Computed tomography of the equine caudal spine and pelvis: Technique, image quality and anatomical variation in 56 clinical cases (2018-2023).
Authors: Ogden Nadine Kristina Elise, Winderickx Katja, Bennell Alison, Stack John David
Journal: Equine veterinary journal
Summary
# Editorial Summary Computed tomography of the equine caudal spine and pelvis has remained largely unexplored in live horses until now, despite the diagnostic superiority of cross-sectional imaging for this anatomically complex region. Ogden and colleagues retrospectively analysed 56 horses and ponies (aged 8 months to 20 years, weighing 85–680 kg) that underwent CT examination under general anaesthesia using wide-bore machines, with scanning times averaging 30 minutes and no adverse anaesthetic events recorded. All images achieved diagnostic quality, though the study revealed substantial anatomical variation in this population—including differing locations of the widest interspinous space, incidental spina bifida in lumbar and sacral vertebrae, shape variations in the final lumbar vertebra, and variable patterns of intertransverse joint fusion and remodelling. Image quality degradation in larger horses proved problematic, with beam hardening artefacts from pelvic bone and metallic hardware limiting soft tissue evaluation, whilst the upper weight limit for reliable imaging remains unknown and depends on individual scanner specifications. For practitioners, this work establishes that CT of the caudal spine and pelvis is a safe, viable diagnostic tool when appropriate equipment is available, though clinicians should recognise that anatomical variation is the norm rather than the exception in this region, and should anticipate imaging limitations in larger individuals.
Read the full abstract on PubMed
Practical Takeaways
- •CT of the caudal spine/pelvis is a safe, anaesthesia-friendly diagnostic option for equine cases—no procedural complications were observed in this large series.
- •Expect significant anatomical variation in normal horses in this region; what appears abnormal may be normal variation, so imaging should be interpreted cautiously against clinical signs.
- •Be aware that image quality limitations exist for larger horses; soft tissue assessment may be compromised, potentially limiting diagnostic utility in draft breeds and larger individuals.
Key Findings
- •CT imaging of the caudal spine and pelvis was safe with no adverse events recorded in 56 horses ranging from 8 months to 20 years old under general anaesthesia (mean duration 30 minutes).
- •All 56 horses produced diagnostic quality images, with anatomical variations common including variable location of widest interspinous space, spina bifida presence in lumbar and sacral spine, and intertransverse joint positioning.
- •Image quality degradation occurred in larger horses due to noise and beam hardening artefacts, with soft tissue interpretation compromised in the largest individuals.
- •CT examination of caudal spine and pelvis using wide-bore machines with modified patient infrastructure is a viable diagnostic technique for equine practitioners.