Presentation
Shoulder instability. For MR arthrogram.
Patient Data
Posterior approach: I...
Posterior approach: Injection of contrast
Images from a shoulder/ glenohumeral arthrogram injection.
A 22G quincke is inserted targeting the inferomedial aspect of the humeral head. The run of images shows iodinated contrast extending along the infraspinatus muscle and not extending into the joint.
Posterior approach: I...
Posterior approach: Injection of contrast & then injectate
The 22G quincke needle is repositioned and iodinated contrasts show an intra-articular needle tip position with it extending into the axillary recess. The post-procedure image shows the arthrogram injectate has spread throughout the glenohumeral joint and into the long head of biceps tendon sheath.
Case Discussion
Shoulder/ glenohumeral arthrogram injections can be performed from an anterior or posterior approach.
In a posterior approach, the needle is passed through the infraspinatus and if contrast or the arthrogram solution is injected into the infraspinatus muscle as demonstrated, it is unlikely to effect the diagnostic accuracy of the MR arthrogram. This is opposed to an anterior approach through the rotator cuff interval, where the anterior cuff and anterior labrum are important aspects of the MRI in anterior shoulder instability and contrast in these structures would limit interpretation.