Comparison of Magnetic Resonance Imaging and Computed Tomography for Evaluation of Cervical Vertebral Nerves and Synovial Tissues in Horses with Cervical Spinal Disease.

Pathology of the cervical spine is an important cause of poor performance in sport horses. Computed tomography (CT) and magnetic resonance imaging (MRI) have improved musculoskeletal diagnostic capabilities. CT is well-suited to assess osseous pathology, although it is limited for assessing soft tissues. MRI, the gold standard for imaging soft tissues, cannot be used for antemortem imaging of the equine cervical spine. The diagnostic potential of CT for evaluating soft tissues of the equine cervical spine compared to MRI is not well-defined and warrants investigation. Postmortem MRI was performed on eighteen horses euthanized for clinical and CT myelographic findings of cervical disease. Synovial and vertebral nerve tissue abnormalities were graded on MRI and CT. Grading of radiologists' confidence in identification of synovial tissues and vertebral nerves on MRI and CT was performed. Hounsfield unit (HU) measurements of synovial and vertebral nerve tissues were recorded. MRI was superior at evaluating, and radiologists had greater confidence in MRI for identifying synovial and vertebral nerve tissues. Agreement between measurements of HU was variable and poorest for vertebral nerves. Findings support MRI's superiority for the evaluation of equine cervical vertebral nerves and synovial tissues. Caution should be exercised when interpreting CT findings of these tissues of horses.