Background: Spinal infections, including paraspinal and/or epidural abscesses and vertebral discitis and osteomyelitis, can have devastating consequences. The diagnostic imaging modality of choice has traditionally been magnetic resonance imaging (MRI) given the very high sensitivity and specificity, although the role of MRI in follow-up of spinal infections and how this relates to follow-up clinical status is poorly understood. We sought to understand the relationship between follow-up MRI and clinical status.
Methods: We conducted a retrospective review of adults with spinal infection to assess the relationship between follow-up MRI and clinical course. The degree of agreement between MRI and clinical follow-up was assessed using the Cohen kappa coefficient. A multinomial logistic regression model was applied to assess the impact of covariates in affecting the clinical outcome and MRI at follow-up independently.
Results: Ninety-eight patients met inclusion criteria during a 13-year period. We observed a lack of correlation between clinical follow-up status and MRI (κ = 0.065, P = 0.322). The McNemar-Bowker test for symmetry revealed that this disagreement was asymmetric (P < 0.001). Notably, clinical worsening was never associated with an improved MRI, and clinical improvement was overall not predictive of MRI result and vice versa.
Conclusions: Routine follow-up MRI does not seem to correlate with clinical follow-up among patients with spinal infections. The use of MRI without new clinical indications in routine follow-up testing should be interpreted with caution.