Equine Foot Radiography

Question 1

What are some indications for radiography of the foot?

Answer 1

• Investigation/evaluation of foot
  
  • Lameness/pathology localised to the foot or pastern
  • Penetrating injuries
  • Chronic infection/discharge
  • Evaluation and monitoring of laminitis (pedal rotation/sinking)
  • Assessment of foot balance (farriery)
  • Monitoring any treatment and/or corrections
• Pre-purchase/insurance examinations

Question 2

What are some radiation safety points?

Answer 2

• Barrier protection
• Plate holder/ stand
• X-ray machine stand
• Dosimeter
• Appropriate positioning and collimation
• Minimal number of views
  
  • Preparation (shoes, packing, markers, positioning etc.)

Question 3

What are some ways you can restrain a horse for radiography?

Answer 3

• Sedation
  
  • With what? (?issues with ataxia and need to lift legs!)
• Handler
  
  • Need to think about handler safety/position and exposure/location
  • –>18, not pregnant/trying to conceive
• Blocks/tunnels for feet
  
  • Blocks: approximately 10cm to allow centering of beam at coronary band
  • Tunnel: non-slip (plate slides inside block to protect it )

Question 4

What are some standard foot views?

Answer 4

• Lateromedial
• Dorsopalmar
• Two dorsoproximal palmarodistal 60°oblique (D60Pr-PaDi oblique) views (Tunnel)
  
  • Pedal
  • Navicular
  • OR use upright pedal technique
• Palmaroproximal palmarodistal 45°oblique (Pa45Pr-PaDi oblique) view
• ?obliques

Question 5

What does mA and kV mean?

Answer 5

• mA
  
  • Number of x-rays fired
• kV
  
  • Energy/ power of x-rays

Question 6

What is film focal distance?

Answer 6

• Film focal (FF) distance- distance from X-ray head (not collimation chamber) to plate

(make sure you know what your machine FF distance is!)

Question 7

Explain how you should perform a latero-medial view of the foot?

Answer 7

• Horse should be fully weight-bearing
• Try and get horse stood square, NOT toe in or toe out.
• Centre on coronet band midway dorsal-palmar
• Align beam parallel to heel bulbs (use cane)
• FF distance, collimation, horizontal beam
• Marker dorsally on plate
• ?Dorsal hoof/frog marker

Question 8

Explain how you should perform a dorsopalmar view of the foot?

Answer 8

• Weightbearing
• Horizontal beam
• Center on coronet band , midway medial- lateral
• FF distance, collimation, ensure horizontal beam!

Question 9

Explain how you should perform an upright Pedal/D60Pr-PaDi oblique Projections view of the foot?

Answer 9

• Upright pedal gold standard but need/expose extra person…
• DPr60PaDiO view less people, but image distortion
• Both: Center on coronet band
• Tunnel- foot weightbearing towards front, X-ray beam angled down 60 degrees.
• Upright pedal – foot held on toe, sole perpendicular to floor, plate behind, horizontal beam
• Pack sulci to avoid air artefact!

Question 10

Explain how you should perform an upright Navicular/D60Pr-PaDi oblique Projections of the foot?

Answer 10

• Same approach as for pedal bone views
  
  • If upright in block, tip foot over slightly so dorsal hoof wall about 85 degrees from horizontal
  • Tunnel as for P3 view
• Centre 1-2 cm above the coronary band
• Collimate right down
• Pack!

Question 11

Explain how you should perform a flexor Navicular (Pa45Pr-PaDi oblique) Projection of the foot?

Answer 11

• Foot on tunnel
  
  • Foot caudal on block
  • Access: Toe in/ block out
• Not always at 45°
  
  • steepest angle possible without hitting back of fetlock
• Centre between heel bulbs
• Collimate, FF distance
• May have to decrease exposure if FF distance reduced to get under belly…
• For safety try and sort FF distance, angle and collimation away from horse beforehand

Question 12

What does a DLPMO highlight?

Answer 12

highlights dorsomedial and palmarolateral aspect

Question 13

What does a DMPLO highlight?

Answer 13

highlights dorsolateral and palmaromedial aspect