Advanced MRI Techniques of the Shoulder Joint: Current Applications in Clinical Practice

3-Dimensional (3D) Isotropic MRI of the Shoulder - Advantages Over 2D MRI

The increasing implementation of high-field MRI scanners and the development of novel imaging techniques have rendered 3D imaging of joints more feasible and efficient than ever. This article describes the current state of 3D MRI of the shoulder and highlights the benefits of the technique over conventional 2D MRI with respect to shoulder derangements.

Efficacy of biceps-radial-slice magnetic resonance images for the diagnosis of biceps and pulley lesions

BACKGROUND

Injuries to the biceps reflection pulley lead to instability of the long head of the biceps tendon (LHBT). However, conventional magnetic resonance (MR) imaging (MRI) has low diagnostic accuracy for LHBT and pulley lesions. Here, we investigated the usefulness of novel biceps-radial MRI for evaluating LHBT and pulley lesions.

METHODS

Biceps-radial MR images of 84 patients (84 shoulders) were prospectively analyzed. The biceps-radial MRI protocol includes sequences acquired in radial planes perpendicular to the LHBT in the shoulder joint. All patients underwent shoulder arthroscopy, and the intraoperative LHBT and pulley lesion findings were compared to the preoperative evaluations. The diagnostic accuracies of the biceps-radial MR images and conventional MR images were determined.

RESULTS

A normal LHBT was observed in 30 (31.6%) patients, partial tears in 43 (52.6%), and complete tears in 11 (15.8%). Normal LHBT stability was present in 54 (61.4%) patients, subluxation in 24 (31.6%), and dislocation in 6 (7.0%). The biceps-radial MR (kappa coefficient: 0.94) and conventional MR (kappa coefficient: 0.68) images accurately identified LHBT tears. The biceps-radial MR images excellently agreed with the arthroscopic findings (kappa coefficient: 0.91), whereas the conventional MR images poorly agreed (kappa coefficient: 0.17) regarding LHBT instability. A normal medial wall of the pulley was observed in 26 (31.0%) patients, partial tears in 30 (35.7%), and complete tears in 28 (33.3%). A normal lateral wall of the pulley was observed in 30 (35.7%) patients, partial tears in 21 (25.0%), and complete tears in 33 (39.3%). The biceps-radial MR images excellently agreed with the arthroscopic findings (kappa coefficient: 0.89), whereas the conventional MR images moderately agreed (kappa coefficient: 0.50) regarding medial pulley lesions. The biceps-radial MR images excellently agreed with the arthroscopic findings (kappa coefficient: 0.95) and the conventional MR images moderately agreed (kappa coefficient: 0.56) regarding lateral pulley lesions.

CONCLUSION

Biceps-radial MRI allows for tracking of the LHBT and pulley from the supraglenoid tuberosity to the bicipital groove in the glenohumeral joint and accurate evaluations of LHBT and pulley lesions.

Diagnostic performance of a 3D double-echo steady-state sequence at 3 T using radial reformats for detecting and grading rotator cuff tears: a pilot diagnostic accuracy study with magnetic resonance imaging and arthroscopic correlation

BACKGROUND

In diagnosing rotator cuff tears (RCTs), magnetic resonance imaging (MRI) is the imaging modality of choice, and its accuracy is improving constantly.

PURPOSE

To evaluate the diagnostic performance of a high-resolution 3D double-echo steady-state (DESS) sequence with radial and paracoronal 3-T MRI regarding the grading of RCTs in correlation with conventional 2D MRI and arthroscopic findings.

MATERIAL AND METHODS

We retrospectively compared arthroscopic findings of RCTs with preoperative MRI, including conventional 2D sequences and radial and paracoronal DESS images in 20 patients. Two observers evaluated supraspinatus (SSP), infraspinatus (ISP), and subscapularis (SSC) tendon tears using a grading system. For statistical analysis, arthroscopy was used as the reference standard.

RESULTS

Inter-observer agreement for detecting and grading SSP, ISP, and SSC tendon tears on radial and paracoronal sliced 3D DESS MRI was excellent (intraclass-correlation [ICC] = 0.92-0.98; all P < 0.001). Regarding the detection of SSP lesions, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 93.8%, 50%, 88.2%, and 66.7% for both radial and paracoronal DESS imaging. A sensitivity of 100%, specificity of 61.1%, PPV of 22.2%, and NPV of 100% were noted for detecting ISP tendon tears using radially reformatted DESS images. Regarding detecting SSC tendon tears using radially reformatted DESS images, sensitivity, specificity, PPV, and NPV were 100%, 81.3%, 50%, and 100%, respectively. The results with standard 2D MRI were similar.

CONCLUSION

The DESS technique with radially reformatted images provided excellent sensitivity and high inter-observer agreement in detecting RCTs. It showed a moderate to high correlation between MRI and arthroscopy for diagnosing SSP and SSC tendon tears.

Advantages of the Use of Axial Traction Magnetic Resonance Imaging (MRI) of the Shoulder in Patients with Suspected Rota-Tor Cuff Tears: An Exploratory Pilot Study

Magnetic Resonance Imaging (MRI) with axial traction is a tool for the assessment of musculoskeletal pathology. Previous reports have demonstrated a better distribution of intra-articular contrast material. No investigations were performed to evaluate glenohumeral joint axial traction MRI in patients with suspected rotator cuff tears. This study aims to assess the morphological changes and the potential advantage of glenohumeral joint axial traction MRI without intra-articular contrast administration in patients with suspected rotator cuff tears. Eleven patients with clinical suspicion of rotator cuff tears underwent a shoulder MRI scan with and without axial traction. PD weighted images with SPAIR fat saturation technique and T1 weighted images with TSE technique were acquired in the oblique coronal, oblique sagittal and axial planes. Axial traction allowed a significant widening of the subacromial space (11.1 ± 1.5 mm vs. 11.3 ± 1.8 mm; p = 0.001) and inferior glenohumeral space (8.6 ± 3.8 mm vs. 8.9 ± 2.8 mm; p = 0.029). With axial traction, there was a significant decrease in measurements of the acromial angle (8.3 ± 10.8° vs. 6.4 ± 9.8°; p < 0.001) and gleno-acromial angle (81 ± 12.8° vs. 80.7 ± 11.5°; p = 0.020). Our investigation demonstrates for the first time significant morphological changes in the shoulder of patients with suspected rotator cuff tears who underwent a glenohumeral joint axial traction MRI.

Quality assessment of shoulder MRI according to practice parameters of American College of Radiology: A multi-center study in Jordan

Magnetic resonance imaging (MRI) is essential for assessing shoulder conditions. This study aimed to evaluate current shoulder MRI practices in Jordan, including technical parameter patterns, and determine if they adhere to the American College of Radiology (ACR) guidelines. The retrospective analysis included data from 48 eligible participants from 13 MRI centers in March 2021. Descriptive and correlation data analysis were performed using IBM SPSS statistics version_20 and Excel 2013. Most MRI centers (50%) were private outpatient clinics with closed MRI machines above 1 Tesla. Most participants (62.5%) were male, and shoulder pain (47.9%) was the main clinical indication. Most shoulder orientations (68.7%, 33/48) were right shoulders, and the coronal MRI planes (43%, 121/280) were the most common. The alignment percentage for the axial plane was 100%, but MRI artifacts of the shoulder were present in 8.2% of cases (23/280). Dark fluid T1-W coronal sequence was not conducted in 25% of the cases. The percentage of the field view (FOV) within ACR recommendations was 45% (126/281), and slice thickness parameters were 96% (269/281). The recommended pixel area for all sequences was 47.9% (134/280), encompassing all axial, sagittal oblique, and coronal planes. However, crucial parameters, such as FOV and slice thickness, were inadequate and did not meet the ACR guidelines, resulting in suboptimal image quality of shoulder MRI. To improve MRI image quality, it is recommended that MRI technologists receive ongoing education and training on appropriate MRI image parameters.

Current Understanding and New Advances in the Surgical Management of Reparable Rotator Cuff Tears: A Scoping Review

Rotator cuff (RC) tears are among the most common musculoskeletal disorders and can be associated with pain, weakness, and shoulder dysfunction. In recent years, there have been significant advances with regard to the understanding of rotator cuff disease and its management. With technological improvements and advanced diagnostic modalities, there has been much progress as to improved understanding of the pathology. Similarly, with advanced implant designs and instrumentation, operative techniques have evolved. Furthermore, refinements in postoperative rehabilitation protocols have improved patient outcomes. In this scoping review, we aim to provide an overview of the current knowledge on the treatment of rotator cuff disorders and to highlight recent advances in its management.

Aktuelle Aspekte der Behandlung der Rotatorenmanschette

Rotatorenmanschettenrupturen gehören zu den häufigsten muskuloskeletalen Erkrankungen und können mit ausgeprägten Schmerzen und Funktionseinschränkungen einhergehen. Für ihre Entstehung ist eine Vielzahl von Faktoren relevant, u. a. die individuelle Anatomie des Akromions. Mit Hilfe der heutigen technischen Möglichkeiten wurde nun festgestellt, dass zusätzlich zu seiner lateralen Ausdehnung auch die sagittale Ausdehnung des Akromions eine Rolle zu spielen scheint. Die bildgebende Darstellung der Rotatorenmanschette (RM) hat von den technischen Fortschritten der letzten Jahrzehnte ebenfalls profitiert. Magnetresonanztomographie (MRT) und MR-Arthrographie werden heute flächendeckend eingesetzt. Letztere bietet die höchste Sensitivität für die Entdeckung selbst kleiner Partialläsionen. Neue Sequenzen und Nachbearbeitungsmöglichkeiten können als hilfreiche tools für die operative Planung eingesetzt werden. Grundsätzlich richtet sich die Behandlung der RM neben der Symptomatik nach der Rupturgenese und -morphologie sowie der erwarteten Gewebequalität des Muskel-Sehnen-Kontinuums. Auch das Gesamtprofil, die Erwartungshaltung und die Rehabilitationsmöglichkeiten des Patienten sind wichtig. Die heutigen operativen Techniken werden durch spannende Entwicklungen der Industrie mitbestimmt, die in den letzten Jahren immer bessere Fadenankersysteme, aber auch Augmentationsmaterialien auf den Markt gebracht hat. Letztere zielen nicht nur auf die mechanische Verstärkung der Sehnenrekonstruktion, sondern auch auf die Optimierung der biologischen Eigenschaften des Konstrukts ab. Hinsichtlich Fixation konnte die biomechanische Forschung zeigen, dass zweireihige oder Suture-Bridge-Fixationen einreihigen oder transossären Fixationen überlegen sind. Diese Überlegenheit im Labor spiegelt sich noch nicht klar in den klinischen Ergebnissen wider, dennoch sind die meisten Chirurgen heute auf diese Technik übergegangen. Was die postoperative Nachbehandlung angeht, stellen jüngste randomisiert-kontrollierte Untersuchungen das Konzept der postoperativen Immobilisation in Abduktion in Frage. Hier scheint das letzte Wort noch nicht gesprochen zu sein.

Machine Learning-Based Ultrasomics for Predicting Subacromial Impingement Syndrome Stages

OBJECTIVES

To determine the performance of machine learning (ML)-based ultrasomic analysis of subacromial impingement syndrome (SIS) stage evaluation.

METHODS

In this retrospective study, 324 patients with SIS were included. The SIS stage was evaluated with a Neer test. Regions of the musculi supraspinatus were manually segmented by an experienced radiologist. Then, 5936 ultrasomic features were extracted from the Ultrasomics Platform software. The Wilcoxon test was used to identify differentially expressed radiomic features. Then, these differentially expressed features were submitted to the least absolute shrinkage and selection operator (LASSO) for model construction. The area under the curve (AUC) of the receiver operating characteristic was used to evaluate the performance of the ultrasonic model for SIS stage evaluation.

RESULTS

Finally, a total of 223 early-stage and 101 advanced-stage SIS patients were randomly divided into a training cohort (n = 227) and a validation cohort (n = 97). After feature-dimensionality reduction, a total of 28 radiomic features were submitted to LASSO analysis. Finally, 10 radiomic features were finally included for radiomics model construction. The AUC results showed that the ultrasomics model had moderate performance for SIS stage evaluation in both the training cohort (AUC = 0.839) and the validation cohort (AUC = 0.789).

CONCLUSIONS

ML-derived ultrasomics can discriminate the SIS stage in patients with SIS. This noninvasive and low-cost approach may be helpful in the preliminary screening of shoulder pain.

3D MRI of the Shoulder

Magnetic resonance imaging provides a comprehensive evaluation of the shoulder including the rotator cuff muscles and tendons, glenoid labrum, long head biceps tendon, and glenohumeral and acromioclavicular joint articulations. Most institutions use two-dimensional sequences acquired in all three imaging planes to accurately evaluate the many important structures of the shoulder. Recently, the addition of three-dimensional (3D) acquisitions with 3D reconstructions has become clinically feasible and helped improve our understanding of several important pathologic conditions, allowing us to provide added value for referring clinicians. This article briefly describes techniques used in 3D imaging of the shoulder and discusses applications of these techniques including measuring glenoid bone loss in anterior glenohumeral instability. We also review the literature on routine 3D imaging for the evaluation of common shoulder abnormalities as 3D imaging will likely become more common as imaging software continues to improve.

Automated Brain Region Segmentation for Single Cell Resolution Histological Images Based on Markov Random Field

The brain consists of massive regions with different functions and the precise delineation of brain region boundaries is important for brain region identification and atlas illustration. In this paper we propose a hierarchical Markov random field (MRF) model for brain region segmentation, where a MRF is applied to the downsampled low-resolution images and the result is used to initialize another MRF for the original high-resolution images. A fractional differential feature and a gray level co-occurrence matrix are extracted as the observed vector for the MRF and a new potential energy function, which can capture the spatial characteristic of brain regions, is proposed as well. A fuzzy entropy criterion is used to fine-tune the boundary from the hierarchical MRF model. We test the model both on synthetic images and real histological mouse brain images. The result suggests that the model can accurately identify target regions and even the whole mouse brain outline as a special case. An interesting observation is that the model cannot only segment regions with different cell density but also can segment regions with similar cell density and different cell morphology texture. Thus this model shows great potential for building the high-resolution 3D brain atlas.

Thrower's Shoulder: An Approach to MR Imaging Interpretation

In this article, the authors aim to focus on the challenges of interpreting shoulder MR imaging in the throwing athlete with an approach formed by evidence-based literature and clinical experience, with a particular focus on superior labrum tears.

7-T clinical MRI of the shoulder in patients with suspected lesions of the rotator cuff

Background

To evaluate feasibility and diagnostic performance of clinical 7-T magnetic resonance imaging (MRI) of the shoulder.

Methods

Eight patients with suspected lesions of the rotator cuff underwent 7-T MRI before arthroscopy. Image quality was scored for artifacts, B₁⁺ inhomogeneities, and assessability of anatomical structures. A structured radiological report was compared to arthroscopy. In four patients, a visual comparison with pre-existing 1.5-T examinations was performed.

Results

Regarding image quality, the majority of the sequences reached values above the middle of each scoring scale. Fat-saturated proton density sequences showed least artifacts and best structure assessability. The most homogenous B₁⁺ field was reached with gradient-echo sequences. Arthroscopy did not confirm tendinopathy/partial tear of supraspinatus in 5/8 patients, of subscapularis in 5/6, and of infraspinatus in one patient; only a partial lesion of the subscapularis tendon was missed. Pathologic findings of long bicipital tendon, acromioclavicular joint, glenohumeral cartilage, labrum, and subacromial subdeltoideal bursa were mainly confirmed; exceptions were one lesion of the long bicipital tendon, one subacromial bursitis, and one superior glenoid labrum anterior-to-posterior lesion, missed on 7-T MRI. Evaluating all structures together, sensitivity was 86%, and specificity 74%. A better contrast and higher image resolution was noted in comparison to previous 1.5-T examinations.

Conclusions

7-T MRI of the shoulder with diagnostic image quality is feasible. Overrating of tendon signal alterations was the main limitation. Although the diagnostic performance did not reach the current results of 3-T MRI, our study marks the way to implement clinical 7-T MRI of the shoulder.

Diagnostic performance of shoulder magnetic resonance arthrography for labral tears having surgery as reference: comparison of high-resolution isotropic 3D sequence (THRIVE) with standard protocol

PURPOSE

To compare the diagnostic performance of T1 high-resolution isotropic volume excitation (THRIVE) sequence with that of a standard protocol for direct shoulder magnetic resonance arthrography (MRA) for the diagnosis of superior labral anterior-to-posterior (SLAP) and Bankart lesions, using arthroscopy findings as a reference standard.

MATERIALS AND METHODS

We retrospectively studied 84 patients who underwent direct shoulder 3T MRA using THRIVE and two-dimensional three-plane proton-density fat-suppressed (2D-PD-FS) sequences. One reviewer evaluated the contrast-to-noise ratio (CNR) as a quantitative image quality. Other two reviewers independently evaluated the subjective image noise, image sharpness, and radiologic diagnosis as qualitative image quality. Arthroscopic surgical findings were considered the reference standard. Wilcoxon rank sum, Chi-square/Fisher's exact, and DeLong's tests, as well as intraclass correlation coefficients (ICCs) were used to evaluate differences between THRIVE and 2D-PD-FS images.

RESULTS

THRIVE images had significantly higher CNR (p < 0.001), and subjective ratings of image noise (p = 0.009) and sharpness (p = 0.039) than 2D-PD-FS images (p < 0.001). THRIVE images had similar (p ≥ 0.18) diagnostic performance (sensitivity, 93.0-97.2%; specificity, 95.8-100%; accuracy, 95.2-97.6%) for the diagnosis of SLAP and Bankart lesions with excellent agreement (ICC = 0.898-0.942) when compared to 2D-PD-FS images (sensitivity, 86.1-91.7%; specificity, 93.8-95.8%; accuracy, 90.5-92.9%; agreement, ICC = 0.782-0.858). The scan time was reduced by 69% for THRIVE sequence compared to 2D-PD-FS sequence (2 min 40 s vs. 8 min 40 s).

CONCLUSION

The THRIVE sequence may be helpful in the diagnosis of SLAP and Bankart lesions, and may be routinely used during direct shoulder 3T MRA.