Evaluation of an optimised CT protocol for the assessment of suspected cauda equina syndrome and nerve root compression
Author Block: P. J. Dempsey, G. Lambe, D. T. Ryan, J. W. Power, A. Yates, G. Kenny, P. J. Macmahon; Dublin/IE
Purpose: The evaluation of suspected cauda equina syndrome and nerve root compression relies on urgent MRI. However, access to MRI can be limited in many healthcare systems, especially in the out-of-hours setting. CT, by comparison, is more readily accessible. The purpose of this study was to evaluate the diagnostic accuracy of an optimised CT lumbar spine protocol in the assessment of suspected cord and nerve root compression using MRI as the reference standard.
Methods or Background: Individuals presenting to the emergency department and referred for MRI for suspected nerve root compression were prospectively enrolled to have a CT spinal stenosis protocol in addition to MRI. Central canal and neural foraminal stenosis was qualitatively and quantitatively assessed at each lumbar level on CT by an expert radiologist blinded to the clinical information and outcome. Following a 4 week interval the process was repeated for each MRI.
Results or Findings: 59 individuals were included in the final analysis. In 22 (39%) cases no significant stenosis was identified. In a further 22 (37%) cases disc pathology was identified that was managed conservatively. 13 (22%) individuals proceeded to urgent surgical decompression. In one (2%) instance an alternative diagnosis was identified. The sensitivity, specificity, positive and negative predictive values for CT in detecting acute neural compression were 97% (CI: 82-99%), 97% (CI: 83-99%), 97% (CI: 92-99%) and 97% (CI 83- 99%) respectively.
Conclusion: CT accurately detected nerve compression and emergent surgical lesions. This can be a useful tool in selecting appropriate patients for emergent MRI in the on-call setting to allow for better emergency resource allocation.
Limitations: The study was limited by its relatively small sample size, its reliance on external multicentre validation, and from the lack of a universally agreed stenosis assessment method. This was a single centre study.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by an ethics committee.