MRI may determine severity, location of abnormalities in shoulder instability
Click Here to Manage Email Alerts
WAIKOLOA, Hawaii — MRI can be used to determine the chronicity, severity and location of abnormalities in patients with traumatic shoulder instability, according to a presenter at Orthopedics Today Hawaii.
With labral tear as the “hallmark of instability on MRI,” previously published research has shown MRI alone provides good sensitivity and specificity for identifying labral tears, while MR arthrography provides better sensitivity and specificity, according to Pamela J. Lund, MD. She added 3 Tesla MRI and MR arthrography provide better sensitivity and specificity compared with standard MRI.
“Remember low field, these 0.2 Tesla, these open MRIs are not going to give you good sensitivity, so be aware of that when you’re looking at your MRI studies,” Lund said in her presentation here.
Lund noted it is important for surgeons to obtain high-field MRIs. She added that she likes to use a flexed coil that transmits and receives signals and has a total scan time of 15 to 20 minutes.
“We do fluid- and fat-sensitivity sequences, as we do in all our MRI studies,” Lund said.
In patients with shoulder instability undergoing an arthrogram, Lund said she obtains an abduction external rotation (ABER) view, which provides long axis images.
“We also do an oblique view if the patient cannot perform the ABER with a recent dislocation,” she said.
The published literature has shown both CT and MRI scans are accurate for assessing patients with both glenoid bone loss and Hill-Sachs lesions, also known as bipolar bone loss, according to Lund.
“For measuring glenoid bone loss, you can pick your poison,” Lund said. “When you’re doing the bipolar type of measurements, you’re going to be using the best fit circle and the surface area method. Some of these methods, of course, use the opposite shoulder for superimposing the glenoid on one another and they’re CT techniques, so those are not as easy to use practically.”
Collapse
Lund PJ. Shoulder MRI interpretation: Traumatic and atraumatic instability. Presented at: Orthopedics Today Hawaii. Jan. 9-13, 2022; Waikoloa, Hawaii.
Read more about
Click Here to Manage Email Alerts