Muscle involvement in systemic lupus erythematosus: multimodal ultrasound assessment and relationship with physical performance

Physical Performance in a Diverse, Population-Based Cohort of Individuals With Systemic Lupus Erythematosus

OBJECTIVE

To report the burden and correlates of poor physical performance in a diverse cohort of individuals with systemic lupus erythematosus (SLE).

METHODS

In this single-visit study of 446 individuals with SLE from a population-based metropolitan Atlanta cohort, we measured physical performance via the Short Physical Performance Battery (score range 0-12; intermediate-low [<10] vs high [≥10]). We also collected demographic, clinical, and psychosocial variables and examined the associations (adjusted odds ratios [aORs]) of intermediate-low versus high physical performance with these characteristics via multivariable logistic regression.

RESULTS

We found that more than half (59.6%) of our participants had poorer (intermediate-low) overall physical performance. Only 7% of the cohort received the maximum score on the lower body strength task versus 90% and 76% receiving the maximum scores on balance and gait speed tasks. Current employment status (aOR 0.69, 95% confidence interval [CI] 0.45-1.05) and higher cognitive functioning (aOR 0.57, 95% CI 0.42-0.77) were strongly associated with lower odds of intermediate-low physical performance. Higher body mass index (aOR 1.25, 95% CI 1.01-1.56), disease activity (aOR 1.59, 95% CI 1.27-1.98), and disease burden (aOR 1.38, 95% CI 1.08-1.77) were associated with poorer performance, as were higher depressive symptoms, perceived stress scores, and lower educational attainment (not statistically significant).

CONCLUSION

In our population-based, primarily Black cohort, we found that individuals with SLE commonly had poor physical performance. We identified both SLE- and non-SLE-specific factors that could help clinicians identify those most at risk for poor physical performance and intervene to improve, maintain, and support physical performance among those with SLE.

Update on muscle imaging in myositis

PURPOSE OF REVIEW

Imaging techniques such as MRI, ultrasound and PET/computed tomography (CT) have roles in the detection, diagnosis and management of myositis or idiopathic inflammatory myopathy (IIM). Imaging research has also provided valuable knowledge in the understanding of the pathology of IIM. This review explores the latest advancements of these imaging modalities in IIM.

RECENT FINDINGS

Recent advancements in imaging of IIM have seen a shift away from manual and qualitative analysis of the images. Quantitative MRI provides more objective, and potentially more sensitive characterization of fat infiltration and inflammation in muscles. In addition to B-mode ultrasound changes, shearwave elastography offers a new dimension to investigating IIM. PET/CT has the added advantage of including IIM-associated findings such as malignancies.

SUMMARY

It is evident that MRI, ultrasound and PET/CT have important roles in myositis. Continued technological advancement and a quest for more sophisticated applications help drive innovation; this has especially been so of machine learning/deep learning using artificial intelligence and the developing promise of texture analysis.

Multimodal ultrasound muscle assessment in patients with rheumatic diseases: a patient-based reliability study

Objectives

The aim was to explore the inter-reliability of a newly developed US scanning protocol (multimodal US) for the assessment of different aspects of sarcopenia-related muscle involvement, including muscle mass, muscle quality and muscle stiffness [using point shear-wave elastography (SWE)], in patients with rheumatic and musculoskeletal diseases (RMDs).

Methods

Quadriceps muscle mass (i.e. muscle thickness), muscle quality (i.e. muscle echogenicity evaluated with both a visual semi-quantitative scale and a dedicated software package for image analysis, ImageJ) and point SWE measurements were obtained by two rheumatologists (blinded to each other's evaluation) in consecutive RMD patients without previous/current myositis or neuromuscular disorders.Inter-reliability was assessed using the intraclass correlation coefficient (ICC) for continuous variables and Cohen's kappa (κ) for categorical variables.

Results

A total of 45 RMD patients were enrolled [mean age 54.5 (16.0) years, male-to-female ratio 1:1.5, mean BMI 24.6 (4.6) kg/m2], 10 with PsA, 7 RA, 5 AS, 5 PMR, 4 SLE, 4 gout, 4 OA, 3 FM and 3 SSc. The grade of inter-rater reliability was excellent for muscle mass [ICC = 0.969 (0.953 < ICC < 0.979)]. Regarding muscle echogenicity, the agreement was substantial/almost perfect using the visual semi-quantitative scale (weighted linear = 0.793, weighted squared = 0.878) and excellent using ImageJ analysis [ICC = 0.916 (0.876 < ICC < 0.944)]. Finally, a good agreement was obtained for point SWE measurements [ICC = 0.76 (0.712 < ICC < 0.8)].

Conclusion

Multimodal US is a novel and reliable tool for the evaluation of different aspects of muscle involvement (muscle mass, muscle quality and muscle stiffness) in RMD patients.

Quantification of sarcopenia in patients with rheumatoid arthritis by measuring the cross-sectional area of the thigh muscles with magnetic resonance imaging

PURPOSE

To determine the utility of cross-sectional area (CSA) measurements on magnetic resonance imaging (MRI), at the level of the thigh muscles, to estimate muscle mass in discriminating rheumatoid arthritis (RA) patients with sarcopenia from those without.

MATERIALS AND METHODS

Consecutive female RA patients were enrolled for this cross-sectional study. Patients were assessed for disease activity, radiological damage, handgrip strength, physical performance and for the presence of sarcopenia, identified in accordance with the EWGSOP2 criteria. A 1.5 T MRI machine was used to scan the thigh muscles. A dimensional region growth algorithm (Horos™) was used to segment the muscles CSAs (in cm²) on MR images located 25 cm above the knee joint (MRI-CSA-25). The MRI-CSA-25 was obtained by summing the CSAs of the individual muscles. MRI-CSA-25 was correlated (Pearson's r) with the other variables, and its optimal cut-off point (Youden index) for sarcopenia diagnosis was identified in relation to the EWGSOP2 criteria.

RESULTS

32 RA female patients were studied, 34.4% diagnosed as sarcopenic. The mean MRI-CSA-25 was 151.00 cm² for patient with sarcopenia, 275.57 cm² for patient without sarcopenia (p < 0.001). MRI-CSA-25 correlated significantly with measures of physical performance, and disease activity, but not with radiological damage or age. The MRI-CSA-25 optimal cut-off point in discriminating sarcopenic patients was identified at 182.00 cm² (AUC-ROC = 0.894).

CONCLUSION

MRI-CSA-25 can differentiate sarcopenic versus non-sarcopenic RA patients, representing an imaging biomarker of this condition.

Reliability assessment of ultrasound muscle echogenicity in patients with rheumatic diseases: Results of a multicenter international web-based study

Objectives

To investigate the inter/intra-reliability of ultrasound (US) muscle echogenicity in patients with rheumatic diseases.

Methods

Forty-two rheumatologists and 2 radiologists from 13 countries were asked to assess US muscle echogenicity of quadriceps muscle in 80 static images and 20 clips from 64 patients with different rheumatic diseases and 8 healthy subjects. Two visual scales were evaluated, a visual semi-quantitative scale (0-3) and a continuous quantitative measurement ("VAS echogenicity," 0-100). The same assessment was repeated to calculate intra-observer reliability. US muscle echogenicity was also calculated by an independent research assistant using a software for the analysis of scientific images (ImageJ). Inter and intra reliabilities were assessed by means of prevalence-adjusted bias-adjusted Kappa (PABAK), intraclass correlation coefficient (ICC) and correlations through Kendall's Tau and Pearson's Rho coefficients.

Results

The semi-quantitative scale showed a moderate inter-reliability [PABAK = 0.58 (0.57-0.59)] and a substantial intra-reliability [PABAK = 0.71 (0.68-0.73)]. The lowest inter and intra-reliability results were obtained for the intermediate grades (i.e., grade 1 and 2) of the semi-quantitative scale. "VAS echogenicity" showed a high reliability both in the inter-observer [ICC = 0.80 (0.75-0.85)] and intra-observer [ICC = 0.88 (0.88-0.89)] evaluations. A substantial association was found between the participants assessment of the semi-quantitative scale and "VAS echogenicity" [ICC = 0.52 (0.50-0.54)]. The correlation between these two visual scales and ImageJ analysis was high (tau = 0.76 and rho = 0.89, respectively).

Conclusion

The results of this large, multicenter study highlighted the overall good inter and intra-reliability of the US assessment of muscle echogenicity in patients with different rheumatic diseases.

Ultrasound and magnetic resonance imaging as diagnostic tools for sarcopenia in immune-mediated rheumatic diseases (IMRDs)

Sarcopenia is characterized by loss of muscle mass, altered muscle composition, fat and fibrous tissue infiltration, and abnormal innervation, especially in older individuals with immune-mediated rheumatic diseases (IMRDs). Several techniques for measuring muscle mass, strength, and performance have emerged in recent decades. The portable dynamometer and gait speed represent the most frequently used tools for the evaluation of muscle strength and physical efficiency, respectively. Aside from dual-energy, X-ray, absorptiometry, and bioelectrical impedance analysis, ultrasound (US) and magnetic resonance imaging (MRI) techniques appear to have a potential role in evaluating muscle mass and composition. US and MRI have been shown to accurately identify sarcopenic biomarkers such as inflammation (edema), fatty infiltration (myosteatosis), alterations in muscle fibers, and muscular atrophy in patients with IMRDs. US is a low-cost, easy-to-use, and safe imaging method for assessing muscle mass, quality, architecture, and biomechanical function. This review summarizes the evidence for using US and MRI to assess sarcopenia.

Update on Current Imaging of Systemic Lupus Erythematous in Adults and Juveniles

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple organs and organ systems. Musculoskeletal (MSK) involvement is one of the most frequent and the earliest locations of disease. This disease affects joints and periarticular soft tissues, tendon sheaths and tendons, bones, and muscles. Multimodality imaging, including radiography, ultrasound (US), and magnetic resonance imaging (MRI), plays a significant role in the initial evaluation and treatment follow up of MSK manifestations of the SLE. In this paper, we illustrate MSK imaging features in three clinical forms of SLE, including nondeforming nonerosive arthritis, deforming nonerosive arthropathy, and erosive arthropathy, as well as the other complications and features of SLE within the MSK system in adults and juveniles. Advances in imaging are included. Conventional radiography primarily shows late skeletal lesions, whereas the US and MRI are valuable in the diagnosis of the early inflammatory changes of the soft tissues and bone marrow, as well as late skeletal manifestations. In nondeforming nonerosive arthritis, US and MRI show effusions, synovial and/or tenosynovial hypertrophy, and vascularity, whereas radiographs are normal. Deforming arthritis clinically resembles that observed in rheumatoid arthritis, but it is reversible, and US and MRI show features of inflammation of periarticular soft tissues (capsule, ligaments, and tendons) without the pannus and destruction classically observed in RA. Erosions are rarely seen, and this form of disease is called rhupus syndrome.