This is Barry Bellosis, one of the musculoskeletal radiology fellows at Stanford University. 24 year old with chronic right shoulder pain for two years. Concerned for labral tear with paralabral cyst. If there is concern for a torn labrum or paralabral cyst, MRI without contrast could be performed. On this MRI without contrast, we evaluate for the normal labrum. A normal labrum is hypo-intense or dark on all sequences. In our axial T2 FATSAT imaging here, we best demonstrate the posterior labrum and the anterior labrum, both with triangular shape and no increased signal. The superior labrum is best depicted on our coronal imaging such as this in T1 and T2 FATSAT showing normal morphology without increased signal in them. On a different patient, again MRI without contrast, we can see a torn labrum with small paralabral cyst here in the posterior labrum as demonstrated by the increased signal within the posterior labrum and in here a small paralabral cyst. This is in comparison to the normal labrum on the right. On a different patient, this is a 26-year-old American football player with shoulder pain and mild weakness. An MRI without contrast was performed. In the left-hand corner, we can see a paralabral cyst extending from the tear to the spinoglenoid notch. This is your glenoid and your scapular spine. This can also be seen in our coronal T2 FATSAT imaging showing this paralabral cyst extending from the posterior superior labrum to the spinoglenoid notch. Also seen here in Sagittal T2 FATSAT imaging. This is the same MRI without contrast from our prior patient. In this imaging, we have Sagittal T1 and Sagittal T2 FATSAT imaging. When we are evaluating muscles of the rotator cuff, we like to look at Sagittal T1. Just a quick review of our supraspinatus, our infraspinatus, and our teres minor, and our subscapularis. When we evaluate the muscle, we look at the muscle bulk, any signs of fatty infiltration or atrophy, and then we also look for any abnormal muscle signal which we look at in our Sagittal T2. The muscle bulk is preserved within the rotator cuff as you can see. When we look at our Sagittal T2 FATSAT imaging, we can appreciate increased T2 signal within the infraspinatus here that is concerning for denervation changes. This can also be seen in our coronal T2 FATSAT. We can see that it is a little bit more hyper intense or bright compared to the surrounding muscles here. When we look at it closely here, we can see that the paralabel cyst that we saw is in the spinoglenoid notch and that results in denervation within the infraspinatus. Now why do we only have it in our infraspinatus? Review of our anatomy demonstrate the suprascapular nerve passes through the suprascapular notch and then into the spinoglenoid notch. If the suprascapular nerve is affected in the suprascapular notch, then both the supraspinatus and infraspinatus are affected. If it's only affected in the spinoglenoid notch, then only the infraspinatus is affected.

2nd Edition, CASE 48

2nd Edition

Shoulder

labral tears

paralabral cysts

MRI

suprascapular nerve

infraspinatus muscle