抄録
Background: Evaluation of the glenoid for traumatic anterior shoulder instability is essential and imaging studies by scapula 3DCT and shoulder MRI have become standardized. However, carcinogenic risks by CT radiation have been reported and avoidance would be preferred. We evaluated the glenoid in bony Bankert lesion(BBL) by 3DMRI and compared this with the findings by 3DCT.
Methods: Six-teen cases that underwent both 3DCT and 3DMRI for traumatic anterior shoulder instability from January 2010 to May 2012 were included. An orthopaedic surgeon and a radiologist who were blinded to each other assessed the findings by 3DCT and 3DMRI, using 3DCT as the gold standard. Based on the results of 3DCT as the gold standard, the sensitivity and specificity of 3DMRI for detection of BBL were determined. Statistical significances of the size of bony fragment and the angle of bony defect between these two methods were calculated.
Results: Four cases were diagnosed as BBL by 3DCT and 3DMRI. The sensitivity of BBL by 3DMRI was 100% and the specificity was 83-100%. As to the quantification of the size of bony fragment and the angle of bony defect, 3DMRI(15.9 ± 4.8%, 87.5 ± 34.8°) and 3DCT(18.7 ± 5.4%,80.0 ± 29.4°) showed no statistical difference(p=0.144, p=0.109).
Conclusion: The sensitivity and specificity of BBL by 3DMRI were useful. 3DMRI is a reliable method for evaluating BBL and glenoid morphology. The result of a preceding 3DMRI could indicate the need for a further 3DCT. 3DCT of the shoulder could be omitted from pre-operative evaluation for anterior shoulder instability.
