Metabolic patterns of the shoulder joint on (18)F-fluorodeoxyglucose positron emission tomography/computed tomography in adhesive capsulitis

An approach leveraging radiomics and model checking for the automatic early diagnosis of adhesive capsulitis

Adhesive Capsulitis of the shoulder is a painful pathology limiting shoulder movements, commonly known as "Frozen Shoulder". Since this pathology limits movement, it is important to make an early diagnosis. Diagnosing capsulitis relies on clinical assessment, although diagnostic imaging, such as Magnetic Resonance Imaging, can provide predictive or supportive information for specific characteristic signs. However, its diagnosis is not so simple nor so immediate, indeed it remains a difficult topic for many general radiologists and expert musculoskeletal radiologists. This study aims to investigate whether it is possible to use disease signs within a medical image to automatically diagnose Adhesive Capsulitis. To this purpose, we propose an automatic Model Checking-based approach to quickly diagnose the Adhesive Capsulitis taking as input the radiomic feature values from the medical images. Furthermore, we compare the performance achieved by our method with diagnostic results obtained by professional radiologists with different levels of experience. To the best of our knowledge, this is the first method for the automatic diagnosis of Adhesive Capsulitis of the Shoulder.

Metformin improves fibroblast metabolism and ameliorates arthrofibrosis in rats

Background

Emerging studies have suggested an essential role of fibroblast metabolic reprogramming in the pathogenesis of arthrofibrosis. The metabolic modulator metformin appears to be a therapeutic candidate for fibrotic disorders. However, whether metformin could alleviate arthrofibrosis has not been defined. In this study we have determined if treatment with metformin has beneficial effect on arthrofibrosis and its underlying mechanism.

Methods

Articular capsule samples were collected from patients with/without arthrofibrosis to perform gene and protein expression analysis. Arthrofibrosis animal model was established to examine the anti-fibrotic effect of metformin. Cell culture experiments were conducted to determine the mechanism by which metformin inhibits fibroblast activation.

Results

We found that glycolysis was upregulated in human fibrotic articular capsules. In an arthrofibrosis animal model, intra-articular injection of metformin mitigated inflammatory reactions, downregulated expression of both fibrotic and glycolytic markers, improved range of motion (ROM) of the joint, and reduced capsular fibrosis and thickening. At the cellular level, metformin inhibited the activation of fibroblasts and mitigated the abundant influx of glucose into activated fibroblasts. Interestingly, metformin prompted a metabolic shift from oxidative phosphorylation to aerobic glycolysis in activated fibroblasts, resulting in the anti-fibrotic effect of metformin.

Conclusion

Metformin decreased glycolysis, causing a metabolic shift toward aerobic glycolysis in activated fibroblasts and has beneficial effect on the treatment of arthrofibrosis.The translational potential of this article: The findings of this study demonstrated the therapeutic effect of metformin on arthrofibrosis and defined novel targets for the treatment of articular fibrotic disorders.

Shoulder adhesive capsulitis in cancer patients undergoing positron emission tomography - computed tomography and the association with shoulder pain

BACKGROUND

Adhesive capsulitis is a relatively common condition that can develop in cancer patients during treatment. Positron emission tomography - computed tomography (PET-CT) is routinely performed as a follow-up study in cancer patients after therapy. Being aware of PET-CT findings to suggest shoulder adhesive capsulitis may help to alert clinicians for the diagnosis of unsuspected shoulder capsulitis.

AIM

To assess the association of shoulder adhesive capsulitis with cancer/therapy type and symptoms in cancer patients undergoing PET-CT.

METHODS

Our prospective study received Institutional Review Board approval. Written informed consent was obtained from all patients, who answered a questionnaire regarding shoulder pain/stiffness at the time of PET-CT study, between March 2015 and April 2019. Patients with advanced glenohumeral arthrosis, metastatic disease or other mass in the shoulder, or shoulder arthroplasty were excluded. Patterns of shoulder capsule 18F-fluorodeoxyglucose (FDG) uptake were noted. Standard Uptake Value (SUV)max and SUVmean values were measured at rotator interval (RI) and deltoid muscle in bilateral shoulders. Normalized SUV (SUV of RI/SUV of deltoid muscle) was also calculated. We assessed if SUV values are different between symptomatic and asymptomatic patients in both shoulders. Covariates were age, gender, and therapy type (surgery, chemotherapy, radiation). Wilcoxon rank sum tests were used to compare unadjusted marginal differences for age, SUV measurements between symptomatic and asymptomatic patients. Multiple linear regression models were used to examine the relationship between right or left shoulder SUV measurements and symptom status, after adjusting for covariates. Statistical significance level was set at P < 0.05.

RESULTS

Of 252 patients initially enrolled for the study (mean age 66 years, 67 symptomatic), shoulder PET-CT data were obtained in 200 patients (52 were excluded due to exclusion criteria above). The most common cancer types were lymphoma (n = 61), lung (n = 54) and breast (n = 53). No significant difference was noted between symptomatic and asymptomatic patients in terms of age, gender, proportion of patients who had surgical therapy and radiation therapy. A proportion of patients who received chemotherapy was higher in patients who were asymptomatic in the right shoulder compared to those symptomatic in the right shoulder (65% vs 48%, P = 0.012). No such difference was seen for the left shoulder. In both shoulders, SUVmax and SUVmean were higher in symptomatic shoulders than asymptomatic shoulders (Left SUVmax 2.0 vs 1.6, SUVmean 1.6 vs 1.3, both P < 0.002; Right SUVmax 2.2 vs 1.8, SUVmean 1.8 vs 1.5, both P < 0.01). For lung cancer patients, bilateral RI SUVmax and SUVmean values were higher in symptomatic shoulders than asymptomatic shoulders. For other cancer patients, symptomatic patients had higher left RI SUVmax/mean than asymptomatic patients after adjustment.

CONCLUSION

In symptomatic patients metabolic activities in RI were higher than asymptomatic patients. Adhesive capsulitis should be considered in cancer patients with shoulder symptoms and positive FDG uptake in RI.

The role of 18F-FDG PET/CT in the diagnosis of frozen shoulder

PURPOSE

Frozen shoulder is characterized by pain and reduced passive movement capability, and the diagnose is made clinically. However, pain is the major symptom in the first stage before stiffness occurs, and the condition can be mistaken for subacromial impingement. This study explored the possibility to use positron emission tomography/computed tomography (PET/CT) with a ¹⁸F Flour-Deoxy-Glucose (FDG) tracer in the diagnostic process.

METHODS

Eleven patients with frozen shoulder and 9 patients with subacromial impingement received a ¹⁸F-FDG PET/CT scan before being treated surgically. During arthroscopy, the diagnoses were confirmed. Images were blindly analyzed visually by two nuclear medicine physicians. Also, semi-quantified analysis applying a set of standard regions was performed, and standard uptake value in both shoulder regions was recorded.

RESULTS

Both the visual description of the pictures and the semi-quantified analysis generally showed increased FDG uptake in the affected shoulder regions of patients that had frozen shoulder and no uptake in patients with subacromial impingement. Kappa for interobserver agreement in the visual assessments was 0.74. Sensitivity was 92% and specificity 93% of the visual assessment, 77% and 93%, respectively, of the semi-quantified analyses, and by combining the two types of analyses sensitivity was 100% and specificity was 93% for the distinction between frozen shoulders and subacromial impingement/unaffected shoulders.

CONCLUSION

¹⁸F-FDG PET/CT seems to be a valid method to diagnose frozen shoulder. This is clinically relevant in diagnostically challenging cases, for instance in the first phase of frozen shoulder, which can be difficult to distinguish from subacromial impingement.

LEVEL OF EVIDENCE

II.

The puzzling pathophysiology of frozen shoulders - a scoping review

Purpose

The pathophysiology of frozen shoulders is a complex and multifactorial process. The purpose of this review is to scope the currently available knowledge of the pathophysiology of frozen shoulders.

Methods

A systematic search was conducted in Medline, Embase and the Cochrane library. Original articles published between 1994 and October 2020 with a substantial focus on the pathophysiology of frozen shoulders were included.

Results

Out of 827 records, 48 original articles were included for the qualitative synthesis of this review. Glenohumeral capsular biopsies were reported in 30 studies. Fifteen studies investigated were classified as association studies. Three studies investigated the pathophysiology in an animal studies. A state of low grade inflammation, as is associated with diabetes, cardiovascular disease and thyroid disorders, predisposes for the development of frozen shoulder. An early immune response with elevated levels of alarmins and binding to the receptor of advance glycation end products is present at the start of the cascade. Inflammatory cytokines, of which transforming growth factor-β1 has a prominent role, together with mechanical stress stimulates Fibroblast proliferation and differentiation into myofibroblasts. This leads to an imbalance of extracellular matrix turnover resulting in a stiff and thickened glenohumeral capsule with abundance of type III collagen.

Conclusion

This scoping review outlines the complexity of the pathophysiology of frozen shoulder. A comprehensive overview with background information on pathophysiologic mechanisms is given. Leads are provided to progress with research for clinically important prognostic markers and in search for future interventions.

Level of evidence

Level V.

The effectiveness of intra-articular vs subacromial corticosteroid injection for frozen shoulder: Study protocol for a randomized controlled trial

BACKGROUND

Intra-articular (IA) corticosteroid injection is a commonly used therapy for frozen shoulder (FS), but controversy still exists regarding the injection site with the best outcome. This randomized controlled trial is designed to determine whether corticosteroid injection into the subacromial space was not inferior to IA injection in patients with FS.

METHODS

This study will be a single-center, randomized, and double-blinded trial. Sixty patients who meet inclusion criteria will be randomized in a ratio of 1:1 to either subacromial injection or IA injection group. The outcome evaluations will be conducted at 4 time points (baseline, 4, 8, and 12 weeks after the injection) by an independent physical therapist. The primary outcome measure is visual analog scale for pain, whereas the secondary outcomes include Constant score, and shoulder passive range of motion including abduction, forward elevation, external rotation at the side, and internal rotation at the side.

DISCUSSION

This study has limited inclusion and exclusion criteria and a well-controlled intervention. This clinical trial is expected to provide evidence of proper site of corticosteroid injection for the treatment of FS.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5368).

What Imaging-Detected Pathologies Are Associated With Shoulder Symptoms and Their Persistence? A Systematic Literature Review

Objective

Shoulder symptoms are common, and imaging is being increasingly used to help with management. However, the relationship between imaging and symptoms remains unclear. This review aims to understand the relationship between imaging‐detected pathologies, symptoms, and their persistence.

Methods

A systematic review using Medline, EMBASE, Cochrane, and grey literature was conducted to April 2017. The cross‐sectional and longitudinal relationships between imaging‐detected abnormalities and symptoms were analyzed and associations qualitatively characterized by a best‐evidence synthesis based on study design, covariate adjustment, and the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. Modalities included ultrasound, magnetic resonance imaging (MRI), radiographs, positron emission tomography (PET), bone scintigraphy, and computed tomography.

Results

A total of 6,569 abstracts was screened and 56 articles were included. In total, 50 studies did not adjust for covariates and 36 analyzed individual pathologies only. The majority of studies showed conflicting results. There was no significant association between most imaging features and symptoms among high‐quality, cross‐sectional studies. There was low‐quality evidence that enhancement of the joint capsule on MRI and increased uptake on PET were associated with symptoms in adhesive capsulitis. Based on high‐quality longitudinal studies, enlarging rotator cuff tears were associated with an increased incidence of symptoms.

Conclusion

There were conflicting results on the association of imaging features with shoulder symptoms and their persistence. The existing evidence was very low in quality, based on the GRADE methodology. Further high‐quality studies are required to understand the relationship between imaging and shoulder symptoms and to determine the appropriate role of imaging in care pathways.

Ultrasound and PET-CT Correlation in Shoulder Pathology: A 5-Year Retrospective Analysis

PURPOSE

To correlate shoulder ultrasound and radiography with F-FDG PET-CT to establish FDG uptake and therefore range of metabolic activity, as defined by SUV analysis, in various symptomatic shoulder pathologies.

METHODS

Retrospective database query was performed for shoulder ultrasound and PET-CT scans between January 2012 and January 2017. Patients who had both studies within 1 year were included. Age- and sex-matched control patients with PET-CT scans only were also included. Retrospective image review determined shoulder pathology, and F-FDG SUVmax was measured using regions of interest placed at the glenohumeral joint, rotator cuff/bursa, and bicipital groove. Glenohumeral and acromioclavicular osteoarthrosis was assessed by radiography using the Kellgren-Lawrence classification system.

RESULTS

Thirty-three patients had both imaging studies within 1 year. Ten patients (11 cases) were included, ranging in age from 56 to 90 years (mean, 67.9 years). Control subjects were selected among patients receiving PET-CT within 1 week of symptomatic patients. Glenohumeral osteoarthrosis was mild in 3 (27%), moderate in 2 (18%), and severe in 2 (18%). Six full-thickness rotator cuff tears (55%) were identified. SUVmax means were compared between the pathologic and control groups and were significantly higher in the former: glenohumeral joint (1.96 vs 1.32; P = 0.016), rotator cuff/bursa (2.80 vs 2.0; P = 0.005), and bicipital groove (2.19 vs 1.48; P = 0.007). The highest values were seen in full-thickness rotator cuff tear and severe biceps tenosynovitis.

CONCLUSIONS

Increased metabolic activity about the shoulder is associated with a spectrum of rotator cuff, glenohumeral joint, and other soft tissue pathology that can be correlated with diagnostic ultrasound findings.

Focal uptake at the rotator interval or inferior capsule of shoulder on 18F-FDG PET/CT is associated with adhesive capsulitis

OBJECTIVE

To determine if focal increased uptake at the rotator interval (RI) and/or inferior capsule (IC) on¹⁸F-FDG PET/CT ("positive PET") predicts the presence of adhesive capsulitis (AC).

MATERIALS AND METHODS

Three populations were retrospectively examined. Group 1 included 1,137 consecutive ¹⁸F-FDG PET/CT studies and was used to determine the prevalence of focal uptake at the RI or IC. Group 2 included 361 cases from a 10-year period with ¹⁸F-FDG PET/CT and MRI of shoulder performed within 45 days of each other and was used to enrich the study group. Group 3 included 109 randomly selected patients from the same time frame as groups 1 and 2 and was used to generate the control group. The study group consisted of 15 cases from the three groups, which had positive PET findings. PET/CT images were assessed in consensus by two musculoskeletal radiologists. The reference standard for a diagnosis of AC was clinical and was made by review of the medical record by a pain medicine physician.

RESULTS

The prevalence of focal activity at either the RI or IC ("positive PET") was 0.53%. Nine patients had a clinical diagnosis of AC and 15 patients had a positive PET. The sensitivity and specificity of PET for detection of AC was 56% and 87%, respectively. PET/CT had a positive likelihood ratio for AC of 6.3 (95% CI: 2.8-14.6).

CONCLUSIONS

Increased uptake at the RI or IC on PET/CT confers a moderate increase in the likelihood of AC.

Clinical correlation of metabolic parameters on 18F-FDG PET/CT in idiopathic frozen shoulder

Objective

Because positron emission tomography/computed tomography (PET/CT) using fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) can be used to visualize inflammation of the musculoskeletal system, it may help elucidate the pathophysiology of frozen shoulder (FS). The purpose of this study was to characterize the uptake pattern on ¹⁸F-FDG PET/CT in patients with idiopathic FS and to determine if there is a correlation between its metabolic parameters and clinical findings.

Methods

¹⁸F-FDG PET/CT was conducted to 35 patients with unilateral idiopathic FS. Clinical data including pain, functional scores, and passive range of motion (ROM) were collected. Maximum standardized uptake values (SUVmax) were measured at the four regions of interest (ROIs): rotator interval (RI), anterior joint capsule (AJC), axillary recess (AR), and posterior joint capsule (PJC) from the attenuation-corrected axial images.

Results

Mean SUVmax values for four ROIs of the affected shoulder were significantly higher than those of the unaffected shoulder. Mean SUVmax values of RI and AR were significantly higher than those of AJC and PJC and mean SUVmax of AJC was significantly higher than that of PJC in the affected side. Three recognizable patterns of increased uptake were noted: (1) AR dominant type (15 patients); (2) RI dominant type (9 patients); (3) both RI and AR dominant type (11 patients). The SUVmax of AR showed negative correlation with abduction and forward flexion. The SUVmax of RI showed negative correlation with external rotation and internal rotation. The SUVmax of AJC showed negative correlation with all ROMs. However, there was no significant correlation between the SUVmax of PJC and any ROM.

Conclusion

Our study demonstrates that the anterior–inferior capsular portion, including RI and AR, is the main pathologic site of idiopathic FS and reveals significant correlations between ROM and metabolic parameters on ¹⁸F-FDG PET/CT. These results imply that AR and RI lesions are related to elevational limitations and rotational limitations, respectively.

Ultrasonographic Measurement of the Thickness of Axillary Recess Capsule in Healthy Volunteers

Objective

To evaluate the inter-rater and intra-rater reliability of ultrasonographic measurements of axillary recess (AR) thickness in healthy individuals, and to analyze the factors affecting the thickness of the AR capsule.

Methods

We recruited 20 healthy individuals (10 male, 10 female) with a mean age of 37 years (standard deviation ±10). Two physiatrists (an experienced and a novice rater) independently investigated the AR thickness in three rounds. The AR thickness was measured for each individual at three shoulder abduction angles (50°, 70°, and 90°). Intra-class correlation (ICC) coefficients were used to assess the reproducibility of each measurement.

Results

Excellent intra-rater reliability coefficients were observed at the three shoulder abduction angles, in the analysis of both raters. The inter-rater reliability coefficient was also was excellent in both studies. There were significant differences in the AR thickness, according to the angle of shoulder abduction. The AR was thicker at 50° than at 70° and 90° (all p<0.001), and the AR was thicker at 70° than at 90° (p<0.001). Height (r=0.62, p=0.003) and body mass index (r=0.52, p=0.019) were positively correlated with AR thickness. Males had a thicker AR capsule than females at all three angles (all p<0.001).

Conclusion

Ultrasonographic measurements of AR thickness in healthy individuals demonstrate excellent intra-rater and inter-rater reliability. AR thickness may depend on anthropometric variables and position of the shoulder.

Proper site of corticosteroid injection for the treatment of idiopathic frozen shoulder: Results from a randomized trial

OBJECTIVE

The objective is to determine whether corticosteroid injection into the subacromial space was not inferior to intra-articular injection in patients with idiopathic frozen shoulder (FS), and whether combined injections had an additive effect.

METHODS

Patients with idiopathic FS (n=126) were randomly assigned to receive ultrasound-guided intra-articular (IA group), subacromial (SA group), or combined IA and subacromial injections (IA+SA group). All groups received a total dose of 40mg triamcinolone acetonide. The outcome measures included the visual analog scale (VAS) for pain, American Shoulder and Elbow Surgeon (ASES) shoulder score, subjective shoulder value (SSV), and passive range of motion before and at 3, 6, and 12 weeks after treatment.

RESULTS

There was significant effect of time on all measurements such that all measures improved in all groups (P<0.001) during the 12 weeks after treatment. Group-by-time interactions were significant for ASES (P=0.006), VAS (P<0.001), SSV (P=0.03), and internal rotation (P=0.014). Between-group comparisons revealed a significant improvement in the IA (P<0.001) and IA+SA (P<0.001) groups as compared to the SA group. The IA+SA group demonstrated significant improvement in internal rotation as compared to the IA group (P=0.046).

CONCLUSION

The efficacy of corticosteroid injection into the SA space in idiopathic FS was inferior to IA injection up to 12 weeks; however, combination injections had an additive effect on increasing the internal rotation angle. These results indicate that although the glenohumeral joint is a major site in the pathogenesis of idiopathic FS, the SA space may be a contributing site.

Usefulness of 18F-fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Monitoring Adhesive Capsulitis After Breast Cancer Treatment

OBJECTIVES

We aimed to assess the usefulness of F-fluorodeoxyglucose (F-FDG) positron emission tomography-computed tomography (PET/CT) in the monitoring of adhesive capsulitis (AC), a joint problem commonly observed in the upper arm after breast cancer treatment.

METHODS

This retrospective study included 230 patients who underwent F-FDG PET/CT before and after modified radical mastectomy of whom 22 patients were identified as having AC and categorized into 2 groups: with severely and mildly limited range of motion in the shoulder joint. The F-FDG uptake patterns and mean and maximum standardized uptake values (SUVs) were analyzed.

RESULTS

The overall incidence of AC after MRM was 9.57%. The SUVs were significantly higher in patients with severely limited range of motion compared with the other group. There was no association between the SUV and radiotherapy. The F-FDG uptake pattern differed between the groups.

CONCLUSIONS

F-fluorodeoxyglucose PET/CT is useful in evaluating AC after breast cancer treatment.