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[Low-field MR arthrography of the shoulder: early results using an open 0.2T MR system].

PURPOSE
To assess the practicability and image quality of doing MR arthrography of the shoulder using a 0.2T system.


PATIENTS AND METHOD
60 patients (24 with chronic instability, 36 with impingement syndrome) were examined in an open 0.2T MR apparatus (Magnetom Open, Siemens). After the intra-articular injections of 15-20 ml of a 2 mmol Gd-DTPA solution, coronary STIR, T1-weighted, sagittal and axial T2*-weighted FLASH 2D sequences were performed. 21 patients subsequently underwent surgery.


RESULTS
Image quality of the T1- and T2*-weighted FLASH 2D sequences was regarded as good or adequate and movement artifacts were minor or moderate. STIR sequences were statistically significantly worse in respect of image quality and movement artifacts (p < 0.001, p < 0.005). The sensitivity and specificity in the diagnosis of rotator cuff rupture as confirmed by surgery was 100% (labrum lesions 100%, 93%). Agreement in the diagnosis of rupture of the supraspinatus and infraspinatus tendons was 0.93 and 0.65.


CONCLUSION
MR arthrography of the shoulder using an open 0.2 T MR system provides adequate information concerning the intra articular structures of the joint. The disadvantage is the prolonged duration of the examination with the risk of poor image quality resulting from movement artifacts.