Background: The two of the most common indications for magnetic resonance (MR)
imaging of the cervical spine include acute spine trauma and degenerative disease.
Objective: We aimed to correlate the measurements of the free area of the spinal canal (FASC), a
new approach to the cervical spinal canal compromise, with the Torg´s ratio quantification of the
Methods: A cross-sectional study including 50 cervical-spine MR evaluations of patients with
acute cervical trauma or degenerative disease was performed. We used multivariate analysis of covariance
(MANCOVA) to identify the type of lesion, intervertebral level and gender differences between
FASC and Torg´s ratio quantification of the cervical spine; age was the controlled covariate.
Correlates between FASC and Torg´s ratio were obtained at each intervertebral level.
Results: There was a non-significant interaction between the type of lesion, gender and intervertebral
levels between FASC and Torg´s ratio measurements, F (8, 456) 0.260, p = .978; Wilks' Lambda
0.991; with a small effect size (partial η2 = .005). Among the main effects, only the gender was
statistically significant: F (2, 228) = 3.682, p = .027. The age (controlled covariate) was non-significantly
related to FASC and Torg´s ratio quantification: F (2, 228) = .098, p = .907. The Pearson´s
correlation coefficient depicted a poor, non-significant agreement between FASC and Torg´s ratio.
Conclusion: FASC provides an integrative evaluation of the cervical spinal canal compromise in
acute, cervical spine trauma and degenerative disease. Further observations and correlation with
specific neurological symptoms, surgical findings and clinical outcomes are necessary to assess the
usefulness of FASC in clinical settings.