Novel imaging protocol enables myelography of the cervical vertebral column using computed tomography with flexion and extension comparable to x-ray.

Abstract

BACKGROUND: Radiographic myelography is the traditional diagnostic method for detecting cervical spinal cord compression in horses but it is limited by superimposition and restriction to sagittal plane imaging. Computed tomography (CT) and CT myelography overcome many of these limitations yet previous CT protocols have not allowed dynamic imaging in flexion and extension comparable to radiographs. OBJECTIVES: To describe and evaluate a novel CT myelography protocol that enables imaging of the equine cervical vertebral column (Cto C/T) in flexion, neutral, and extension, and to compare intervertebral angle measurements with those obtained from radiographic myelography. STUDY DESIGN: Prospective clinical study. METHODS: Eight horses with clinical signs related to the cervical vertebral column underwent CT myelography and radiographic myelography under general anaesthesia. A mobile gantry CT system combined with a custom support platform enabled controlled repositioning of the cervical vertebral column. Intervertebral angles (Cto C/T) were measured in flexion, neutral, and extension by three blinded image reviewers. Agreement between modalities was assessed using ANOVA, Bland-Altman plot, and concordance correlation coefficients. RESULTS: The entire dynamic CT myelography protocol was completed within 45 min. Across all positions and cervical segments, no statistically significant differences were found between CT and radiographic myelography angle measurements (p > 0.01). All horses recovered uneventfully from anaesthesia, and no contrast-related adverse effects were observed. MAIN LIMITATIONS: Small sample size and the absence of repeated intra-observer measurements. Intervertebral angles served as a proxy for motion but did not directly assess the degree of spinal cord compression. CONCLUSIONS: Dynamic CT myelography is feasible, safe, and provides positional sensitivity comparable to radiographic myelography, while overcoming the limitations of superimposition and enabling multiplanar evaluation. This novel protocol offers a reliable diagnostic alternative for assessing cervical spinal pathology in horses and allows complete coverage of the cervical vertebral column from Cto T.