46TH
ANNUAL
CONGRESS
OF
THE
SAEVA
SKUKUZA
16-‐20
FEBRUARY
2014
37
Cartilage imaging of the horse
Carstens A*
Section Diagnostic Imaging, Department of Companion Animal Clinical Studies,
Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110
With the rapid rate of technological advancement, imaging of the horse joint has
progressed with leaps and bounds. Specific areas of the joint are better suited to
certain imaging modalities with bony structures generally visualized using radiography
and computed tomography, and soft tissue structures such as the surrounding
tendons and ligaments, the joint capsule, synovium, joint space and intra-articular
ligaments more optimally visualized by using ultrasonography and magnetic
resonance imaging. There is, however overlap in the visualization of all these
structures using all the imaging modalities. Scintigraphy is a more functional modality,
resulting in localization of the lesion, with poor visualization of the anatomical
structure involved.
Articular cartilage is not visible using radiography and conventional computed
tomography, although intra-articular contrast may assist when cartilage defects are
present.
Ultrasonography and magnetic resonance imaging (MRI) can give much additional
information on the integrity and health of articular cartilage. The focus of most
research in horse cartilage imaging is on MRI of cartilage and particularly determining
which sequences result in optimal cartilage imaging. Cartilage mapping utilizing a
series of T1 (post-gadolinium – delayed gadolinium enhanced MRI of cartilage –
dGEMRIC) sequences and T2 series of sequences can quantify the amount of
pathologic cartilage present in osteoarthritic joints. The very thin cartilage found in
most equine distal limb joints (often only 1mm thick) presents a challenge optimizing
resolution.
Ultrasonography of cartilage can be utilized to determine the presence of cartilage
pathology. It requires high frequency transducers (minimally 7.5 to 13MHz) to result
in optimal resolution of the thin cartilage. Ultrasonography of joints with
osteoarthrosis and osteochondrosis, whether osteochondritis dissecans (OCD) or
subchondral cyst-like lesions have been reported, in one with ultrasonography being
found to be superior to radiography in diagnosing OCD in the femoropatellar joint.
The advantage of ultrasonography is that it can be used as a horse-side diagnostic
imaging tool without transportation to a referral facility for MRI scanning.
This presentation highlights the types of images acquired of cartilage in a selection of
equine joints using the different modalities as well as what is current in equine
cartilage imaging.
Selected References
1.
Bourza C, Alexander K, Rossier Y, Laverty S. Comparison of radiography and
ultrasonography for the diagnosis of osteochondritis dissecans in the equine femoropatellar
joint. 2009 Equine Vet. J. 41:686-692.
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