Comparison of metric analysis of spinal structures, exemplarily of the ligamentum flavum, obtained with CT and MRI

Purpose: Comparison of metric analysis of spinal structures, exemplarily of the ligamentum flavum, obtained with computed tomography (CT) (soft tissue window and bone window) and magnetic resonance imaging (MRI) (T1 and T2 weighted images). Material and methods: Forty-six lumbar ligamenta flava of 46 patients (25 women and 21 men) were examined at a Somatom Plus 4 (Siemens, Erlangen, FRG) and at a 1.5T clinical scanner (Magnetom Vision, Siemens, Erlangen, FRG). Two independent neuroradiologists measured the thickness of the ligamenta flava in mm. Statistics included Pearson’s correlation coefficient and the intra-class correlation coefficient. Results: Mean values did not differ significantly. The correlation coefficients varied between 0.69 and 0.98. The best correlation occurred comparing the same techniques in different windowing and weighting (CT: r=0.98; MRI: r=0.95). Correlating different techniques the combination of CT bone window and T1 weighted images presented the best result (r=0.75). Conclusions: Because of the excellent correlation between the examined techniques CT as well as MRI can equally be used to measure distances of spinal structures.