Comparison of ultrasonographic and computed tomographic imaging of equine thoracolumbar articular process joints.
Authors: Morgan Rhiannon E, Fiske-Jackson Andrew, Chang Yu-Mei
Journal: Equine veterinary journal
Summary
# Editorial Summary Thoracolumbar articular process joint (APJ) osteoarthritis is recognised as a significant source of equine back pain, yet optimal imaging protocols remain unclear. Morgan, Fiske-Jackson and Chang used cadaveric specimens to directly compare ultrasonographic and computed tomographic assessment of APJ pathology, evaluating agreement between imaging modalities and observers across different spinal regions. Periarticular bone modelling—a key marker of osteoarthritic change—demonstrated moderate agreement between CT and ultrasound in the caudal thoracolumbar spine (T15–L1), with particularly strong inter-observer reliability for ultrasound assessment at this location, though agreement deteriorated both cranially and distally. Joint space modification and APJ enlargement showed only fair inter-modality agreement, and wide confidence intervals across most measurements indicate uncertainty that warrants cautious interpretation, particularly given the small sample size of six spines. These findings support ultrasound as a valid tool for identifying bone remodelling in the caudal thoracolumbar APJs—the region most commonly implicated in clinical back pain—though practitioners should recognise the limitations of imaging agreement elsewhere in the spine and appreciate that ultrasonographic assessment may not fully capture all pathological features visible on CT. Further research with larger specimen numbers would strengthen these conclusions and help establish standardised protocols for back pain investigation.
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Practical Takeaways
- •Ultrasonography is a reliable alternative to CT for assessing periarticular bone modelling in thoracolumbar APJ osteoarthritis, offering a practical in-field diagnostic option
- •Caudal thoracolumbar APJ evaluation (T15-L1) shows better inter-modality agreement than mid-thoracic regions, making US more dependable in this location for clinical decision-making
- •Wide confidence intervals in the study highlight imaging limitations; practitioners should use US findings alongside clinical signs and consider CT for complex cases where diagnostic certainty is critical
Key Findings
- •Intra-observer agreement for US and CT grades ranged from moderate to perfect
- •Inter-modality agreement (CT vs. US) for periarticular modelling was moderate between T15-L1, but fair for joint space modification and APJ enlargement
- •Inter-observer agreement (US vs. US) for periarticular modelling was substantial between T15-L1, decreasing to fair between T10-T15
- •Periarticular modelling showed the best agreement between imaging modalities, supporting ultrasonography as a reliable diagnostic tool for bone changes in APJ osteoarthritis