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.

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.

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.

Correlation analysis of quantitative MRI measurements of thigh muscles with histopathology in patients with idiopathic inflammatory myopathy.

OBJECTIVES: To validate the correlation between histopathological findings and quantitative magnetic resonance imaging (qMRI) fat fraction (FF) and water T2 mapping in patients with idiopathic inflammatory myopathy (IIM). METHODS: The study included 13 patients with histopathologically confirmed IIM who underwent dedicated thigh qMRI scanning within 1 month before open muscle biopsy. For the biopsied muscles, FF derived from the iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) and T2 time from T2 mapping with chemical shift selective fat saturation were measured using a machine learning software. Individual histochemical and immunohistochemical slides were evaluated using a 5-point Likert score. Inter-reader agreement and the correlation between qMRI markers and histopathological scores were analyzed. RESULTS: Readers showed good to perfect agreement in qMRI measurements and most histopathological scores. FF of the biopsied muscles was positively correlated with the amount of fat in histopathological slides (p = 0.031). Prolonged T2 time was associated with the degree of variation in myofiber size, inflammatory cell infiltration, and amount of connective tissues (p ≤ 0.008 for all). CONCLUSIONS: Using the machine learning-based muscle segmentation method, a positive correlation was confirmed between qMRI biomarkers and histopathological findings of patients with IIM. This finding provides a basis for using qMRI as a non-invasive tool in the diagnostic workflow of IIM. RELEVANCE STATEMENT: By using ML-based muscle segmentation, a correlation between qMRI biomarkers and histopathology was found in patients with IIM: qMRI is a potential non-invasive tool in this clinical setting. KEY POINTS: • Quantitative magnetic resonance imaging measurements using machine learning-based muscle segmentation have good consistency and reproductivity. • Fat fraction of idiopathic inflammatory myopathy (IIM) correlated with the amount of fat at histopathology. • Prolonged T2 time was associated with muscle inflammation in IIM.

[A case of atezolizumab- and bevacizumab-induced myositis showing high intensity in the pterygoid muscles, soft palate, and tongue on STIR-MRI].

A 61-year-old woman was treated with atezolizumab plus bevacizumab for hepatocellular carcinoma with peritoneal dissemination. Blood tests revealed elevated creatine kinase (CK) that peaked at 2,657 U/l. After two cycles of atezolizumab plus bevacizumab combination therapy, she complained of progressive dysarthria and dysphagia. Needle electromyography showed myopathic changes. Initial MRI showed high signal intensity in the orbicularis oris muscle, soft palate, tongue, pterygoid muscles, and paravertebral muscles on STIR images. Myositis-specific autoantibodies were not detected. Based on these findings, the patient was diagnosed with immune checkpoint inhibitor-associated myositis. The clinical symptoms improved after administration of oral prednisone, and follow-up MRI showed reduced extent of areas of high signal intensity and almost complete resolution of signal abnormality in the paravertebral muscles. The CK level normalized after 1 months of oral steroid administration. MRI of the head and neck, including the tongue and soft palate, may be useful in diagnosis and for evaluating therapeutic efficiency in cases of bulbar symptoms that occur following the introduction of immune checkpoint inhibitors.

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.

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.

Diagnostic Yield of Computed Tomography for Cancer Detection in a Tertiary Referral Population of Idiopathic Inflammatory Myositis Patients.

OBJECTIVE: To inform guidance for cancer detection in patients with idiopathic inflammatory myopathy (IIM), we evaluated the diagnostic yield of computed tomography (CT) imaging for cancer screening/surveillance within distinct IIM subtypes and myositis-specific autoantibody strata. METHODS: We conducted a single-center, retrospective cohort study in IIM patients. Overall diagnostic yield (number of cancers diagnosed/number of tests performed), percentage of false positives (number of biopsies performed not leading to cancer diagnosis/number of tests performed), and test characteristics were determined on CT of the chest and abdomen/pelvis. RESULTS: Within the first 3 years since IIM symptom onset, a total of 9 of 1,011 (0.9%) chest CT scans and 12 of 657 (1.8%) abdomen/pelvis CT scans detected cancer. Diagnostic yields for both CT of the chest and CT of the abdomen/pelvis were highest in dermatomyositis, specifically anti-transcription intermediary factor 1γ (2.9% and 2.4% for CT of the chest and abdomen/pelvis, respectively). The highest percentage of false positives was in patients with antisynthetase syndrome (ASyS) (4.4%) and immune-mediated necrotizing myopathy (4.4%) on CT of the chest, and ASyS (3.8%) on CT of the abdomen/pelvis. Patients ages <40 years old at IIM onset had both low diagnostic yields (0% and 0.5%) and high false-positive rates (1.9% and 4.4%) for CT of the chest and abdomen/pelvis, respectively. CONCLUSION: In a tertiary referral cohort of IIM patients, CT imaging has a wide range of diagnostic yield and frequency of false positives for contemporaneous cancer. These findings suggest that cancer detection strategies targeted according to IIM subtype, autoantibody positivity, and age may maximize cancer detection while minimizing the harms and costs of over-screening.

Sarcopenia and Myositis Revisited: Emerging Role of Fluorine-18 Fluorodeoxyglucose PET in Muscle Imaging.

Fluorodeoxyglucose (FDG) PET/computed tomography (CT) is a valuable diagnostic modality in the work-up of patients with suspected inflammatory myopathy. Sarcopenia and metabolic muscle activity on staging FDG PET/CT has been shown to correlate with overall survival in certain oncologic settings. Knowledge of the physiologic FDG uptake in skeletal muscles and optimization of imaging protocols are key for proper image analysis.

Caracterización clínico-radiológica de pacientes con enfermedad pulmonar intersticial y panel de miositis positivo en hospital Santiago Oriente / Clinical-radiological characterization of patients with interstitial lung disease and positive myositis panel at hospital Santiago Oriente

Introducción: Las Enfermedades Pulmonares Intersticiales (EPI) afectan principalmente al intersticio pulmonar, con importante morbimortalidad asociada. Tienen un espectro de posibles etiologías que es cada vez más amplio. Hay una importante causalidad a partir de Enfermedades del Tejido Conectivo (ETC), describiéndose cada vez más casos asociados a Síndrome Antisintetasa, y con diversos patrones radiológicos según serología obtenida, agrupada en "Panel de Miositis" (PaM). El presente estudio de cohorte retrospectiva reúne PaMs realizados en el Hospital Santiago Oriente, correlacionando resultados con manifestaciones clínicas e imagenológicas. Material y Métodos: Se recuperaron 33 PaMs realizados entre 2017 y 2022, y a través de revisión de fichas de los pacientes de quienes provenían las PaMs se consignaron las principales manifestaciones clínicas, imagenológicas y de la serología reumatológica complementaria, estableciendo correlaciones entre múltiples variables. Resultados: Hubo 15 pacientes PaM positivos (45,4%), 8 de ellos (53%) ya contaban con alguna miopatía inflamatoria diagnosticada. Los principales hallazgos clínicos consignados fueron pápulas de Gottron, artritis, eritema heliotropo, Fenómeno de Raynaud y fiebre. El anticuerpo positivo más frecuente fue Ro-52. Se pudo objetivar ANA positivo en 10 casos (66,7%). Se identificó EPI en 66,7% de aquellos con PaM positivo, siendo la Neumonía Intersticial no específica fibrótica con Neumonía en Organización la manifestación más frecuente. No hubo asociación significativa entre manifestaciones imagenológicas y anticuerpos específicos. Se encontró ANA 1/80 en 66,7% de los casos, lo cual no se asoció a mayor riesgo de EPI. Conclusiones: Existe asociación entre varias ETC y las EPI. Destaca la importancia de los hallazgos clínicos para establecer un adecuado índice de sospecha, para dirigir oportunamente el estudio complementario (ej: PaM), y la eventual terapia específica.

Introduction: Interstitial Lung Diseases (ILD) mainly affect the pulmonary interstitium, with significant associated morbidity and mortality. They have a spectrum of possible etiologies that is increasingly broad. There is an important causality from Connective Tissue Diseases (CTD), describing more and more cases associated with Antisynthetase Syndrome, and with different radiological patterns according to the serology obtained, enclosed into "Panel of Myositis" (PaM). This retrospective cohort study gathers PaMs performed at Hospital Santiago Oriente, PaM results are correlated with clinical and imaging manifestations. Material and Methods: 33 PaMs performed between 2017 and 2022 were saved up and by reviewing the clinical records of the patients from whom the PaMs came, their clinical and radiological manifestations and the results of their complementary rheumatological serology were recorded to establish correlations between multiple variables. Results: There were 15 positive PaMs (45.4%), 8 (53%) of them already had some diagnosed inflammatory myopathy. The main clinical findings reported were Gottron's papules, arthritis, heliotrope erythema, Raynaud's phenomenon, and fever. The most frequent positive antibody detected was Ro-52. Positive ANA could be found in 10 cases (66.7%). PID was identified in 66.7% of those with a positive PaM, being non-specific fibrotic Interstitial Pneumonia with Organizing Pneumonia being the most frequent manifestation. There was no significant association between imaging manifestations and specific antibodies. ANA 1/80 was found in 6.7% of the cases, which was not associated with an increased risk of PID. Conclusions: There is association between several CTEs and EPIs. It is necessary to highlight the importance of the clinical findings to establish an adequate index of suspicion, in order to timely direct the complementary study (eg: PaM), and the eventual specific therapy.

Defining the clinical utility of PET or PET-CT in idiopathic inflammatory myopathies: A systematic literature review.

OBJECTIVES: Positron emission tomography (PET), often combined with computed tomography (CT), is a well-established tool for diagnosing malignancy and inflammatory disease. The idiopathic inflammatory myopathies (IIM) are chronic, multi-system diseases characterised by skeletal muscle inflammation, the potential for extramuscular manifestations such as interstitial lung disease (ILD) and an increased risk of malignancy. We performed a systematic literature review to evaluate the utility of PET or PET-CT in evaluation of IIM. METHODS: A search of Medline and EMBASE from 1990 to 2022 using keywords related to IIM and PET was performed. English language studies of adults with IIM who had PET or PET-CT were included. RESULTS: Our search identified 1173 potentially relevant abstracts, 19 of which were included. The majority of studies used [18F] fluorodeoxyglucose (FDG) PET or PET-CT scans, while the remainder used [18F] florbetapir and [11C] Pittsburgh compound B ([11C] PIB). The sensitivity and specificity of 18F-FDG-PET or 18F-FDG-PET-CT for diagnosing malignancy compared with standard detection methods was 66.7-94% and 80-97.8%, respectively. The sensitivity of 18F-FDG PET-CT for ILD was 93-100% when high-resolution CT was used as the reference standard. 18F-PET and 18F-FDG-PET-CT appear to accurately detect muscle inflammation, although correlations with clinical measures of IIM disease activity were variable. [18F] florbetapir PET-CT and [11C] PIB PET were able to differentiate sporadic inclusion body myositis (IBM) from non-IBM IIM. CONCLUSION: PET-CT holds promise as a single tool that can simultaneously evaluate multiple aspects of IIM. These include screening for associated malignancy, achieving an early diagnosis of ILD and evaluating muscle inflammation.

Covid-19 associated shoulder girdle calcific myositis: a novel entity.

OBJECTIVE: To investigate the prevalence, describe the radiological features, and consider the clinical sequelae of COVID-19- associated shoulder girdle calcific myositis. METHODS: All patients who underwent a CT pulmonary angiogram study at our institution (Queen Alexandra Hospital, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom) in April and May 2020, January 2021, and July 2021 were included. A total of 1239 CT pulmonary angiogram studies for 1201 patients were reviewed. Patients with COVID-19 and associated shoulder girdle calcific myositis were identified. Their electronic patient records were reviewed. The patients' demographics, serum inflammatory markers, and proning history were recorded. RESULTS: Of the 364 patients in Wave 1, 71 patients (19.5%) had COVID-19, and of those, 2 patients (2.8%) had shoulder girdle calcific myositis. Of the 521 patients in Wave 2, 354 patients (67.9%) had COVID-19, and of those, 3 patients (0.8%) had shoulder girdle calcific myositis. Of the 316 patients in Wave 3, 37 patients (11.7%) had COVID-19, and of those, 1 patient (2.7%) had shoulder girdle calcific myositis. The overall prevalence was 1.3%. The most common site of calcific myositis was within the subscapularis muscle. CONCLUSION: COVID-19-associated shoulder girdle calcific myositis is a rare extrapulmonary musculoskeletal manifestation of COVID-19. Early recognition and increased awareness of this disease entity, in our experience, aids in reducing patient morbidity and improving long-term functional outcome. ADVANCES IN KNOWLEDGE: We have reported a novel disease entity associated with COVID-19, in the form of shoulder girdle calcific myositis. We have described the common imaging features and discussed our experience of management and clinical sequelae.

18F-FDG PET/CT and HRCT: a combined tool for risk stratification in idiopathic inflammatory myopathy-associated interstitial lung disease.

OBJECTIVES: Rapidly progressive interstitial lung disease (RP-ILD) is a life-threatening form of idiopathic inflammatory myopathy (IIM)-associated interstitial lung disease (ILD). We aimed to assess the combination of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) and high-resolution computed tomography (HRCT) for the quantification of IIM-ILD activity and risk stratification for RP-ILD. METHOD: Patients with IIM and undergoing 18F-FDG PET/CT were included in this retrospective study. Pulmonary FDG uptake was assessed using the maximum standardized uptake value (SUVlung) and visual score (PET score). HRCT was evaluated using visual analysis (HRCT score). Multivariable logistic regression was used to identify risk factors for RP-ILD. RESULTS: Seventy-three patients with IIM (17 with RP-ILD, 38 with non-RP-ILD, and 18 without ILD) were included. SUVlung, PET score, and HRCT score were significantly higher in RP-ILD than in non-RP-ILD. Strong positive correlations were observed between SUVlung, PET score, and the HRCT parameters. The area under the curve (AUC) of the PET score to differentiate between RP-ILD and non-RP-ILD (AUC = 0.860) was higher than that of the SUVlung (AUC = 0.802) and HRCT scores (AUC = 0.806). We developed a risk score based on the number of positive risk factors (PET score > 18, HRCT score > 140, and positive anti-melanoma differentiation-associated gene 5 (MDA5) antibody) to differentiate between RP-ILD and non-RP-ILD (AUC = 0.955). Patients with higher risk scores had significantly worse prognoses. CONCLUSIONS: 18F-FDG PET/CT is useful for assessing disease activity in patients with IIM-ILD. The combination of PET score, HRCT score, and anti-MDA5 antibody can be used to identify patients at increased risk of RP-ILD and with poor prognoses.

Cancer and immune-mediated necrotizing myopathy: a longitudinal referral case-controlled outcomes evaluation.

OBJECTIVES: To investigate immune-mediated necrotizing myopathy (IMNM) association with cancer and its clinical implications. METHODS: IMNM cases were identified 1 January 2000 to 31 December 2020 matching sex and age controls (4:1). RESULTS: A total of 152 patients with IMNM were identified and among serologically tested, 60% (83/140) were HMGCR-IgG+, 14% (20/140) were SRP-IgG+ and 26% (37/140) were seronegative. Cancer rates were not significantly different between serological subgroups; 18.1% (15/83) HMGCR-IgG+, 25% (5/20) SRP-IgG+ and 30% (11/37) seronegative (P = 0.34). Cancer screening was performed within 12 months from IMNM diagnosis in 88% (134/152) (whole-body CT plus FDG-PET CT in 53, CT alone in 72 and FDG-PET alone in 9). FDG-PET/CT was positive in 73% (25/34) of cancers. Increasing age was the only risk associated with cancer (P = 0.02). The odds of developing cancer at ±3 or ±5 years from IMNM diagnosis was not higher than controls (OR = 0.49; CI: 0.325-0.76). Lifetime IMNM diagnosis of cancer was less compared with controls (OR = 0.5 CI: 0.33-0.78, P = 0.002). Most patients responded to treatment (137/147, P < 0.001). Death and treatment response did not significantly differ between cancer [23% (8/34); 88% (29/33)] and non-cancer patients [19% (23/118); 92% (108/118)]. In total, 13% (20/152) of patients died during follow-up compared with 14% (41/290) of medicine and 16% (46/290) of neurology controls (P = 0.8). Seropositives had greater life expectancy than seronegatives (P = 0.01). CONCLUSIONS: Greater cancer risk is not observed in IMNM vs controls. Cancer screening in IMNM should be individualized based on age-personal and family history, including consideration of FDG-PET/CT. Immune-treatment response did not differ with cancer.