1) To describe the spectrum of normal and pathologic imaging features of the rotator cuff.

Lawrence.White@sinaihealthsystem.ca

1) Describe the normal anatomy and function of the labrum and articular cartilage of the glenohumeral joint. 2) Identify appropriate imaging techniques and protocols for assessment of the labrum and articular cartilage of the glenohumeral joint 3) Describe the spectrum of normal and pathologic MR imaging features of the labrum and articular cartilage of the glenohumeral joint.

ai5720@doctors.net.uk

Isolated teres minor denervation in the absence of a structural lesion involving the axillary nerve is not an uncommon finding on shoulder MRI. Pathologies such as rotator cuff injuries and axillary nerve traction injury have been mentioned. In our centre, we have identified a number of cases of teres minor oedema in patients with adhesive capsulitis. A study by Chafik et al (2013) described the complex anatomy of the teres minor muscle and found a combined fascia of the infraspinatous, teres minor, long head of triceps and deltoid muscle which forms a stout fascial sling attaching just medial to the inferior glenoid articular cartilage. They discovered that the primary motor branch of the teres minor runs inferior to this prior to entering the muscle. We believe that posterior inferior joint capsule involvement in adhesive capsulitis results in teres minor oedema and/or atrophy secondary to denervation of this primary motor branch.

This retrospective study analysed all MRI shoulders with a radiolological diagnosis of adhesive capsulitis between 2014-17. Each study was re-reviewed to assess the posterior joint capsule for thickening and its proximity to the described location of the stout fascial sling, the axillary neurovascular bundle and the teres muscle for oedema and/or atrophy.

There were a total of 59 cases with 'adhesive capsulitis' between 2014-2017. There were 38 males and 21 females. The age range was 23-74yrs with a mean age of 47.7yrs. 48(81%) patients had thickening of the posterior inferior joint capsule in close proximity to the described location of the fascial sling. Of these, 36(75%) patients had oedema and/or atrophy. 24(50%) patients had isolated teres minor oedema and 14(29%) patients had isolated muscle atrophy. No axillary bundle lesion were identified.

The primary motor branch of the teres minor muscle courses just inferior to the stout fascial sling insertion onto the glenoid neck before it becomes sub-fascial. Adhesive capsulitis with thickening of the posterior inferior joint capsule in close proximity to the stout fascial sling may result in denervation of the primary motor branch of the teres minor resulting in isolated oedema and/or atrophy.

Adhesive capsulitis should be excluded in symptomatic patients thought to have idiopathic isolated muscle oedema/atrophy undergoing surgical decompression of the Teres minor nerve.

liw142@ucsd.edu

To identify MR imaging features on shoulder arthrography which can distinguish between iatrogenic-induced extravasation and real IGHL complex lesions and to determine the diagnostic performance of these imaging features.

This was an IRB-approved, retrospective multi-institution study. 1,740 MR arthrograms were screened for extravasation through the IGHL complex. Exams were independently scored by 3 MSK fellowship-trained radiologists. The IGHL complex was assessed along the anterior-posterior and medial-lateral locations. Morphology of the disrupted margin was evaluated: maximum thickness of the portion floating in contrast (thin, <1mm; medium, 1-3mm; thick, >3mm), caliber change at the torn margin (tapering or reverse tapering), and regularity of the torn margin (single thin fascicle, mop-head, scarred). T-tests, chi-squared tests, and sensitivity/specificity were calculated.

35 exams fulfilled the strict inclusion criteria. Of those with true tears, 8/16 (50%) had a torn anterior band whereas 0/19 cases of iatrogenic induced extravasation demonstrated anterior band disruption (p<0.001). In those with iatrogenic induced extravasation, 12/19 (63.2%) had solitary extravasation through the posterior half of the axillary pouch, compared to none in true IGHL complex lesions (p<0.001). Thick ends were present in 10/16 (62.5%) of the true IGHL complex lesion group whereas 0/19 (0%) demonstrated this finding in the iatrogenic induced extravasation group (p < 0.001). Scarred margins were seen in 8/16 (50%) with true IGHL complex lesions and none of the iatrogenic induced extravasation cases (p<0.001). Presence of a torn anterior band, thick ligament, reverse tapered caliber, and scarred appearance of the torn margin were shown to be 100% specific and a torn posterior band demonstrated 84.2% specificity for true IGHL complex tears. The presence of solitary involvement of the posterior portion of axillary pouch demonstrated 63.2% sensitivity for iatrogenic induced contrast extravasation, but was 100% specific.

We have identified MR arthrogram features that can aid the radiologist in distinguishing between iatrogenic-induced extravasation and real IGHL complex lesions.

Discriminating between a true IGHL complex tear from iatrogenic extravasation can be difficult on shoulder MR arthrography, however we have identified features that may aid the radiologist.

To determine if direct magnetic resonance arthrography (MRA) is more cost-effective than a non-contrast magnetic resonance imaging (MRI) in the diagnsosis and management of superior labral anterior to posterior (SLAP) tears.

Our base case was a 25-year-old with clinical findings of a SLAP tear in whom an imaging test is being ordered for further management. Decision analysis software (TreeAge Pro) was used to create a model from the healthcare perspective to evaluate the cost-effectiveness of 4 imaging strategies: 3-Tesla (T) MRA, 3T MRI, 1.5T MRA and 1.5T MRI. Probability and utility estimates were obtained from published literature. Commercial insurance and Medicaid reimbursements were derived from 2017 Medicare rates. Effectiveness was measured in quality-adjusted life years (QALY) over a 2-year period and costs were calculated in 2017 U.S. dollars.

3T MRI is the least expensive ($6126) and most effective (1.62165 QALY) strategy for our base case and is dominant to 3T MRA ($6799, 1.6165 QALY), 1.5T MRA ($7036, 1.60407 QALY) and 1.5T MRI ($6965, 1.58446 QALY). 3T MRA becomes the most cost-effective option if the specificity of 3T MRI drops below 90.4% with a willingness-to-pay (WTP) threshold of $100,000. If 3T is excluded from the analysis, 1.5T MRA is dominant for our base case but 1.5T MRI becomes the most cost effective option if its specificity is higher than 80.3%. The results remained robust and did not change over a reasonable range of costs, utilities, probabilities and WTP thresholds in 1-way, 2-way and probabilistic sensitivity analyses.

3T MRI is the most cost-effective option for management of SLAP tears. If a 3T magnet is not available, 1.5T MRA is the most cost effective option. In both circumstances, the most cost effective option is the test with highest specificity.

MRA has been traditionally considered the test of choice when evaluating labral tears, including SLAP tears. This study, however, shows that if imaging is performed at 3T, MRI is the most cost effective option and may obviate the need for patients to undergo a more invasive test.

adam.zoga@jefferson.edu

http://abstract.rsna.org/uploads/2018/18000806/Zoga- post arthroscopy shoulder - handout RC504-06.pdf

1) To be comfortable evaluating radiographs of the shoulder after arthroscopic intervention. 2) To be prepared to select and prescribe an optimal MRI protocol. 3) To be able to identify common glenoid labrum repairs and glenoid augmentations.

bruce.forster@vch.ca

1) Identify imaging findings in AC and SC joint trauma and be able to indicate how imaging changes management.

kamran.munawar@nyumc.org

A major factor that impacts the long-term outcome and complication rates of total shoulder arthroplasty (TSA) is the preoperative posterior glenoid bone loss quantified by glenoid retroversion. The purpose of this study was to assess if glenoid retroversion angles vary significantly at different glenoid heights in patients with Walch B2 and B3 glenoid types. Glenoid version measurements were also compared between 'conventional' CT slices and 'true' axial slices.

386 consecutive CT shoulder studies performed for shoulder arthroplasty preoperative planning were retrospectively reviewed. Patients with B2 and B3 glenoid types were included. 'True axial' CT reconstructions were created using a validated technique. Two readers independently measured glenoid retroversion angles according to the Friedman method on true axial CT images using the 'intermediate' glenoid line at three glenoid heights: 75% (upper), 50% (equator) and 25% (lower). The 'clinical' glenoid version was measured on the conventional axial images and compared with the version measurement on the true axial images.

29 B2 and 8 B3 glenoid types were included. There was no statistically significant difference between the retroversion measurements performed by each reader at the three glenoid levels on the B2 or B3 glenoid types. Inter-reader correlation was substantial. There was a statistically significant difference in the mean glenoid retroversion measured on conventional versus true axial images for both B2 and B3 glenoid types, with 2° overestimation on conventional compared to true axial images (p=0.01).

We demonstrated that glenoid version can accurately be measured at any level between 25% to 75% of the glenoid height for Walch B2 and B3 types and that the conventional axial CT overestimates the degree of retroversion when compared with the true axial.

Glenoid retroversion measurement is a crucial component of the pre-operative evaluation of patients with advanced glenohumeral osteoarthritis and can be measured accurately on true axial images at the glenoid equator.

amarrd02@yahoo.co.in

The purpose of this study was to correlate the MR findings of adhesive capsulitis with clinical stages and thereby propose a MR staging system.

This study consisted of 74 patients with clinically diagnosed adhesive capsulitis. The edema of the inferior glenohumeral ligament, pericapsular edema , thickness of anterior band of IGHL and axillary pouch, thickness of coracohumeral ligament, obliteration of fat in the subcoracoid triangle were evaluated by MRI.

Thickening of the anterior band of IGHL showed most significant correlation with the clinical stages. The distribution of edema of IGHL and pericapsular edema also showed significant correlation with the clinical stages of adhesive capsulitis. Pericapsular edema and IGHL edema was not observed in stage IV. Based on the correlation between MR findings and clinical staging , we propose a MR staging of adhesive capsulitis. The thickness of anterior band of IGHL on humeral side in range of 4.5 + 0.9 mm with no obliteration of fat in the subcoracoid triangle seen in stage I and thickness of anterior band of IGHL on humeral side in range of 7.6 + 1.9 mm with no obliteration of fat in subcoracoid triangle seen in stage II. Obliteration of fat in subcoracoid triangle with mild edema of IGHL is seen in stage III and Obliteration of fat in subcoracoid triangle with no edema of IGHL is seen in stage IV.

MR is an useful tool for evaluation and prediction of clinical stage of adhesive capsulitis.

Imaging based grading system of adhesive capsulitis can aid in the identification of the stage of the disease even when the clinical manifestations are subtle. This helps in initiation of appropriate treatment to halt the disease progression , prevent the complications and avoid invasive treatment procedures.

federico.bruno.1988@gmail.com

To assess the ability of shoulder 3D MRA and additional ABER scans to quantify bipolar bone loss and detect on-track/off-track lesions in traumatic shoulder instability, using MPR CT images as a reference standard

We evaluated 23 consecutive patients (15 men, 8 women, mean age 27.6 years, range 19-46) with anterior shoulder instability. All patients were submitted to 3D-CT of the shoulder and direct shoulder MR Arthrography using three-dimensional (3D) isotropic PD sequences in standard and ABER position. Two observers evaluated the images twice in a randomized and blinded way to calculate the glenoid track, the Hill-Sachs interval and to predict engagement using the 'on-track/off-track' method. The intra- and inter-observer agreement were calculated

Of the 23 defect combinations, 14 were classified as non-engaging and 9 as engaging, using the 'on-track/off-track' method. The intra-observer reliability was 0.921 for 3D-CT and 0.786 for MR Arthrography . The inter-observer agreement ranged from 'substantial' to 'almost perfect' for both glenoid track and Hill-Sachs interval measurement (p<0.005). ABER MR Arthrography predicted engagement accurately in 21 cases (91.3%).

MR Arthrography using 3D isotropic PD sequences is a feasible approach for measuring bony defects in patients with anterior shoulder instability and bipolar bone loss using the 'on-track/off-track' method. The same sequence in ABER position showed and added value in direct prediction of the presence of engaging lesions

Prediction of engaging lesions using the glenoid track method represents a valuable tool for the surgeon, that can be used preoperatively to plan the type of stabilization procedure to be performed in patients with anterior shoulder instability

Erin.Fitzgerald@nyumc.org

1) Apply a systematic approach to evaluating extra-articular pathology about the shoulder. 2) Review commonly encountered osseous and soft tissue extra-articular shoulder pathology.

1) Review the MR imaging characteristics of normal anatomy, congenital variants and abnormalities of the long head of the biceps at the shoulder.

The long head of the biceps tendon originates at the supraglenoid tubercle and attaches to the superior labrum at the anchor. It courses through the glenohumeral joint where it is anchored by a pulley comprised of the superior glenohumeral ligament and coracohumeral ligament before it extends into the bicipital groove and down to the corresponding muscle of the upper arm. There can be anomalies of the biceps tendon ranging from absence to origin from the supraspinatus tendon. The supraspinatus aponeurosis is present in some individuals and lies in front of the biceps in the groove. This should not be mistaken for a tear. The tendon can become degenerated with tendinosis and can tear in the glenohumeral joint at any location. It often tears near the labral attachment and in younger patients this is associated with a SLAP lesion. In the region of the pulley proximal to the groove it can undergo tendinosis and the enlargement of the tendon prevents its excursion into the groove, producing pain upon motion of the biceps for everyday tasks. This is called the hourglass biceps. The biceps pulley may tear. The biceps is intimately associated with the subscapularis and supraspinatus tendons when it enters the bicipital groove. Tears of these tendons can be associated with biceps subluxation or dislocation. This has been classified by Habermayer. The biceps sheath is continuous with the glenohumeral joint, so fluid surrounding the biceps can be normal. Fluid in the sheath can also be associated with tenosynovitis in the groove. The tendon may tear at any location along its length. Treatment for biceps problems is usually resection of the proximal biceps (tenotomy) or resection of the proximal biceps with anchoring of the proximal portion in the humerus (tenodesis).