MRI can assess glenoid bone loss after shoulder luxation: inter- and intra-individual comparison with CT.

Objective: Computed tomography (CT) is the gold standard for evaluating glenoid bone loss in patients with glenohumeral dislocations. The aim of this study was to verify if magnetic resonance imaging (MRI) can quantify the area of bone loss without any significant difference from CT.
Materials and Methods: Twenty-three patients, who had experienced one or more post-traumatic unilateral glenohumeral dislocations, underwent MRI and CT. MR and multiplanar reconstruction CT images were acquired in the sagittal plane: the glenoid area and the area of bone loss were calculated using the PICO method. Mean values, percentages, Cohen's kappa coefficients and Bland-Altman plots were all used to confirm the working hypothesis.
Results: The mean glenoid surface area was 575.29 mm(2) as measured by MRI, and 573.76 mm(2) as measured by CT; the calculated mean glenoid bone loss was respectively 4.38% and 4.34%. The interobserver agreement was good (k>0.81), and the coefficient of variance was 5% of the mean value using both methods. The two series of measurements were within two standard deviations of each other.
Conclusions: MRI is a valid alternative to CT for measuring glenoid bone loss in patients with glenohumeral dislocation.