal is to the top • Cranial or Dorsal is to the viewer’s left • Dorsopalmar / dorsoplantar • Proximal is to the top • Lateral can be to the viewers right or left • I usually place them as if the patient were laying in front of me
The Radiograph • Ensure the image is of the correct patient • Images are correctly labeled • High technical quality – adequate collimation, exposure, development and are free of artifacts • Is it normal, abnormal, artifactual?
Radiographic Opacities • Metal • Mineral – Bone • Soft tissue – fluid • Fat • Air
Evaluating the Radiograph • Take into account the patient history and clinical signs • Does an abnormality exist? • Perception of abnormal • Where exactly is the abnormality? • Describe the roentgen signs • Opinion • Rule out list of prioritized differentials
Roentgen Signs • Size • Shape • Margination • Number • Change in position • Alteration in opacity • Change in function of organs • Roentgen signs should be correlated with history, physical exam, disease patterns, pathogenesis etc.
Other • Summation – same opacity do not touch but are superimposed the opacity where they overlap is increased • Silhouette sign – structures of the same opacity touch and their margins are lost • Contrast Media • GI, GU, neuro etc.
Pitfalls to Interpretation • Do not get distracted by a large mass for example and forget the rest of the radiograph • Tunnel vision • Must use a systematic approach - every time
Summary • Properly displayed, Viewing environment, technical quality • Normal or abnormal – must know anatomy • Systematic evaluation and correlation with clinical data • Correct diagnosis or send to someone for help