MR Arthrogram Features That Can Be Used to Distinguish Between True Inferior Glenohumeral Ligament Complex Tears and
Wilbur Wang1, Brady K Huang1, Matthew Sharp1,2
11 Department of Radiology, University of California, San Diego Medical Center, San Diego, CA.
Objective:
The purpose of this study is to identify features seen at shoulder MR arthrography that distinguish between iatrogenic contrast material extravasation and inferior glenohumeral ligament (IGHL) complex tears.
Materials And Methods:
MR arthrograms (n = 1740) were screened for extravasation through the IGHL complex. Cases were defined on the basis of surgical findings or definitive lack of extravasation in a fully distended joint immediately after contrast agent injection. The location of the disruption and the morphologic features of the torn margin were assessed and compared between groups.
Results:
Anterior band disruption was present in eight of 16 patients with true tears and in zero of 19 patients with iatrogenic contrast material extravasation (p < 0.001). Isolated extravasation through the posterior half of the axillary pouch was present in 12 patients with iatrogenic extravasation, compared with none of the patients with true tears (p < 0.001). Thick ends were present in 10 of the true tears, whereas none of the cases of iatrogenic extravasation showed this finding (p < 0.001). Scarred margins were seen in eight true tears and none of the iatrogenic extravasation cases (p < 0.001). The presence of a torn anterior band, thick ligament, reverse-tapered caliber, and scarred appearance of the torn margin were shown to be 100.0% specific, and a torn posterior band showed 84.2% specificity for true tears. The presence of isolated involvement of the posterior portion of axillary pouch showed 63.2% sensitivity and 100.0% specificity for iatrogenic extravasation.
Conclusion:
A torn anterior band, a thickened ligament (> 3 mm), reverse-tapered caliber, and scarred margin were 100.0% specific for a tear. Isolated disruption of the posterior axillary pouch was 100.0% specific for iatrogenic extravasation.
Insights
Shoulder MR arthrography can differentiate iatrogenic contrast extravasation from inferior glenohumeral ligament tears. Specific features like torn anterior bands and scarred margins indicate true tears, while posterior axillary pouch involvement suggests extravasation.
Area of Science:
- Orthopedic Imaging
- Radiology
- Shoulder Anatomy
Background:
- Distinguishing iatrogenic contrast extravasation from inferior glenohumeral ligament (IGHL) complex tears on MR arthrography is crucial for accurate diagnosis and treatment planning.
- MR arthrography is a key imaging modality for evaluating shoulder pathology, including ligamentous injuries.
Purpose of the Study:
- To identify specific imaging features on shoulder MR arthrography that differentiate between iatrogenic contrast material extravasation and IGHL complex tears.
- To improve diagnostic accuracy in cases of suspected shoulder joint capsule or ligament injury.
Main Methods:
- Retrospective review of 1740 shoulder MR arthrograms.
- Cases were categorized based on surgical findings or definitive lack of extravasation post-injection.
- Assessment and comparison of the location and morphologic features of disruptions between true tears and iatrogenic extravasation groups.
Main Results:
- Torn anterior bands (100% specific), thickened ligaments (>3mm), reverse-tapered caliber, and scarred margins were highly specific for true IGHL tears.
- Isolated posterior axillary pouch extravasation (100% specific) was indicative of iatrogenic contrast material extravasation.
- Torn posterior bands showed 84.2% specificity for true tears.
Conclusions:
- Specific morphologic features on MR arthrography can reliably distinguish between IGHL tears and iatrogenic contrast extravasation.
- Identifying a torn anterior band, thickened ligament, reverse-tapered caliber, or scarred margin strongly suggests a true tear.
- Isolated posterior axillary pouch disruption is a definitive sign of iatrogenic extravasation.
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