Magnetic resonance imaging of the shoulder

Shoulder MRI parameters in anticipating anterior shoulder dislocation: Are they a reliable and reproducible tool in clinical practice?

BACKGROUND

Anterior shoulder dislocation (ASD) is a frequently observed musculoskeletal injury that is often encountered in the context of sports activities or as a result of trauma. Several magnetic resonance imaging (MRI) parameters have been previously investigated for the purpose of characterizing the anatomical features, which could potentially be responsible for the episodes of instability. These measurements have the potential to identify patients who are susceptible to dislocation. Consequently, ensuring the reliability and consistency of these measurements is crucial in the diagnosis and the management of athletic or traumatic shoulder injuries.

METHODS

A group of four students, who had no previous experience in reading MRI series, were selected to perform radiographic measurements on specific parameters of MRI scans. These parameters were glenoid version, glenoid depth, glenoid width, humeral head diameter, humeral containing angle, and the ratio of humeral head diameter to glenoid diameter. The four participants conducted two distinct readings on a total of 28 sets of shoulder MRI scans. Simultaneously, the aforementioned measures were assessed by a consultant shoulder surgeon.

RESULTS

A total of 1512 measurements were categorized into nine sets: eight from students' measurements (two per student) and one from the consultant. Intra-rater reliability assessed by the intra-class correlation (ICC) test indicated excellent or good reliability for all parameters (p < 0.05), with glenoid depth showing the highest (0.925) and humeral-containing angles the lowest (0.675) ICC value. Inter-rater correlation, also evaluated using ICC, demonstrated strong correlation (p < 0.05), with glenoid diameter having the highest ICC score (0.935) and glenoid depth the lowest (0.849). Agreement analysis, expressed by Cohen's Kappa test, revealed substantial agreement (p < 0.05) for all parameters, with humeral head diameter having the highest agreement (0.90) and humeral-containing angle the lowest (0.73).

CONCLUSION

In this study, intra- and inter-rater MRI parameters are substantially concordant. Credibility comes from these reliability and agreement analyses' statistical significance. Glenoid diameter and depth are the most reliable intrarater and interrater, respectively. Best agreement was with the humeral-containing angle. These data demonstrate repeatability and clinical relevance.

LEVEL OF EVIDENCE

Level IV.

Evaluation of Shoulder Injuries: A Comparative Study of Imaging by Magnetic Resonance Imaging (MRI) and Magnetic Resonance Arthrography (MRA)

Background

In contrast to the standard shoulder arthroscopy, current radio-diagnostic techniques like magnetic resonance arthrography (MRA), and magnetic resonance imaging (MRI) provide less invasive intricate structural detail of shoulder anatomy.

Objectives

Comparison of efficacy of MRA and MRI for diagnosing suspected rotator cuff injury.

Materials and Methods

Over the course of 4 years (from June 2017 to June 2021), a comparative study, including 100 individuals with suspected rotator cuff pathology, was conducted. For the evaluation of shoulder injuries, the assessment and comparison of MRA and MRI were done in terms of sensitivity (Sn), positive predictive value (PPV), and diagnostic accuracy (DA).

Results

MRI and MRA were positive in 76 (76%) and 98 (98%) patients, respectively. The Sn and PPV of MRI for diagnosing the shoulder injury were 76% and 100%, respectively, whereas the Sn and PPV of MRA were 98% and 100%, respectively. MRA was better than MRI in terms of diagnostic accuracy (98% vs. 76%, P = 0.03).

Conclusion

MRA is a nonsurgical effective method in evaluating and diagnosing rotator cuff injuries in comparison to MRI.

Rotator cuff muscle fibrosis can be assessed using ultrashort echo time magnetization transfer MRI with fat suppression

Muscle degeneration following rotator cuff tendon tearing is characterized by fatty infiltration and fibrosis. While tools exist for the characterization of fat, the ability to noninvasively assess muscle fibrosis is limited. The purpose of this study was to evaluate the capability of quantitative ultrashort echo time T1 (UTE-T1) and UTE magnetization transfer (UTE-MT) mapping with and without fat suppression (FS) for the differentiation of injured and control rotator cuff muscles and for the detection of fibrosis. A rat model of chronic massive rotator cuff tearing (n = 12) was used with tenotomy of the right supraspinatus and infraspinatus tendons and silicone implants to prevent healing. Imaging was performed on a 3-T scanner, and UTE-T1 mapping with and without FS and UTE-MT with and without FS for macromolecular fraction (MMF) mapping was performed. At 20 weeks postinjury, T1 and MMF were measured in the supraspinatus and infraspinatus muscles of the injured and contralateral, internal control sides. Histology was performed and connective tissue fraction (CTF) was measured, defined as the area of collagen-rich extracellular matrix divided by the total muscle area. Paired t-tests and correlation analyses were performed. Significant differences between injured and control sides were found for CTF in the supraspinatus (mean ± SD, 14.5% ± 3.9% vs. 11.3% ± 3.7%, p = 0.01) and infraspinatus (17.0% ± 5.4% vs. 12.5% ± 4.6%, p < 0.01) muscles, as well as for MMF using UTE-MT FS in the supraspinatus (9.7% ± 0.3% vs. 9.5% ± 0.2%, p = 0.04) and infraspinatus (10.9% ± 0.8% vs. 10.1% ± 0.5%, p < 0.01) muscles. No significant differences between sides were evident for T1 without or with FS or for MMF using UTE-MT. Only MMF using UTE-MT FS was significantly correlated with CTF for both supraspinatus (r = 0.46, p = 0.03) and infraspinatus (r = 0.51, p = 0.01) muscles. Fibrosis occurs in rotator cuff muscle degeneration, and the UTE-MT FS technique may be helpful to evaluate the fibrosis component, independent from the fatty infiltration process.

Fast field echo resembling a CT using restricted echo-spacing (FRACTURE) sequence for shoulder joint in normal dogs

Shoulder disease is a common cause of forelimb lameness in dogs. Determining the precise underlying cause of shoulder lameness can be challenging, especially in veterinary practice. Computerized tomography (CT) is often the preferred imaging modality for bone evaluation; however, it uses ionizing radiation and provides limited soft tissue contrast. Conversely, magnetic resonance imaging (MRI) offers excellent soft tissue contrast but has limitations in bone imaging. This study aimed to introduce a new technical innovation that enhances cortical and trabecular bone contrast on MRI, which we refer to as Fast Field Echo Resembling a CT Using Restricted Echo-Spacing (FRACTURE). In this prospective pilot study, we aimed to evaluate the use of FRACTURE, CT, and conventional MRI sequences in assessing the normal canine shoulder using a 3.0 Tesla MRI scanner. Five research beagle dogs were included, and the following pulse sequences were acquired for each dog (1): three-dimensional (3D) FRACTURE, (2) T2-weighted (T2W) images using 3D turbo spin echo (TSE), (3) T1-weighted (T1W) images using 3D TSE, (4) PD-weighted (PDW) images using 3D TSE, and (5) CT. Various parameters, including the delineation of cortical bone (intertubercular groove, greater tubercle, and lesser tubercle), conspicuity of the trabecular bone, shoulder joint visualization, and image quality, were measured for each dog and sequence. In all sequences, the shoulder joint was successfully visualized in all planes with mild motion artifacts. The intertubercular groove was best visualized on CT and FRACTURE. Both the greater and lesser tubercles were easily identified on the CT, FRACTURE, and PDW images. The trabecular pattern scored significantly higher in the CT and FRACTURE images compared to the T1W, T2W, and PDW images. Overall, the visualization of the shoulder joint was excellent in all sequences except for T1W. The use of FRACTURE in combination with conventional MRI sequences holds promise for facilitating not only soft tissue evaluation but also cortical and trabecular bone assessment. The findings from this study in normal dogs can serve as a foundation for further FRACTURE studies in dogs with shoulder diseases.

High-frequency Quantitative Ultrasound Imaging of Human Rotator Cuff Muscles: Assessment of Repeatability and Reproducibility

This study evaluated the repeatability and reproducibility of using high-frequency quantitative ultrasound (QUS) measurement of backscatter coefficient (BSC), grayscale analysis, and gray-level co-occurrence matrix (GLCM) textural analysis, to characterize human rotator cuff muscles. The effects of varying scanner settings across two different operators and two US systems were investigated in a healthy volunteer with normal rotator cuff muscles and a patient with chronic massive rotator cuff injury and substantial muscle degeneration. The results suggest that BSC is a promising method for assessing rotator cuff muscles in both control and pathological subjects, even when operators were free to adjust system settings (depth, level of focus, and time-gain compensation). Measurements were repeatable and reproducible across the different operators and ultrasound imaging platforms. In contrast, grayscale and GLCM analyses were found to be less reliable in this setting, with significant measurement variability. Overall, the repeatability and reproducibility measurements of BSC indicate its potential as a diagnostic tool for rotator cuff muscle evaluation.

High-Resolution Imaging Insights into Shoulder Joint Pain: A Comprehensive Review of Ultrasound and Magnetic Resonance Imaging (MRI)

Shoulder joint pain is a complex and prevalent clinical concern affecting individuals across various ages and lifestyles. This review delves into the pivotal role of high-resolution imaging techniques, namely ultrasound and magnetic resonance imaging (MRI), in the comprehensive assessment and management of shoulder joint pain. We explore the anatomical foundations of the shoulder, common etiologies of pain, and the significance of precise diagnosis. High-resolution imaging facilitates the identification of various shoulder pathologies and is crucial in treatment planning, surgical interventions, and long-term prognosis assessment. We examine emerging technologies, discuss challenges and limitations, and chart potential future developments, emphasizing the ongoing evolution of imaging in this critical healthcare domain. In conclusion, high-resolution imaging is an indispensable tool, continually advancing to meet the diagnostic and therapeutic needs of individuals grappling with shoulder joint pain.

Reconstruction of shoulder MRI using deep learning and compressed sensing: a validation study on healthy volunteers

BACKGROUND

To investigate the potential of combining compressed sensing (CS) and deep learning (DL) for accelerated two-dimensional (2D) and three-dimensional (3D) magnetic resonance imaging (MRI) of the shoulder.

METHODS

Twenty healthy volunteers were examined using at 3-T scanner with a fat-saturated, coronal, 2D proton density-weighted sequence with four acceleration levels (2.3, 4, 6, and 8) and a 3D sequence with three acceleration levels (8, 10, and 13), all accelerated with CS and reconstructed using the conventional algorithm and a new DL-based algorithm (CS-AI). Subjective image quality was evaluated by two blinded readers using 6 criteria on a 5-point Likert scale (overall impression, artifacts, and delineation of the subscapularis tendon, bone, acromioclavicular joint, and glenoid labrum). Objective image quality was measured by calculating signal-to-noise-ratio, contrast-to-noise-ratio, and a structural similarity index measure. All reconstructions were compared to the clinical standard (CS 2D acceleration factor 2.3; CS 3D acceleration factor 8). Additionally, subjective and objective image quality were compared between CS and CS-AI with the same acceleration levels.

RESULTS

Both 2D and 3D sequences reconstructed with CS-AI achieved on average significantly better subjective and objective image quality compared to sequences reconstructed with CS with the same acceleration factor (p ≤ 0.011). Comparing CS-AI to the reference sequences showed that 4-fold acceleration for 2D sequences and 13-fold acceleration for 3D sequences without significant loss of quality (p ≥ 0.058).

CONCLUSIONS

For MRI of the shoulder at 3 T, a DL-based algorithm allowed additional acceleration of acquisition times compared to the conventional approach.

RELEVANCE STATEMENT

The combination of deep-learning and compressed sensing hold the potential for further scan time reduction in 2D and 3D imaging of the shoulder while providing overall better objective and subjective image quality compared to the conventional approach.

TRIAL REGISTRATION

DRKS00024156.

KEY POINTS

• Combination of compressed sensing and deep learning improved image quality and allows for significant acceleration of shoulder MRI. • Deep learning-based algorithm achieved better subjective and objective image quality than conventional compressed sensing. • For shoulder MRI at 3 T, 40% faster image acquisition for 2D sequences and 38% faster image acquisition for 3D sequences may be possible.

Magnetic resonance imaging could precisely define the mean value of tendon thickness in partial rotator cuff tears

PURPOSE

Rotator Cuff (RC) lesions are classified in full-thickness and partial-thickness tears (PTRCTs). To our knowledge, no studies investigated the mean size of shoulder tendons in healthy and PTRCT patients using MRI scans. The aim of the study was to provide data to obtain and compare the mean value of tendon sizes in healthy and PTRCTs groups.

METHODS

From 2014 to 2020, 500 were included in the study. They were divided into two groups: Group 1 (100 subjects) was composed of people positive for partial-thickness rotator cuff tears (PTRCTs), while the 400 subjects in Group 2 were negative for PTRCTs.

RESULTS

Overall, of the patients included in the study, 231 were females and 269 were males. The mean age of the patients was 49 ± 12.7 years. The mean thickness of the supraspinatus tendon (SSP) was 5.7 ± 0.6 mm in Group 1, 5.9 ± 0.6 mm in Group 2 (p < 0.001). The mean length of the ISP tendon was 27.4 ± 3.2 mm in Group 1, 28.3 ± 3.8 mm in Group 2 (p = 0.004). The mean width of the SSP tendon was 17 ± 1.6 mm in Group 1, 17.6 ± 2 mm in Group 2 (p = 0.004). The mean width of the infraspinatus tendon (ISP) tendon was 17.7 ± 1.4 mm in Group 1, 18.3 ± 2.1 mm in Group 2 (p = 0.02).

CONCLUSION

The anatomical data present in this paper may serve as a tool for surgeons to properly manage PTRCTs. The findings of the present study aimed to set the first step towards reaching unanimity to establish international cut-off values to perform surgery. Additionally, they could widely increase diagnostic accuracy, improving both conservative and surgical approaches. Lastly, further clinical trials using more accurate diagnostic MRI tools are required to better define the anatomical differences between PTRCT and healthy patients.

LEVEL OF EVIDENCE

Level II, Retrospective Comparative Trial.

The Spectrum of Shoulder Pathologies on Magnetic Resonance Imaging: A Pictorial Review

Patients present to the orthopedic outpatient department with complaints of shoulder pain on movement or restriction of movement in the shoulder joint and are referred for magnetic resonance imaging (MRI) of the shoulder joint. Almost all the patients have similar complaints but may have a wide range of pathology affecting the joint and causing pain. Rotator cuff tears or tendinopathy are the most common causes of shoulder pain. Ultrasound (USG) and MRI are the most commonly used imaging modalities for assessing rotator cuff pathologies. There is a wide range of pathologies affecting the shoulder joint, other than rotator cuff tendinopathies or tears, for which USG is less sensitive and specific in detecting accurate pathology. MRI is the choice of imaging for shoulder joint pathologies. We present a pictorial review discussing and depicting MRI features of a wide list of pathologies of the shoulder joint complex that should be kept in mind when the patient presents with shoulder pain.

High-accuracy detection of supraspinatus fatty infiltration in shoulder MRI using convolutional neural network algorithms

Background

The supraspinatus muscle fatty infiltration (SMFI) is a crucial MRI shoulder finding to determine the patient's prognosis. Clinicians have used the Goutallier classification to diagnose it. Deep learning algorithms have been demonstrated to have higher accuracy than traditional methods.

Aim

To train convolutional neural network models to categorize the SMFI as a binary diagnosis based on Goutallier's classification using shoulder MRIs.

Methods

A retrospective study was performed. MRI and medical records from patients with SMFI diagnosis from January 1st, 2019, to September 20th, 2020, were selected. 900 T2-weighted, Y-view shoulder MRIs were evaluated. The supraspinatus fossa was automatically cropped using segmentation masks. A balancing technique was implemented. Five binary classification classes were developed into two as follows, A: 0, 1 v/s 3, 4; B: 0, 1 v/s 2, 3, 4; C: 0, 1 v/s 2; D: 0, 1, 2, v/s 3, 4; E: 2 v/s 3, 4. The VGG-19, ResNet-50, and Inception-v3 architectures were trained as backbone classifiers. An average of three 10-fold cross-validation processes were developed to evaluate model performance. AU-ROC, sensitivity, and specificity with 95% confidence intervals were used.

Results

Overall, 606 shoulders MRIs were analyzed. The Goutallier distribution was presented as follows: 0 = 403; 1 = 114; 2 = 51; 3 = 24; 4 = 14. Case A, VGG-19 model demonstrated an AU-ROC of 0.991 ± 0.003 (accuracy, 0.973 ± 0.006; sensitivity, 0.947 ± 0.039; specificity, 0.975 ± 0.006). B, VGG-19, 0.961 ± 0.013 (0.925 ± 0.010; 0.847 ± 0.041; 0.939 ± 0.011). C, VGG-19, 0.935 ± 0.022 (0.900 ± 0.015; 0.750 ± 0.078; 0.914 ± 0.014). D, VGG-19, 0.977 ± 0.007 (0.942 ± 0.012; 0.925 ± 0.056; 0.942 ± 0.013). E, VGG-19, 0.861 ± 0.050 (0.779 ± 0.054; 0.706 ± 0.088; 0.831 ± 0.061).

Conclusion

Convolutional neural network models demonstrated high accuracy in MRIs SMFI diagnosis.

Update on Shoulder Arthroplasties with Emphasis on Imaging

Shoulder pain and dysfunction may significantly impact quality of life. If conservative measures fail, advanced disease is frequently treated with shoulder arthroplasty, which is currently the third most common joint replacement surgery following the hip and knee. The main indications for shoulder arthroplasty include primary osteoarthritis, post-traumatic arthritis, inflammatory arthritis, osteonecrosis, proximal humeral fracture sequelae, severely dislocated proximal humeral fractures, and advanced rotator cuff disease. Several types of anatomic arthroplasties are available, such as humeral head resurfacing and hemiarthroplasties, as well as total anatomic arthroplasties. Reverse total shoulder arthroplasties, which reverse the normal ball-and-socket geometry of the shoulder, are also available. Each of these arthroplasty types has specific indications and unique complications in addition to general hardware-related or surgery-related complications. Imaging-including radiography, ultrasonography, computed tomography, magnetic resonance imaging, and, occasionally, nuclear medicine imaging-has a key role in the initial pre-operative evaluation for shoulder arthroplasty, as well as in post-surgical follow-up. This review paper aims to discuss important pre-operative imaging considerations, including rotator cuff evaluation, glenoid morphology, and glenoid version, as well as to review post-operative imaging of the various types of shoulder arthroplasties, to include normal post-operative appearances as well as imaging findings of complications.

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.

Musculoskeletal Manifestations of COVID-19: Currently Described Clinical Symptoms and Multimodality Imaging Findings

COVID-19, the clinical syndrome produced by infection with SARS-CoV-2, can result in multisystem organ dysfunction, including respiratory failure and hypercoagulability, which can lead to critical illness and death. Musculoskeletal (MSK) manifestations of COVID-19 are common but have been relatively underreported, possibly because of the severity of manifestations in other organ systems. Additionally, patients who have undergone sedation and who are critically ill are often unable to alert clinicians of their MSK symptoms. Furthermore, some therapeutic measures such as medications and vaccinations can worsen existing MSK symptoms or cause additional symptoms. Symptoms may persist or occur months after the initial infection, known as post-COVID condition or long COVID. As the global experience with COVID-19 and the vaccination effort increases, certain patterns of MSK disease involving the bones, muscles, peripheral nerves, blood vessels, and joints have emerged, many of which are likely related to a hyperinflammatory host response, prothrombotic state, or therapeutic efforts rather than direct viral toxicity. Imaging findings for various COVID-19–related MSK pathologic conditions across a variety of modalities are being recognized, which can be helpful for diagnosis, treatment guidance, and follow-up.

The online slide presentation from the RSNA Annual Meeting is available for this article.

^©RSNA, 2022

3D MRI with CT-like bone contrast - An overview of current approaches and practical clinical implementation

CT is the imaging modality of choice for assessment of 3D bony morphology but incurs the penalty of ionizing radiation. Improving the ability of 3D MRI to provide high-resolution images of cortical bone with CT-like bone contrast has been a focus of recent research. The ability of 3D MRI to deliver cortical bone information with similar diagnostic performance to CT would complement assessment of soft tissues and medullary bone from a single MRI examination, simplifying evaluation and obviating radiation exposure from additional CT. This article presents an overview of current 3D MRI approaches for imaging cortical bone with CT-like bone contrast including ultrashort echo time, zero echo time, T1-weighted gradient recalled echo, susceptibility-weighted imaging and deep learning techniques. We also discuss clinical implementation of an optimized stack-of-stars 3D gradient recalled echo pulse sequence (3D-Bone) on commercially available MRI scanners for rendering 3D MRI with CT-like bone contrast in our institutional practice.