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Objectives: To evaluate and compare the diagnostic performance of CT-like images based on a 3D T1-weighted spoiled gradient-echo sequence (T1 GRE), an ultra-short echo time sequence (UTE), and a 3D T1-weighted spoiled multi-echo gradient-echo sequence (FRACTURE) with conventional CT in patients with suspected osseous shoulder pathologies., Materials and Methods: Patients with suspected traumatic dislocation of the shoulder (n = 46, mean age 40 ± 14.5 years, 19 women) were prospectively recruited and received 3-T MR imaging including 3D T1 GRE, UTE, and 3D FRACTURE sequences. CT was performed in patients with acute fractures and served as standard of reference (n = 25). Agreement of morphological features between the modalities was analyzed including the glenoid bone loss, Hill-Sachs interval, glenoid track, and the anterior straight-line length. Agreement between the modalities was assessed using Bland-Altman plots, Student's t-test, and Pearson's correlation coefficient. Inter- and intrareader assessment was evaluated with weighted Cohen's κ and intraclass correlation coefficient., Results: All osseous pathologies were detected accurately on all three CT-like sequences (n = 25, κ = 1.00). No significant difference in the percentage of glenoid bone loss was found between CT (mean ± standard deviation, 20.3% ± 8.0) and CT-like MR images (FRACTURE 20.6% ± 7.9, T1 GRE 20.4% ± 7.6, UTE 20.3% ± 7.7, p > 0.05). When comparing the different measurements on CT-like images, measurements performed using the UTE images correlated best with CT., Conclusion: Assessment of bony Bankart lesions and other osseous pathologies was feasible and accurate using CT-like images based on 3-T MRI compared with conventional CT. Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT., Clinical Relevance Statement: In an acute trauma setting, CT-like images based on a T1 GRE, UTE, or FRACTURE sequence might be a useful alternative to conventional CT scan sparing associated costs as well as radiation exposure., Key Points: • No significant differences were found for the assessment of the glenoid bone loss when comparing measurements of CT-like MR images with measurements of conventional CT images. • Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT whereas the FRACTURE sequence appeared to be the most robust regarding motion artifacts. • The T1 GRE sequence had the highest resolution with high bone contrast and detailed delineation of even small fractures but was more susceptible to motion artifacts., (© 2023. The Author(s).)

Background: Shoulder osteoarthritis causes severe pain and functional disability. Preventive surgical procedures aiming to halt the progression of degenerative changes are increasingly applied. However, no MRI-based score exists that may be applied for scoring of osteoarthritic changes and their progression., Purpose: To establish a semiquantitative MRI-based shoulder osteoarthritis severity (SOAS) evaluation system and to test its reliability., Study Type: Retrospective., Subjects: A total of N = 60 patients (73.2 ± 7.3 years; 30/60 female) was included; n = 15 subjects for each of the four radiographic grades of osteoarthritis (Samilson score 0 to 3)., Assessment: Based on the MRIs of the shoulder, the SOAS scoring system was created. All MRIs were assessed by six readers. The severity of degeneration was evaluated for: rotator cuff, labral-bicipital-complex, cartilage, osseous findings, joint capsule, and acromion. The total SOAS score ranged between 0 (absence of osteoarthritis) and 100 (most severe osteoarthritis). SOAS scores were correlated with radiographic Samilson, Hamada and Kellgren-Lawrence (KL) gradings., Statistics: Pearson correlations, t-tests, receiver operating characteristics (ROC) and interclass correlation coefficients (ICC)., Results: Intra- (ICC = 0.99) and interreader agreement (ICC 0.96-0.98) for the total SOAS score was excellent. The range of SOAS scores was from 1 to 88. SOAS correlated significantly with radiographic Samilson and KL scores (R = 0.82, P < 0.001), but not with Hamada scores (R = -0.07, P = 0.60). The highest correlations with Samilson scores were found for cartilage (R = 0.82, P < 0.001) and osseous findings (R = 0.86, P < 0.001). SOAS scores were significantly different between different Samilson grades (Samilson 0, 13.4 ± 7.6; Samilson 1, 26.0 ± 9.1; Samilson 2, 38.2 ± 19.2; Samilson 3, 65.5 ± 13.0; P < 0.05). The ability of the SOAS score to predict incident radiographic shoulder OA (KL grade ≥2) was excellent (AUC = 0.91; P < 0.001)., Data Conclusion: The newly developed semiquantitative MRI-based SOAS score represents the severity of global shoulder OA and structure-specific shoulder degeneration with excellent reliability in a standardized manner and may therefore be helpful in MRI research studies of the shoulder., Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018., (© 2018 International Society for Magnetic Resonance in Medicine.)

The rotator interval is an anatomically complex region of the shoulder joint that is difficult to evaluate on clinical examination and by imaging. Abnormalities of its components may contribute to instability, shoulder stiffness, and pain and are challenging to diagnose and treat. This article gives an overview of the anatomy, MR anatomy, and normal variants of the rotator interval, together with basic technical aspects of MR imaging of this area. Pathologic conditions of the rotator interval capsule, the long head of biceps tendon, and the pulley system are reviewed and illustrated with several clinical examples., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objective: To evaluate diagnostic signs and measurements in the assessment of capsular redundancy in atraumatic multidirectional instability (MDI) of the shoulder on MR arthrography (MR-A) including abduction/external rotation (ABER) images., Methods: Twenty-one MR-A including ABER position of 20 patients with clinically diagnosed MDI and 17 patients without instability were assessed by three radiologists. On ABER images, presence of a layer of contrast between the humeral head (HH) and the anteroinferior glenohumeral ligament (AIGHL) (crescent sign) and a triangular-shaped space between the HH, AIGHL and glenoid (triangle sign) were evaluated; centring of the HH was measured. Anterosuperior herniation of the rotator interval (RI) capsule and glenoid version were determined on standard imaging planes., Results: The crescent sign had a sensitivity of 57 %/62 %/48 % (observers 1/2/3) and specificity of 100 %/100 %/94 % in the diagnosis of MDI. The triangle sign had a sensitivity of 48 %/57 %/48 % and specificity of 94 %/94 %/100 %. The combination of both signs had a sensitivity of 86 %/90 %/81 % and specificity of 94 %/94 %/94 %. A positive triangle sign was significantly associated with decentring of the HH. Measurements of RI herniation, RI width and glenoid were not significantly different between both groups., Conclusions: Combined assessment of redundancy signs on ABER position MR-A allows for accurate differentiation between patients with atraumatic MDI and patients with clinically stable shoulders; measurements on standard imaging planes appear inappropriate., Key Points: MR arthrography has the possibility to accurately identify patients with atraumatic MDI. Imaging of the shoulder in abduction and external rotation provides additive information. Capsular enlargement of the shoulder can be diagnosed on MR arthrography.

Purpose: To retrospectively determine the diagnostic accuracy of magnetic resonance (MR) arthrography of the shoulder in the evaluation of lesions of the biceps pulley and to evaluate previously described and new diagnostic signs., Materials and Methods: Institutional review board approval was obtained; the requirement for informed consent was waived. MR arthrograms of 80 consecutive patients (mean age, 34.2 years; 53 male, 27 female) with arthroscopically proved intact or torn pulley systems were assessed for the presence of a pulley lesion by three radiologists who were blinded to arthroscopic results. Criteria evaluated were displacement of the long head of the biceps tendon (LHBT) relative to the subscapularis tendon on oblique sagittal images (displacement sign), medial subluxation of the LHBT on transverse images, nonvisibility or discontinuity of the superior glenohumeral ligament (SGHL), presence of biceps tendinopathy, and rotator cuff tears adjacent to the rotator interval., Results: There were 28 pulley lesions noted at arthroscopy. For observers 1, 2, and 3, respectively: MR arthrography showed a sensitivity of 89%, 86%, and 82% and a specificity of 96%, 98%, and 87% in the detection of pulley lesions. Nonvisibility or discontinuity of the SGHL was sensitive (79%, 89%, and 79%) and specific (83%, 79%, and 75%). With the displacement sign, sensitivity was 86%, 82%, and 75% and specificity was 96%, 98%, 90%. Tendinopathy of the LHBT on oblique sagittal images showed a sensitivity of 93%, 82%, 64%; specificity was 81%, 96%, and 85%. Subluxation of the LHBT was insensitive (36%, 50%, and 64%) but specific (100%, 98%, and 96%)., Conclusion: MR arthrography is accurate in the detection of pulley lesions; the displacement sign, nonvisibility or discontinuity of the SGHL, and tendinopathy of the LHBT on oblique sagittal images are the most accurate criteria for the detection of pulley lesions.

Purpose: The purpose of this study was to determine inter- and intraobserver variability of MR arthrography of the shoulder in the detection and classification of superior labral anterior posterior (SLAP) lesions., Methods: MR arthrograms of 78 patients who underwent MR arthrography before arthroscopy were retrospectively analysed by three blinded readers for the presence and type of SLAP lesions. MR arthrograms were reviewed twice by each reader with a time interval of 4 months between the two readings. Inter- and intraobserver agreement for detection and classification of SLAP lesions were calculated using kappa coefficients., Results: Arthroscopy confirmed 48 SLAP lesions: type I (n = 4), type II (n = 37), type III (n = 3), type IV (n = 4). Sensitivity and specificity for detecting SLAP lesions with MR arthrography for each reader were 88.6%/93.3%, 90.9%/80.0% and 86.4%/76.7%. MR arthrographic and arthroscopic grading were concurrent for 72.7%, 68.2% and 70.5% of SLAP lesions for readers 1-3, respectively. Interobserver agreement was excellent (kappa = 0.82) for detection and substantial (kappa = 0.63) for classification of SLAP lesions. For each reader intraobserver agreement was excellent for detection (kappa = 0.93, kappa = 0.97, kappa = 0.97) and classification (kappa = 0.94, kappa = 0.84, kappa = 0.93) of SLAP lesions., Conclusion: MR arthrography allows reliable and accurate detection of SLAP lesions. In addition, SLAP lesions can be diagnosed and classified with substantial to excellent inter- and intraobserver agreement.

The purpose of the present study was to evaluate the anatomical variability of the superior labrum and to compare the value of MR arthrography and multi-slice CT arthrography in the diagnosis of variants of the labro-bicipital complex. Forty-three human shoulder specimens (age range and mean age at death, 61-89 years and 78.3 years) were examined with the use of MR arthrography and multi-slice CT arthrography prior to joint exploration and macroscopic inspection of the superior labrum and labro-bicipital complex. Two radiologists evaluated MR and CT arthrograms, and the results were compared with macroscopic assessments. Anatomical dissection of all shoulder specimens revealed a sublabral recess in 32/43 (74%) cases. The attachment of the superior labrum was categorised as type 1 in ten (23%) cases, as type 2 in eight (19%), as type 3 in ten (23%), and as type 4 in 14 (33%) cases. One superior labrum showed detachment consistent with a superior labral anteroposterior (SLAP) type 3 lesion. On MR arthrography and CT arthrography the attachment of the superior labrum was categorised in concordance with macroscopic assessments in 79% and 84% of cases, respectively. The anteroposterior extension of sublabral recesses was accurately determined with MR and CT arthrography in 59% and 81% of cases, respectively. The attachment of the superior labrum shows considerable variability. Thus, exact depiction of variants is essential in order to avoid the false positive diagnosis of a superior labral tear (SLAP or Andrews lesion). Both, MR arthrography and multi-slice CT arthrography were effective in the detection and classification of sublabral recesses.

Objective: The purpose of this study was to evaluate the diagnostic performance of MR arthrography in the assessment of superior labral anteroposterior (SLAP) lesions of the shoulder with emphasis on the classification of SLAP lesions., Materials and Methods: Two hundred sixty-five MR arthrograms including 68 MR arthrograms of patients with arthroscopically proven SLAP lesions of the shoulder and 197 MR arthrograms of patients with an intact superior labrum and biceps anchor were retrospectively reviewed in random order. MR arthrography was performed using triplanar T1-weighted spin-echo sequences and a coronal oblique T2-weighted fast spin-echo sequence. MR arthrograms were evaluated by two radiologists with agreement by consensus, and the results were compared with arthroscopic findings., Results: Of 68 SLAP lesions, seven (10%) were arthroscopically classified as type I, 41 (60%) as type II (including 20 type II lesions with coexisting Bankart lesions [29%]), 14 (21%) as type III, and six (9%) as type IV. Compared with arthroscopy as the gold standard, MR arthrography showed a sensitivity of 82% and a specificity of 98% for the overall detection of SLAP lesions. MR arthrographic grading and arthroscopic grading were concurrent in 45 (66%) of 68 arthroscopic diagnoses. Of the surgically confirmed SLAP lesions, involvement of the biceps insertion and SLAP type II lesions with coexisting Bankart lesions were assessed correctly in 75% and 95% of cases, respectively., Conclusion: MR arthrography is a highly effective method for the detection of SLAP lesions, but this technique is limited in the classification of different types of SLAP lesions. However, for preoperative planning MR arthrography provides accurate information about the stability of the biceps insertion and the presence of associated anteroinferior labral injuries.