CT of the canine elbow for medial coronoid disease

Why medial coronoid disease deserves a clear answer

Medial coronoid process disease is a common cause of thoracic limb lameness in dogs. In a retrospective study of lame large-breed dogs (Mostafa et al., Veterinary Radiology & Ultrasound, 2018), its prevalence was 20.8%, and Labrador and Golden Retrievers were the most affected purebred dogs. The authors note that CT and arthroscopy are superior to radiography for this diagnosis, while radiography remains the most available modality in practice.

Where radiographs fall short

Radiographs miss a proportion of diseased elbows, and the proportion depends on the population:

• Screening population. In 424 elbows with CT as the reference (Vali et al., Veterinary Sciences, 2025), radiography identified 17 of 26 affected joints (65%) and had a specificity of 93%. At that low prevalence (6%), the positive predictive value was 37% and the negative predictive value 98%. The authors conclude that CT is the preferred screening technique when it is available.
• Difficult cases. In dogs presented for an official second opinion (Wennemuth et al., Veterinary and Comparative Orthopaedics and Traumatology, 2020), radiography had a sensitivity of 83.6% and a specificity of 83.5% compared with CT. A false-negative radiograph was significantly associated with a fissure line on CT, and the authors strongly recommend CT in appeal cases.
• Age. In Labrador Retrievers with medial coronoid disease (Lau et al., Veterinary Surgery, 2015), radiographic sensitivity was 93.8% in dogs aged 12 months or less and 73.3% in older dogs. CT sensitivity was 93.8% and 66.7% in older dogs.

That last result is a reminder that CT is not a perfect test either. In older dogs, the most common arthroscopic finding was osteochondromalacia, a cartilage change rather than a bony fragment.

CT and arthroscopy answer different questions

• CT can disagree with arthroscopy. In 101 elbows examined with both (Moores et al., Veterinary Surgery, 2008), some CT signs were associated with arthroscopic lesions and others were not. The absence of CT signs, or of arthroscopic abnormalities, did not rule out elbow lesions.
• Cartilage needs a direct look. In elbows with medial compartment erosion (Coppieters et al., Veterinary Radiology & Ultrasound, 2016), CT and arthroscopy agreed on coronoid fragmentation but not on the subchondral defect of the humeral condyle. Some fragments seen on CT could not be found at arthroscopy. The authors conclude that estimating the extent of cartilage lesions still requires arthroscopy.
• Incongruence is method-dependent. In 24 young large-breed dogs (Griffon et al., Veterinary Surgery, 2018), radioulnar incongruence was diagnosed in 26% of elbows on radiographs, 35% on CT, 78% by CT measurement (step of 2 mm or more) and 57% at arthroscopy. Agreement with arthroscopy was poor to fair, and CT did not reliably predict the arthroscopic assessment.

In practice this usually means CT maps the bone and guides the decision to scope, while arthroscopy grades the cartilage and treats what it finds.

Elbow CT protocol at a glance

For medial coronoid disease, the acquisition choice that matters most is thin slices. In 168 CT studies of dogs that all had arthroscopy (Zweifel et al., Veterinary and Comparative Orthopaedics and Traumatology, 2020), 1-mm slices gave sharper bone contours and the highest fragment detection rate, and slices of 2 mm or more significantly affected fragment detection.

What the radiologist looks at

The radiologist weighs each CT sign against what the evidence says it predicts at arthroscopy:

Finding on CT	What the evidence shows
Fragment of the medial coronoid process	Associated with a displaced fragment and with cartilage erosion of the coronoid and humeral condyle at arthroscopy (Moores et al.)
Fissure line	Significantly associated with a false-negative radiograph (Wennemuth et al.)
Irregular radial incisure of the ulna	Associated with cartilage erosion of the medial coronoid process (Moores et al.)
Osteophytes	Associated with an abnormal arthroscopy; osteophyte grade correlated moderately with medial compartment cartilage erosion grade (rs = 0.44–0.48) (Moores et al.)
Advanced medial compartment erosion	Periarticular osteophytosis in 100%, abnormal coronoid shape and a subchondral bone defect of the medial humeral condyle in 96.4% of 56 elbows (Coppieters et al.)

Reading is also partly subjective. In a study of eight observers (Shimizu et al., Journal of Small Animal Practice, 2015), agreement was fair to moderate for calling medial coronoid disease, moderate to almost perfect for fragmentation, and poor for grading sclerosis.

What your report will include

Every Veheri case is read by a radiologist or neurologist, and when you order you can choose Diplomate-only reporting or the full specialist panel. You can chat directly with the specialist assigned to your case, and a simplified pet owner report helps you explain the findings to the owner.

When you take the report forward:

• A CT without signs does not close the question: it did not rule out elbow lesions.
• Cartilage damage is best graded at arthroscopy, because the extent of cartilage lesions still requires arthroscopy.
• Incongruence on CT should be read with care, because CT did not reliably predict the arthroscopic assessment.
• Older dogs with a negative CT may still have cartilage disease, since CT sensitivity was lower in dogs over 12 months.
• Planning: it is worth discussing CT and arthroscopy with the surgeon before the first anaesthetic.

What to include when you request an elbow CT report

• signalment: age, breed and sex
• weight, and remember that sensitivity of both radiographs and CT differs with age
• duration of lameness, which limb, and response to rest or analgesia
• whether the scan is for a lame dog, breeding screening or an appeal
• previous radiographs and their reports, so the radiologist can compare
• any previous elbow surgery or arthroscopy

How Veheri can help

Veheri’s radiologists report veterinary CT studies remotely for clinics, and we offer expert support for CT protocols, positioning and acquisition. For the practical side of scanning, see mastering veterinary elbow CT and why contrast-enhanced CT helps limping dogs.