The longitudinal study of muscle changes with ultrasound: differential changes in idiopathic inflammatory myopathy subgroups.

OBJECTIVES: We investigated shear wave elastography (SWE), B mode US and power Doppler (PDUS) as imaging biomarkers for longitudinal follow-up in idiopathic inflammatory myopathy (IIM), with a particular focus on immune-mediated necrotizing myopathy (IMNM) and DM. METHODS: Participants had serial SWE, PDUS on the deltoid (D) and vastus lateralis (VL) muscles on four occasions at intervals of 3-6 months. Clinical assessments included manual muscle testing, and patient- and physician-reported outcome scales. RESULTS: Thirty-three participants were included: IMNM = 17, DM = 12, overlap myositis = 3, PM = 1. Twenty were in a prevalent clinic group, and 13 were recently treated cases in an incident group. Differential changes in SWS and US domains occurred with time in both the prevalent and incident groups. In the VL-prevalent subgroup, echogenicity increased over time (P = 0.040), while in the incident cases there was a trend for reduction to normal over time (P = 0.097) with treatment. Muscle bulk reduced in the D-prevalent subgroup over time (P = 0.096), suggesting atrophy. SWS also reduced in the VL-incident subgroup over time (P = 0.096), suggesting a trend towards improvement in muscle stiffness with treatment. CONCLUSION: SWE and US appear promising as imaging biomarkers for patient follow-up in IIM and indicate changes over time, especially with echogenicity, muscle bulk and SWS in the VL. Due to the limitations of the participant numbers, additional studies with a larger cohort are needed to help evaluate these US domains further and outline specific characteristics within the IIM subgroups.

Advances in the diagnosis of myocarditis in idiopathic inflammatory myopathies: an overview of diagnostic tests.

Cardiac involvement in idiopathic inflammatory myopathies (IIM) purports to worse clinical outcomes, and therefore early identification is important. Research has focused on blood biomarkers and basic investigations such as ECG and echocardiography, which have the advantage of wide availability and low cost but are limited in their sensitivity and specificity. Imaging the myocardium to directly look for inflammation and scarring has therefore been explored, with a number of new methods for doing this gaining wider research interest and clinical availability. Cardiovascular magnetic resonance (CMR) with contemporary multiparametric mapping techniques and late gadolinium enhancement imaging, is an extremely valuable and increasingly used non-invasive imaging modality for the diagnosis of myocarditis. The recently updated CMR-based Lake Louise Criteria for the diagnosis of myocarditis incorporate the newer T1 and T2 mapping techniques, which have greatly improved the diagnostic accuracy for IIM myocarditis.18F-FDG-PET/CT is a well-utilized imaging modality in the diagnosis of malignancies in IIM, and it also has a role for the diagnosis of myocarditis in multiple systemic inflammatory diseases. Endomyocardial biopsy, however, remains the gold standard technique for the diagnosis of myocarditis and is necessary for the diagnosis of specific cases of myocarditis. This article provides an overview of the important tests and imaging modalities that clinicians should consider when faced with an IIM patient with potential myocarditis.

Magnetic resonance imaging patterns revealing muscle pathology and clinical features in idiopathic inflammatory myopathies.

OBJECTIVE: Idiopathic inflammatory myopathies (IIMs) are autoimmune disorders significantly impacting skeletal muscles; however, the precise correlation between muscle magnetic resonance imaging (MRI) findings, muscle pathology, disease subtypes and clinical characteristics remains uncertain. Thus, we investigated the association of muscle MRI findings in IIMs with muscle pathology and clinical features. METHODS: New-onset IIM patients underwent proximal upper and/or lower limb muscle MRI. Patterns of muscle oedema on MRI were categorised into fascial, honeycomb, peripheral, foggy, dense, or coarse dot patterns and compared with inflammatory cell infiltration sites in corresponding muscle biopsies. The incidence of MRI patterns was examined in patient subgroups using myositis-specific antibodies (MSAs) and 2017 EULAR/ACR classification criteria. Univariate and multivariate analyses were conducted to determine the odds ratios (ORs) of MRI findings for clinical characteristics. RESULTS: Fifty-six of 85 patients underwent muscle biopsy. Foggy, honeycomb and fascial patterns at biopsy sites correlated with inflammatory cell infiltration in the endomysium (OR 11.9, P = 0.005), perimysium (OR 6.0, P = 0.014) and fascia (OR 16.9, P < 0.001), respectively. Honeycomb and foggy patterns were characteristic of patients with anti-TIF1γ or anti-Mi2 antibodies and MSA-negative dermatomyositis, and those with anti-SRP or anti-HMGCR antibodies and MSA-negative polymyositis (PM), respectively. The honeycomb pattern positively correlated with malignancy (OR 6.87, P < 0.001) and Gottron sign (OR 8.05, P = 0.002); the foggy pattern correlated with muscle weakness (OR 11.24, P = 0.005). The dense dot pattern was associated with dysphagia (OR 6.27, P = 0.006) and malignancy (OR 8.49, P = 0.002). CONCLUSION: Muscle MRI holds promise in predicting muscle pathology, disease subtypes and clinical manifestations of IIMs.

The value of non-enhanced MRI in the evaluation of patients with suspected idiopathic inflammatory myopathy.

INTRODUCTION/AIMS: The performance of magnetic resonance imaging (MRI) for diagnosing suspected idiopathic inflammatory myopathy (IIM) remains controversial. Furthermore, the role of contrast-enhanced magnetic resonance imaging (CE-MRI) sequences is unclear. The aim of this study was to evaluate the sensitivity and specificity of a non-enhanced magnetic resonance imaging (NE-MRI) protocol compared to a CE-MRI protocol in adult patients with confirmed IIM. METHODS: This study retrospectively enrolled patients with suspected IIM who underwent MRI of the upper thigh between 2008 and 2020. The protocol consisted of a T1-weighted (T1w) sequence, a turbo inversion recovery magnitude (TIRM) sequence and a contrast-enhanced T1-weighted sequence (CE-T1w). After randomly stratifying patients into a group with only the T1w and TIRM sequences available and another group with additional availability of CE-T1w, three blinded readers assessed the presence of IIM based on characteristic imaging features. Confirmation of the diagnosis was determined based on the 2017 ACR/EULAR criteria. RESULTS: Of the 80 patients (mean age 49.0 ± 21.1 years; 42 female, 38 male) included, 54 (67.5%) had a positive diagnosis of IIM. Cumulated sensitivity and specificity for MRI to detect IIM was 87.1% and 83.3% in the NE-MRI group versus 87.0% and 63.0% in the CE-MRI group. The group differences for sensitivity and specificity were non-significant for each of the three readers, respectively (p ≥ .081). DISCUSSION: NE-MRI detects suspected IIM with high diagnostic accuracy and performs equivalently to CE-MRI. Therefore, it may be appropriate to omit the use of contrast agents in MRI scans performed for suspected IIM.

Evaluating disease status in idiopathic inflammatory myopathies with quantitative muscle ultrasound.

INTRODUCTION/AIMS: Muscle strength, functional status, and muscle enzymes are conventionally used to evaluate disease status in idiopathic inflammatory myopathies (IIM). This study aims to investigate the role of quantitative muscle ultrasound in evaluating disease status in IIM patients. METHODS: Patients with IIM, excluding inclusion body myositis, were recruited along with age- and sex-matched healthy controls (HC). All participants underwent muscle ultrasound and clinical assessments. Six limb muscles were unilaterally scanned using a standardized protocol, measuring muscle thickness (MT) and echo intensity (EI). Results were compared with HC, and correlations were made with outcome measures. RESULTS: Twenty IIM patients and 24 HC were recruited. The subtypes of IIM were dermatomyositis (6), necrotizing myositis (6), polymyositis (3), antisynthetase syndrome (3), and nonspecific myositis (2). Mean disease duration was 8.7 ± 6.9 years. There were no significant differences in demographics and anthropometrics between patients and controls. MT of rectus femoris in IIM patients was significantly lower than HC. Muscle EI of biceps brachii and vastus medialis in IIM patients were higher than HC. There were moderate correlations between MT of rectus femoris and modified Rankin Scale, Physician Global Activity Assessment, and Health Assessment Questionnaire, as well as between EI of biceps brachii and Manual Muscle Testing-8. DISCUSSION: Muscle ultrasound can detect proximal muscle atrophy and hyperechogenicity in patients with IIM. The findings correlate with clinical outcome measures, making it a potential tool for evaluating disease activity of patients with IIM in the late phase of the disease.

Subclinical myocardial involvement in a cohort of patients with antisynthetase syndrome.

OBJECTIVES: There is an increasing interest in knowing whether patients with antisynthetase syndrome (ASSD) may have silent myocardial interstitial involvement. Mapping techniques in cardiac magnetic resonance (CMR) can detect subclinical myocardial involvement. The purpose of this study was to identify alterations in multiparametric CMR in ASSD patients without overt cardiac involvement. METHODS: Patients diagnosed with ASSD underwent a CMR along with the standard clinical workup, investigation of specific and associated myositis antibodies, and high-resolution chest CT. The CMR protocol includes routine morphologic, functional, and late gadolinium enhancement sequences in standard cardiac planes, as well as native T1 and T2 mapping sequences and extracellular volume (ECV) calculation. RESULTS: Twenty-five patients were included in this study (56% women; median age 56.3 years). Three patients were considered in the acute phase at the time of inclusion. Eight patients (32%) showed pathological findings in CMR (6 stable disease, 2 acute phase). Elevated T1, T2 and ECV mapping values were found in 20% (5/25), 17% (4/25) and 24% (6/25) of the group, respectively. Two patients in the acute phase had increased values of both T2 and ECV. CONCLUSIONS: Subclinical myocardial involvement in ASSD is not rare (32%) although its clinical significance is uncertain. Myocardial oedema (T2) was the most frequent finding, followed by increased T1 and/or ECV values likely signalling interstitial fibrosis. Of note, patients in the acute phase showed elevated T2 values.

Myositis and Its Mimics: Guideline Updates, MRI Characteristics, and New Horizons.

Myositis is defined as inflammation within skeletal muscle and is a subcategory of myopathy, which is more broadly defined as any disorder affecting skeletal muscle. Myositis may be encountered as a component of autoimmune and connective tissue diseases, where it is described as idiopathic inflammatory myopathy (IIM). Myositis can also be caused by infections as well as toxins and drugs, including newer classes of medications. MRI plays an important role in the diagnosis and evaluation of patients with suspected myositis, but many entities may have imaging features similar to those of myositis and can be considered myositis mimics. These include muscular dystrophies, denervation, deep venous thrombosis, diabetic myonecrosis, muscle injury, heterotopic ossification, and even neoplasms. In patients with suspected myositis, definitive diagnosis may require integrated analysis of imaging findings with clinical, laboratory, and pathology data. The objectives of this article are to review the fundamental features of myositis, including recent updates in terminology and consensus guidelines for IIMs; the most important MRI differential diagnostic considerations for myositis (i.e., myositis mimics); and new horizons, including the potential importance of artificial intelligence and multimodal integrated diagnostics in the evaluation of patients with muscle disorders.

Quantification of left atrial strain in patients with idiopathic inflammatory myopathy using cardiovascular magnetic resonance feature tracking.

BACKGROUND: Left atrial (LA) dysfunction is involved in idiopathic inflammatory myopathy (IIM). Multiparametric cardiovascular magnetic resonance (CMR) strain imaging is a feasible and reproducible tool for examining global and regional LA functions, as well as left ventricular (LV) function in IIM patients. AIM: The aim of this study was to evaluate the feasibility and reproducibility of LA strain occurrence and strain rate for LA function assessment using CMR in IIM cases. MATERIALS AND METHODS: A total of 36 IIM and 42 healthy control cases were included. Baseline ventricular function was comparatively assessed in both groups. LA strain occurrence and strain rate were examined by cine cardiac magnetic resonance imaging [MRI] utilizing an in-house semiautomated technique. LA global function indexes were quantitated, including reservoir, conduit, and booster-pump functions. RESULTS: A total of 78 participants were enrolled in this study. There was no significant difference in left/right ventricular routine functions between IIM patients and control individuals (p>0.05); the same results (p>0.05) was also observed between patients with high hs-cTnI and normal. However, LV mass index had significant difference (p1=0.003, p2<0.01). Compared with IIM patients and control individuals, only total strain (εs) (p4=0.046) and passive strain (εe) (p4=0.002) showed significant difference, and in cases with high hs-cTnI and normal hs-cTnI, there are differences for εs (p3=0.012) and εe (p4=0.047). The strongest association was found between εe and LV ejection fraction (LVEF) (r=0.581, p<0.01). CONCLUSION: IIM cases have altered LA reservoir and conduit functions, and LA strain could reflect LA function.

Magnetic resonance imaging scoring system of the lower limbs in adult patients with suspected idiopathic inflammatory myopathy.

PURPOSE: We aim to propose a visual quantitative score for muscle edema in lower limb MRI to contribute to the diagnosis of idiopathic inflammatory myopathy (IIM). MATERIAL AND METHODS: We retrospectively evaluated 85 consecutive patients (mean age 57.4 ± 13.9 years; 56.5% female) with suspected IIM (muscle weakness and/or persistent hyper-CPK-emia with/without myalgia) who underwent MRI of lower limbs using T2-weighted fast recovery-fast spin echo images and fat-sat T2 echo planar images. Muscle inflammation was evaluated bilaterally in 11 muscles of the thigh and eight muscles of the leg. Edema in each muscle was graded according to a four-point Likert-type scale adding up to 114 points ([11 + 8)] × 3 × 2). Diagnostic accuracy of the total edema score was explored by assessing sensitivity and specificity using the area under the ROC curve. Final diagnoses were made by a multidisciplinary Expert Consensus Panel applying the Bohan and Peter diagnostic criteria whenever possible. RESULTS: Of the 85 included patients, 34 (40%) received a final diagnosis of IIM (IIM group) while 51 (60%) received an alternative diagnosis (non-IIM group). A cutoff score ≥ 18 was able to correctly classify patients having an IIM with an area under the curve of 0.85, specificity of 96%, and sensitivity of 52.9%. CONCLUSION: Our study demonstrates that a quantitative MRI score for muscle edema in the lower limbs (thighs and legs) aids in distinguishing IIM from conditions that mimic it.

A protocol for scoping reviews on the role of whole-body and dedicated body-part magnetic resonance imaging for assessment of adult and juvenile idiopathic inflammatory myopathies.

Currently, standardized magnetic resonance imaging (MRI) scoring systems and protocols for assessment of idiopathic inflammatory myopathies (IIMs) in children and adults are lacking. Therefore, we will perform a scoping review of the literature to collate and evaluate the existing semi-quantitative and quantitative MRI scoring systems and protocols for the assessment and monitoring of skeletal muscle involvement in patients with IIMs. The aim is to compile evidence-based information that will facilitate the future development of a universal standardized MRI scoring system for both research and clinical applications in IIM. A systematic search of electronic databases (PubMed, EMBASE, and Cochrane) will be undertaken to identify relevant articles published between January 2000 and October 2023. Data will be synthesized narratively. This scoping review seeks to comprehensively summarize and evaluate the evidence on the scanning protocols and scoring systems used in the assessment of diagnosis, disease activity, and damage using skeletal muscle MRI in IIMs. The results will allow the development of consensus recommendations for clinical practice and enable the standardization of research methods for the MRI assessment of skeletal muscle changes in patients with IIMs.

Pathological findings with vacuoles in anti-mitochondrial antibody-positive inflammatory myopathy.

BACKGROUND: A few patients with inflammatory myopathy showed anti-mitochondrial antibody (AMA) positivity. This study aimed to report the clinical and pathological findings with vacuoles in 3 cases of such patients. METHODS: Three cases with myositis from the Myositis Clinical Database of Peking University First Hospital were identified with AMA positivity. Their clinical records were retrospectively reviewed and the data was extracted. All the 3 cases underwent muscle biopsy. RESULTS: Three middle-aged patients presented with chronic-onset weakness of proximal limbs, marked elevation of creatine kinase, and AMA-positivity. Two of the 3 cases meet the criteria of primary biliary cholangitis. All the 3 cases presented with cardiac involvement and proteinuria. Two cases developed type 2 respiratory failure. MRI of the thigh muscle showed multiple patches of edema bilaterally in both cases, mostly in the adductor magnus. Pathological findings include degeneration of muscle fibers, diffused MHC-I positivity, and complement deposits on cell membranes. Vacuoles without rims of different sizes were discovered under the membrane of the muscle fibers. A few RBFs were discovered in case 1, while a diffused proliferation of endomysium and perimysium was shown in case 2. CONCLUSIONS: AMA-positive inflammatory myopathy is a disease that could affect multiple systems. Apart from inflammatory changes, the pathological findings of muscle can also present vacuoles.

Post-streptococcal myositis - ultrasound features of an under-recognised disorder: a case report.

BACKGROUND: Post-streptococcal myalgia and myositis are very rare complications of streptococcal infections with group A ß-haemolytic streptococci. Data on this condition are scarce and even less is known about findings in clinical imaging. Until today, there are no descriptions of ultrasonographic changes in this condition. CASE PRESENTATION: We present a case of a 31-year-old female patient with immobilizing myalgia of the left outer thigh following a streptococcal upper respiratory tract infection, accompanied with erythemata nodosa on both shins. Laboratory results indicated post-streptococcal myositis since Creatine kinase, Lactate dehydrogenase and Antistreptolysin antibodies were significantly elevated. An ultrasound of the affected vastus medialis of the left quadriceps femoris muscle was performed, which showed a focal increase in muscle echogenicity with loss of architecture and hypervascularisation in Power Doppler Mode. The diagnosis of focal myositis was confirmed with magnetic resonance imaging. The patient's symptoms as well as the ultrasonographic changes fully resolved under therapy with Ibuprofen and intravenous Ampicillin/Sulbactam. CONCLUSIONS: This is the first description of ultrasound findings in this rare condition. We conclude that muscular ultrasound is helpful to identify myositis in post-streptococcal myalgia and myositis.

Non-negligible ultrasonographic findings in sarcoid myositis: A case series and literature review.

Sarcoid myositis is a rare and often debilitating extrapulmonary manifestation of sarcoidosis that can be difficult to recognize without a prior sarcoidosis diagnosis. Sarcoidosis with muscle nodules or masses as the first symptom is the least common form, occurring in approximately 0.5%-2.3% of cases. This article presents four middle-aged female patients who initially sought medical attention for a lower limb mass. Ultrasound examinations revealed consistent characteristic changes indicative of myositis. All patients underwent ultrasound-guided muscle biopsy and were diagnosed with sarcoidosis. Therefore, ultrasonography plays a pivotal role as the primary diagnostic tool for the early detection of sarcoid myositis.

[Establishing a predictive model for the activity of idiopathic inflammatory myopathy based on MRI and clinical features].

Objective: To analyze MRI and clinical characteristics of idiopathic inflammatory myopathy (IIM) activity and construct a prediction model. Methods: A retrospective analysis was conducted on 326 patients with IIM from December 2019 to December 2023 at General Hospital of Ningxia Medical University, including 112 males and 214 females, aged(53.7±15.3) years. According to histopathology and electromyography, they were divided into active phase group(n=86) and inactive phase group (n=240). The two groups were randomly divided into the training set and the verification set according to the ratio of 7∶3. The single factor analysis, least absolute shrinkage and selection operator (Lasso), random forest algorithm, and multivariate logistic regression model were used to screen the risk factors of IIM activity and construct a prediction model. Receiver operating characteristic (ROC) curve and calibration curve were used to evaluate the performance of prediction model. Results: There were significant differences in gender, age, T1 value, T2 value, creatine kinase-MB(CKMB), creatine kinase (CK) and lactate dehydrogenase (LDH) between the two groups(all P<0.05). Lasso and random forest algorithm screened 5 variables for analysis, age (λ=-0.009), T2 value (λ=-2.564), CKMB (λ=-0.256), CK (λ=-0.492), LDH (λ=-2.786) respectively. Multivariate logistic regression model showed that age (OR=1.603, 95%CI: 1.030-1.096), T2(OR=352.269, 95%CI: 13.303-9 328.053), CKMB (OR=2.470, 95%CI: 1.497-4.075), CK(OR=4.973, 95%CI: 2.583-9.575), LDH(OR=1 155.247, 95%CI: 152.387-8 757.954) were risk factors for active IIM patients. A prediction model nomograms were drawn with the above risk factors included. The area under the ROC curve (AUC) of the prediction model for the training set MRI combined with clinical indicators was higher than that of the clinical indicator model [0.914 (95%CI: 0.873-0.955) vs 0.901 (95%CI: 0.858-0.945), P<0.001], with sensitivity of 88.3% and 90.7%, and specificity of 81.7% and 75.0%, respectively. The AUC of the prediction model for the validation set MRI combined with clinical indicators was higher than that of the clinical model [0.982 (95%CI: 0.873-0.955) vs 0.934 (95%CI: 0.858-0.945), P<0.001], with sensitivity of 97.2% and 88.5%, and specificity of 100.0% and 92.3%, respectively. The calibration curves plotted in the training set and test set, respectively, fit well with the ideal curve. Conclusion: The nomogram model of MRI combined with clinical indicators can effectively predict the activity of IIM.

Assessing PET/CT's diagnostic accuracy in idiopathic myopathies.

OBJECTIVE: Recent studies have utilized fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) specifically to diagnose cases of idiopathic inflammatory myopathies (IIM), excluding inclusion body myositis (IBM). Conversely, carbon-11 (11C) labeled Pittsburgh compound B (PIB)-PET imaging is exclusively used for the detection of IBM. This research is designed to evaluate the diagnostic accuracy of PET/CT in identifying IIM by employing rigorous diagnostic accuracy testing methodologies. MATERIALS AND METHODS: A systematic review and meta-analysis were conducted across multiple databases including PubMed, and Embase. We focused on the diagnostic utility of PET/CT in IIM, assessing sensitivities, specificities, and deriving likelihood ratios (LR+ and LR-). The study was registered with PROSPERO (CRD42022343222). RESULTS: This systematic review identified 635 citations, of which 10 eligible trials were included, with a total of 419 participants. The results indicated a sensitivity of 0.86 (0.81-0.90), and a specificity of 0.93 (0.88-0.96). The synthesis of LR revealed the LR+ of 10.35 (6.31-16.98), and LR-of 0.15 (0.07-0.32). The summary receiver operating characteristic curve (SROC) showed an area under the curve (AUC) of 0.9658. Regarding IBM, the sensitivity was 0.84 (0.60-0.97), and the specificity was 1 (0.69-1). The synthesis of LR showed the LR+ of 9.61 (1.46-63.15) and an LR- of 0.21 (0.09-0.51). For disease activity, the sensitivity was 0.96 (0.92-0.99), and the specificity was 0.91 (0.084-0.96). The synthesis of LR showed an LR+ of 9.43 (5.39-16.51) and an LR- of 0.05 (0.02-0.11). CONCLUSION: Positron emission tomography/CT has great potential for accurately diagnosing and monitoring patients with IIM, and may have implications for their clinical management.

[A lightweight convolutional neural network for myositis classification from muscle ultrasound images].

Existing classification methods for myositis ultrasound images have problems of poor classification performance or high computational cost. Motivated by this difficulty, a lightweight neural network based on a soft threshold attention mechanism is proposed to cater for a better IIMs classification. The proposed network was constructed by alternately using depthwise separable convolution (DSC) and conventional convolution (CConv). Moreover, a soft threshold attention mechanism was leveraged to enhance the extraction capabilities of key features. Compared with the current dual-branch feature fusion myositis classification network with the highest classification accuracy, the classification accuracy of the network proposed in this paper increased by 5.9%, reaching 96.1%, and its computational complexity was only 0.25% of the existing method. The obtained results support that the proposed method can provide physicians with more accurate classification results at a lower computational cost, thereby greatly assisting them in their clinical diagnosis.

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.

Accuracy of power Doppler ultrasonography in the diagnosis and monitoring of idiopathic inflammatory myopathies.

OBJECTIVES: No clear-cut guidelines exist for the use of imaging procedures for the diagnosis of idiopathic inflammatory myopathies (IIM). The aim of the present study was to assess the diagnostic accuracy of power Doppler ultrasonography (PDUS) score in IIM patients compared with a control group and its usefulness during follow-up. METHODS: All patients evaluated in the Vasculitis and Myositis Clinic, Rheumatology Unit, University of Siena were prospectively collected. All patients underwent US examination of both thighs in axial and longitudinal scans, which were also performed twice (T1) or three times (T2). RESULTS: Forty-five patients with IIM (median [interquartile range] age 55 [45-66] years; 35 female) were enrolled. Receiver operating characteristic curves distinguished patients and controls based on ∑power Doppler (PD), ∑oedema, ∑atrophy and CRP. The best cut-off value for ∑PD was 0.5, ∑oedema 1.5, ∑atrophy 0.5 and CRP 0.22 mg/dl. In a logistic regression analysis, the variables that most influenced diagnosis of IIM were ∑PD and ∑oedema (P = 0.017 and P = 0.013, respectively). ∑Oedema was lower at T1 (P = 0.0108) and T2 (P = 0.0012) than at T0. Likewise, ∑PD was lower at T1 (P = 0.0294) and T2 (P = 0.0420) than at T0. Physician global assessment was lower at T1 (P = 0.0349) and T2 (P = 0.0035) than at baseline. CONCLUSION: Our findings show that PDUS is a reliable diagnostic tool in the differential diagnosis between inflammatory and non-inflammatory myopathies. Moreover, PDUS can be employed also during the follow-up of patients with IIM. A reduction in disease activity, measured by physician global assessment, led to a concomitant decrease in both oedema and PD, which was directly correlated with their rate of change. This underlines the close link between clinical assessment and PDUS findings, not only at diagnosis but also during monitoring.

Quantitative interstitial lung disease scores in idiopathic inflammatory myopathies: longitudinal changes and clinical implications.

OBJECTIVES: To investigate computer-aided quantitative scores from high-resolution CT (HRCT) images and determine their longitudinal changes and clinical significance in patients with idiopathic inflammatory myopathies (IIMs)-related interstitial lung disease (IIMs-ILD). METHODS: The clinical data and HRCT images of 80 patients with IIMs who underwent serial HRCT scans at least twice were retrospectively analysed. Quantitative ILD (QILD) scores (%) were calculated as the sum of the extent of lung fibrosis, ground-glass opacity, and honeycombing. The individual time-estimated ΔQILD between two consecutive scans was derived using a linear approximation of yearly changes. RESULTS: The baseline median QILD (interquartile range) scores in the whole lung were 28.1% (19.1-43.8). The QILD was significantly correlated with forced vital capacity (r = -0.349, P = 0.002) and diffusing capacity for carbon monoxide (r = -0.381, P = 0.001). For ΔQILD between the first two scans, according to the visual ILD subtype, QILD aggravation was more frequent in patients with usual interstitial pneumonia (UIP) than non-UIP (80.0% vs 44.4%, P = 0.013). Multivariable logistic regression analyses identified UIP was significantly related to radiographic ILD progression (ΔQILD >2%, P = 0.015). Patients with higher baseline QILD scores (>28.1%) had a higher risk of lung transplantation or death (P = 0.015). In the analysis of three serial HRCT scans (n = 41), dynamic ΔQILD with four distinct patterns (improving, worsening, convex and concave) was observed. CONCLUSION: QILD changes in IIMs-ILD were dynamic, and baseline UIP patterns seemed to be related to a longitudinal progression in QILD. These may be potential imaging biomarkers for lung function, changes in ILD severity and prognosis in IIMs-ILD.

Correlation of muscle ultrasound with clinical and pathological findings in idiopathic inflammatory myopathies.

INTRODUCTION/AIMS: In idiopathic inflammatory myopathies (IIMs), the change in muscle echogenicity and its histopathological basis are not well understood. We quantitatively measured muscle echogenicity in patients with IIMs and evaluated its correlation with disease activity and histopathological findings. METHODS: This study involved patients with IIMs who underwent both ultrasonography (US) and muscle biopsy, as well as age- and sex-matched rheumatoid arthritis patients as inflammatory disease controls. On US, axial images of the right biceps brachii and vastus medialis were obtained. Standardized histopathological scoring was used to quantitatively measure each pathological domain. RESULTS: Forty-two patients (17 with inclusion body myositis [IBM] and 25 with IIMs other than IBM) and 25 controls were included. The muscle echo intensity (EI) of patients with IIMs was significantly higher than that of controls. Muscle EI showed significant correlations with creatine kinase (r = 0.66, p < .001) and muscle strength (r = -0.73, p < .0001) in patients with non-IBM IIMs. In patients with IBM, moderate correlation was found between muscle EI and quadriceps muscle strength (r = -0.53, p = .028). Histopathologically, the number of infiltrating CD3+ inflammatory cells correlated with muscle EI in the non-IBM group (r = 0.56, p = .017), but not in the IBM group. DISCUSSION: Muscle EI may be useful as a surrogate marker of muscle inflammation in non-IBM IIM. Increased muscle EI may be difficult to interpret in patients with long-standing IBM, which has advanced and complex histopathology.