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Top Tips for Taking Perfect Veterinary Radiographs

Posted in Operations @ Apr 27th 2017 - By Zoe Lenard & Nola Lester, Veterinary Imaging Centre
Perfect Radiographs Dogs Head Ct

Obtaining perfect, diagnostic radiographs in veterinary practice can seem daunting.

Updated April 2017

However just follow this simple checklist to help you get the most out of this modality. Once you have great radiographs, you are more likely to get helpful information. Radiography remains a simple and highly effective diagnostic tool, and obtaining radiographs should be quicker than waiting for your blood samples to be analysed in-house.

Sedation is really helpful. Routinely lightly sedating dogs and cats for radiographic procedures (particularly abdomen and thorax) will vastly improve the quality of your study. Fractures, painful musculoskeletal imaging (e.g. cruciate ruptures) and spinal imaging may require a GA.  

  • Butorphanol 0.3mg/kg + ACP 0.01mg/kg IM/SC
  • For IV doses: reduce to butorphanol 0.2mg/kg & ACP to 0.005mg/kg
  • For cardiac, renal, hepatic disease: reduce to butorphanol 0.1mg/kg  +/- ACP 0.005mg/kg (or avoid ACP)

Table top exposures: extremities, anything less than 10-12cm thick (cats, small dog thoraxes). Even in digital systems, you will have better detail with tabletop technique, so consider this for any extremity.

Grid/Bucky exposures: anything > 10-12cm thick (medium to large dogs) for CR and film. DR doesn’t need a grid.

Collimation: make sure you can see all 4 edges on your plate for medium and large dog thoraxes and abdomens. For ANY table top exposure open up your collimation to expose at least 30% of the plate.

Positioning for Thorax and Abdomen

1.       Sedated patient

2.       Abdomen: fasting is generally required for elective imaging

3.       Two orthogonal views required always (R lateral and VD)

  • Lung disease: three views (R and L lateral and VD, or DV) may be required
  • GDV: R lateral projection may be all that is required

4.       Lateral projection: palpate spine and sternum so they are equidistant off the table

  • Costochondral junctions level (thorax) 
  • Transverse processes of spine superimposed (abdomen).

5.       VD projection = sternum and spine superimposed, pelvis is symmetrical

6.       Collimate

  • THORAX: Centre on caudal boarder of scapula. Collimate from the thoracic inlet to the junction of the 13th rib and spine.
  • ABDOMEN: centre on umbilicus. Collimate from junction of ribs with spine to greater trochanter of femur.

7.       Rotation makes studies un-interpretable

Positioning for head and neck

1.       GA generally required, else rotation will occur

2.       Lateral: position the thorax for a lateral projection. Place a small sponge or towel under the mid neck to stop droop. Ensure the nose is elevated off the table to be level with the sagittal crest of the skull.

3.       VD: as for the thorax

Positioning for MSK

  • GA generally required for pelvis, spine, head projections, or fractures
  • Spines: take separate lateral projections for the thorax, abdomen and neck. Don’t cram more than one region on the plate – obliquity degrades the image at the edges.
  • Heavy sedation is adequate for most extremities
  • For joints, ensure the joint is centered on the plate, and the mid diaphysis of each bone above and below is included
  • For digits, ensure the entire distal limb from carpus/tarsus distally is included.
  • Elbows, stifles + distal extremities: use a table-top technique
  • Pelvis: in medium/large breed dogs, use a grid technique
  • Shoulders: in large dogs are difficult. Consider using a grid technique
  • Digits: collimate out to include the carpus or the tarsus – this will help to orient for lateral and medial; use sticky tape to splay the digits for the lateral projection, to stop superimposition 

Perfect Positioning

Use a variety of positioning aids to help get straight and well-positioned images. No need to spend lots of money. Some of our favourites are:

Foam V-troughs:

Large pieces of foam, cut to size using an electric bread knife.

Ours are covered in vinyl (by a local bean-bag or foam shop) so they are easily wiped down with disinfectant between uses. We have three: small (cats and small dogs), medium (cattle dogs, kelpies etc.) and large (Labradors, giant breeds). Easy to get straight VD projections of the abdomen and thorax with these and useful for getting good pelvis, hip and spine radiographs.

Foam wedges:

In a variety of sizes, mostly as triangle, or thin rectangular wedges.

Some are H-shaped for resting the head. We cover ours in glad-wrap and remove and re-cover when they get grotty.

Sand-bags:

These are marvellous for positioning all animals. They are vinyl with a nylon loop sewn into the top. Fill three-quarters full with sand or kitty-litter, then they will bend over in half.

Wrap them around limbs, drape them over the pelvis or neck. The nylon loops are useful for hooking in extremities for MSK work in anaesthetised patients.

Ideal quantities and dimensions (cm)

  • 2x large 66 x 13 x 5; nylon handle 26cm long
  • 4x medium 50 x 11x 3.5; nylon handle 18cm long
  • 4x small 44 x 7 x 2.5; nylon handle 17cm long

  

With sedation, your patients should lie comfortably and straight for excellent positioning:

   

With these simple tips, you should be able to immeasurably improve the quality of your radiographs. After that, all you have to do is interpret them.  Of course, a friendly radiologist would be happy to help!

If you have any questions about how to take perfect diagnostic radiographs, just ask them in the comments section below

Zoe Lenard BVSc (Hons) FANZCVS (Radiol) is a Registered Specialist in Veterinary Radiology and is Co-Director at the Veterinary Imaging Centre and Perth Veterinary Specialists. Her interests include abdominal ultrasonography, the conversion of vet practice to "digital" imaging and cross sectional imaging.

Zoe is also the administrator/Treasurer of the Australasian Association of Veterinary Diagnostic Imaging (AAVDI)

Click here to visit the AAVDI Page in the Vetanswers Business Directory

 

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