Comparison of magnetic resonance imaging with standing cervical radiographs for evaluation of vertebral canal stenosis in equine cervical stenotic myelopathy.

The research article compares the effectiveness of magnetic resonance imaging (MRI) to standing cervical radiographs for observing stenosis in the vertebral canal of horses suffering from cervical stenotic myelopathy (CSM). The conclusions drawn from the comparison indicate that MRI is a better predictive parameter than the standing radiographs due to the additional visual plane and measurement capabilities it offers, resulting in a more accurate identification of stenosis.

Objective of the Research

• The primary aim of the research was to investigate whether Magnetic Resonance Imaging (MRI) could offer a more accurate diagnosis of stenosis in horses suffering from Cervical Stenotic Myelopathy (CSM) than conventional standing cervical radiographs. This inquiry stemmed from the limitations of the standing radiographs, whose detailed assessment is restricted to the sagittal plane only.

Methodology

• Nineteen Thoroughbred horses diagnosed with CSM were analyzed in comparison with nine control Thoroughbred horses.
• Before their deaths, each of the horses was subjected to neurological examinations and standing cervical radiographs. Sagittal ratios were calculated from C3 to C7 based on these radiographs.
• Post-mortem MRI scans were conducted on their intact cervical column. Additionally, the spinal cord of each horse was examined histologically for further insights.
• The parameters for assessing vertebral canal, spinal cord, and intervertebral foramen were directly measured for analysis.

Results of the Study

• The study identified several inaccuracies in the determination of canal stenosis when using the standard minimal sagittal diameter intra-vertebral and inter-vertebral ratios derived from radiographic cervical canal height measurements.
• Contrarily, the post-mortem MRI measurements were found to predict sites of cord compression with higher accuracy in cases of CSM. These measurements entailed canal area and cord canal area ratios.
• Significant measurements were observed in several vertebral canal parameters when comparing CSM to control horses. However, no notable differences were found in the spinal cord measurements of both groups.

Conclusions

• When compared to the sagittal plane of the canal height, vertebral canal area and cord canal area ratio serve as better predictors for the location of cervical canal stenosis.
• Additional visual planes and measurements, particularly vertebral canal area and the cord canal area ratio, obtainable through MRI could provide a more precise identification of regions of canal stenosis than standing cervical radiographs.
• The findings from the study advocate the development and usage of MRI or computed tomography (CT) equipment that is capable of evaluating the cervical column of mature horses. This could drastically improve the evaluation process of patients suffering from CSM.