Computed tomography identified mineralisation of the longitudinal odontoid ligament of the horse is associated with age and sex but not with the clinical sign of head shaking.

Mineralisation of the longitudinal odontoid ligament has recently been identified in three horses undergoing computed tomographic (CT) examination, but published studies describing the clinical relevance of this finding are currently lacking. The objective of this retrospective, analytical, cross-sectional study was to investigate the relationship of this image finding to primary presenting complaint, age, breed, use and sex of the patient, and determine any association to the clinical signs of head shaking, neck pain or restricted range of neck motion. Computed tomographic images of 96 horses undergoing examination of the head and cranial cervical spine, for a variety of clinical reasons, were assessed for the presence of mineralisation within the longitudinal odontoid ligament. Clinical records were reviewed; presenting problem, signalment, clinical signs and final diagnoses were recorded and potential associations of presenting primary problem, signalment and individual clinical signs with mineralisation in the longitudinal odontoid ligament investigated, using univariable and multivariable ordinal logistic regression analysis. Final multivariable analysis confirmed significant associations of increasing severity of mineralisation with increasing age (P = .002) and being female (P = .038). There was no association of mineralisation of the longitudinal odontoid ligament with the syndrome of idiopathic head shaking or other clinical signs investigated in this sample of horses. Authors therefore recommend that the clinical significance of mineralisation of the longitudinal odontoid ligament be interpreted cautiously for equine CT studies.

CT more accurately detects foreign bodies within the equine foot than MRI or digital radiography.

Identification and characterization of foreign bodies in the distal limb of horses poses a diagnostic challenge. The aims of this prospective experimental cadaver study were to describe the appearance of five foreign body materials within the equine hoof using CT, MRI, and digital radiography (DR) and to compare interrater agreement among three reviewers. Fifty foreign bodies consisting of five materials were implanted at a solar location or a coronary location in 25 equine cadaver feet. The images were reviewed by three equine veterinarians experienced in advanced imaging interpretation, who were blinded to the material of the foreign body. Foreign bodies were graded on visibility and appearance. Sensitivity and specificity were calculated for accurate identification of the different materials. Interrater agreement was assessed using Fleiss' kappa. Computed tomography had higher visibility score, sensitivity/specificity, and interrater agreement for detection of all materials; particularly slate, glass, and dry wood, compared to the other imaging modalities. Soaked wood and plastic had lower sensitivity (31-33%) on CT with a similar attenuation of the two materials. Foreign bodies were often visible on MRI, although with similar appearance and unclear details. On DR, only slate and glass were visible. The interrater agreement for identifying the correct material was almost perfect for slate, glass, and dry wood (κ = 0.92-1.00) and poor for plastic and soaked wood (κ < 0.20) on CT. Interrater agreement was poor for all materials on MRI and DR (κ < 0.20), with the except for fair (κ = 0.28) for slate on DR and moderate (κ = 0.28) for soaked wood on MRI.