High-frequency ultrasound of the skin in systemic sclerosis: an exploratory study to examine correlation with disease activity and to define the minimally detectable difference

Skin Ultrasound Assessment of Patients with Systemic Scleroderma-An Observational Study

This study aims to analyze the changes in dermal thickness in patients with systemic scleroderma (SSc) in comparison with normal skin and also compare clinical forms with diffuse and limited cutaneous involvement. The study group consisted of female patients diagnosed with SSc with a disease history not exceeding 5 years. The areas of interest for ultrasound examination included the proximal phalanx of the third finger, the second intermetacarpal space, and the extension surface of the lower third of the forearm. The study included 20 patients diagnosed with SSc and 14 controls. SSc patients were subdivided into two subgroups based on the clinical form. Compared to the control group, patients with SSc had higher mean measurements in all three skin areas, with statistically significant differences in the hand and forearm areas. Patients with diffuse SSc displayed, on average, higher skin thickness compared to limited SSc in all skin areas examined, with a statistically significant difference only in the forearm area. Based on disease manifestations, significant differences were observed only with regard to the presence of pulmonary hypertension in the diffuse SSc group. In conclusion, skin ultrasound is a useful and accessible imaging method for diagnosing and quantifying dermal fibrosis in systemic scleroderma.

Ultrasound measurement of traumatic scar and skin thickness: a scoping review of evidence across the translational pipeline of research-to-practice

OBJECTIVES

To identify the ultrasound methods used in the literature to measure traumatic scar thickness, and map gaps in the translation of these methods using evidence across the research-to-practice pipeline.

DESIGN

Scoping review.

DATA SOURCES

Electronic database searches of Ovid MEDLINE, Embase, Cumulative Index of Nursing and Allied Health Literature and Web of Science. Grey literature searches were conducted in Google. Searches were conducted from inception (date last searched 27 May 2022).

DATA EXTRACTION

Records using brightness mode (B-mode) ultrasound to measure scar and skin thickness across the research-to-practice pipeline of evidence were included. Data were extracted from included records pertaining to: methods used; reliability and measurement error; clinical, health service, implementation and feasibility outcomes; factors influencing measurement methods; strengths and limitations; and use of measurement guidelines and/or frameworks.

RESULTS

Of the 9309 records identified, 118 were analysed (n=82 articles, n=36 abstracts) encompassing 5213 participants. Reporting of methods used was poor. B-mode, including high-frequency (ie, >20 MHz) ultrasound was the most common type of ultrasound used (n=72 records; 61% of records), and measurement of the combined epidermal and dermal thickness (n=28; 24%) was more commonly measured than the epidermis or dermis alone (n=7, 6%). Reliability of ultrasound measurement was poorly reported (n=14; 12%). The scar characteristics most commonly reported to be measured were epidermal oedema, dermal fibrosis and hair follicle density. Most records analysed (n=115; 97%) pertained to the early stages of the research-to-practice pipeline, as part of research initiatives.

CONCLUSIONS

The lack of evaluation of measurement initiatives in routine clinical practice was identified as an evidence gap. Diverse methods used in the literature identified the need for greater standardisation of ultrasound thickness measurements. Findings have been used to develop nine methodological considerations for practitioners to guide methods and reporting.

Multiparametric Skin Assessment in a Monocentric Cohort of Systemic Sclerosis Patients: Is There a Role for Ultra-High Frequency Ultrasound?

Background: To assess skin involvement in a cohort of patients with systemic sclerosis (SSc) by comparing results obtained from modified Rodnan skin score (mRSS), durometry and ultra-high frequency ultrasound (UHFUS). Methods: SSc patients were enrolled along with healthy controls (HC), assessing disease-specific characteristics. Five regions of interest were investigated in the non-dominant upper limb. Each patient underwent a rheumatological evaluation of the mRSS, dermatological measurement with a durometer, and radiological UHFUS assessment with a 70 MHz probe calculating the mean grayscale value (MGV). Results: Forty-seven SSc patients (87.2% female, mean age 56.4 years) and 15 HC comparable for age and sex were enrolled. Durometry showed a positive correlation with mRSS in most regions of interest (p = 0.025, ρ = 0.34 in mean). When performing UHFUS, SSc patients had a significantly thicker epidermal layer (p < 0.001) and lower epidermal MGV (p = 0.01) than HC in almost all the different regions of interest. Lower values of dermal MGV were found at the distal and intermediate phalanx (p < 0.01). No relationships were found between UHFUS results either with mRSS or durometry. Conclusions: UHFUS is an emergent tool for skin assessment in SSc, showing significant alterations concerning skin thickness and echogenicity when compared with HC. The lack of correlations between UHFUS and both mRSS and durometry suggests that these are not equivalent techniques but may represent complementary methods for a full non-invasive skin evaluation in SSc.

Use of new microcirculation software allows the demonstration of dermis vascularization

AIMS

Current ultrasound (US) Doppler techniques cannot demonstrate the vascularization of the dermis. The purpose of this study was to investigate whether the new Superb Vascular Imaging (SMI) and Microvascular Flow (MV-Flow) techniques improve the detection of normal dermis vessels. SMI and MV-Flow were compared side-by-side to conventional power-Doppler (PD) imaging.

METHODS

By using US, 50 healthy volunteers were evaluated at level of five body areas: forehead, forearm, palm, buttock, and thigh. Two off-site operators evaluated the images to assess the difference between SMI and PD imaging and between MV-Flow and PD imaging in terms of dermis flow amount. A 0-3 scoring system was adopted.

RESULTS

SMI scored grade 0 in 0% of body areas, grade 1 in 58%, grade 2 in 33%, and grade 3 in 9%. In comparison with SMI, PD scored grade 0 in 38% of body areas, grade 1 in 56%, grade 2 in 6%, and grade 3 in 0%. MV-Flow scored grade 0 in 0% of body areas, grade 1 in 52%, grade 2 in 43%, and grade 3 in 6%. Comparted to MV-Flow, PD scored grade 0 in 53% of body areas, grade 1 in 34%, grade 2 in 13%, and grade 3 in 0%. The difference in terms of sensitivity was statistically significant for all the body areas investigated.

CONCLUSIONS

We found both SMI and MV-Flow to be superior to PD imaging and capable to demonstrate normal vascularization of the dermis.

Novel therapies and innovation for systemic sclerosis skin ulceration

Skin ulceration is an important cause of morbidity in systemic sclerosis and can occur at anytime during disease progression. Incident disease cohorts are important for understanding whether skin ulceration represents active vasculopathy versus resultant damage. Biomarkers for skin ulcer pathogenesis, both serum and imaging, are under investigation to elucidate the functional consequences of the structural abnormalities. Novel therapeutics for the treatment of vasculopathy benefit from reliable biomarkers able to predict the disease evolution remains an important unmet need. Nonetheless, a diagnostic approach that captures early skin ulceration and treatments that restore vascular and immune homeostasis is critical for effective systemic sclerosis (SSc) vasculopathy management.

Role of shear wave elastography ultrasound in patients with systemic sclerosis

PURPOSE

A study of shear wave elastography (SWE) for evaluation of skin stiffness in systemic sclerosis (SSc) patients. The purpose of this study was to measure the skin stiffness and thickness in patients with scleroderma using shear wave elastography.

METHODS

Prospective data collections of skin stiffness and thickness using SWE in SSc and control groups.

RESULTS

Skin stiffness and thickness were done in 29 patients with SSc and a 29 control population using SWE on bilateral forearms. The SSc patients had thicker skin and higher stiffnesses than the control group. The mean of skin thickness and stiffness using SWE of SSc are 1.74 mm and 47.32 kPa while normal subjects were 1.5 mm and 19.5 kPa. Mean differences were 0.023 mm (95% CI 0.15-0.3, p < 0.001) and 27.82 kPa (95% CI 22.63-33.01, p < 0.001). The dorsal forearms tend to have a higher SWE than the volar forearms in SSc. No statistically significant differences between gender, age or dominancy of skin stiffness were found. SWE has a good correlation with clinical manual palpation of forearms (mRSS) with Spearman rho's of 0.550 (p = 0.002) and 0.508 (p = 0.005) of dominant and non-dominant forearms.

CONCLUSION

The application of SWE can be used for evaluation of skin involvement in scleroderma patients with good correlations with the mRSS that was used in the current patients. Furthermore, SWE is a safe technique for either diagnosis or follow up.

Updated Role of High-frequency Ultrasound in Assessing Dermatological Manifestations in Autoimmune Skin Diseases

Autoimmune skin diseases are a group of disorders that arise due to the dysregulated immune system attacking self-antigens, causing multiple tissue and organ lesions. With disease progression, the physical and psychological health of patients may be seriously damaged. High-frequency ultrasound is non-invasive, reproducible, and suitable for visualizing the fine structure of external organs. The usage of high-frequency ultrasound has increased in recent years in the auxiliary diagnosis and monitoring of various skin diseases; it serves as a promising tool for dermatological disease assessment. This review summarizes the characteristics of high-frequency ultrasound imaging in common autoimmune skin diseases, including systemic lupus erythematosus, scleroderma, psoriasis, dermatomyositis, and pemphigus/pemphigoid. The objective of this review is to provide new ideas and strategies for dermatologists to diagnose and track the prognosis of autoimmune skin diseases.

Clinical application of ultra-high frequency ultrasound: Discovering a new imaging frontier

The ultra-high frequency ultrasound (UHFUS) is characterized by the use of probes between 30 and 100 MHz. This technology has recently been introduced in clinical practice and represents an opportunity for the diagnosis of numerous pathologies. The high spatial resolution of UHFUS, up to 30 μ in pixel size, allows to study the pathological modifications and to guide microsurgery treatments in anatomical body structures not evaluable by conventional HFUS. The aim of this work is to provide a review of the literature on the current clinical applications of UHFUS and to discuss its added role in different clinical settings.

Ultrasound and elastography in the assessment of skin involvement in systemic sclerosis: A systematic literature review focusing on validation and standardization - WSF Skin Ultrasound Group

OBJECTIVE

To summarize the published evidence in the literature on the role of ultrasound and elastography to assess skin involvement in systemic sclerosis (SSc).

METHODS

A systematic literature review (SLR) was performed within the "Skin Ultrasound Working Group" of the World Scleroderma Foundation, according to the Cochrane Handbook. A search was conducted in Pubmed, Cochrane Library and Embase databases from 1/1/1979 to 31/5/2021, using the participants, intervention, comparator and outcomes (PICO) framework. Only full-text articles involving adults, reported in any language, assessing ultrasound to quantify skin pathology in SSc patients. Two reviewers performed the assessment of risk of bias, data extraction and synthesis, independently.

RESULTS

Forty-six studies out of 3248 references evaluating skin ultrasound and elastography domains were included. B-mode ultrasound was used in 30 studies (65.2%), elastography in nine (19.6%), and both methods in seven (15.2%). The ultrasound outcome measure domains reported were thickness (57.8%) and echogenicity (17.2%); the elastography domain was stiffness (25%). Methods used for image acquisition and analysis were remarkably heterogeneous and frequently under-reported, precluding data synthesis across studies. The same applies to contextual factors and feasibility. Our data syntheses indicated evidence of good reliability and convergent validity for ultrasound thickness evaluation against mRSS and skin histological findings. Stiffness and echogenicity have limited evidence for validity against histological findings. Evidence for sensitivity to change, test-retest reliability, clinical trial discrimination or thresholds of meaning is limited or absent for reported ultrasound domains.

CONCLUSION

Ultrasound is a valid and reliable tool for skin thickness measurement in SSc but there are significant knowledge gaps regarding skin echogenicity assessment by ultrasound and skin stiffness evaluation by elastography in terms of feasibility, validity and discrimination. Standardization of image acquisition and analysis is needed to foster progress.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

Ultrasound measurements of pathological and physiological skin thickness: a scoping review protocol

INTRODUCTION

Ultrasound is a quick, safe, and non-invasive imaging method that can be used to measure skin thickness in pathological cutaneous conditions in clinical and research settings. Despite widespread use, there exists a lack of standardisation and reporting of ultrasound skin thickness measurement methods, which makes between-studies comparisons difficult. To address this, we present a scoping review protocol, which aims to determine what is and is not known about the measurement of skin and scar thickness using ultrasound in people with traumatic scars.

METHODS AND ANALYSIS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines and Joanna Briggs Institute scoping review methodology will be used to guide this review. Electronic database searching will be conducted in Ovid MEDLINE, Embase, Cumulative Index of Nursing and Allied Health Literature and Web of Science. No date limit will be imposed on the database searches. Records will be supplemented with searches of reference lists of included studies and grey literature in OpenGrey and Google Advanced. Screening will be conducted by two independent reviewers, and studies where ultrasound is used to measure skin and scar thickness in people with traumatic scars will be included. Data extraction will include ultrasound methods (eg, transducer orientation), psychometric properties (eg, reliability, measurement error), health service and implementation outcomes (eg, feasibility, acceptability) and factors influencing ultrasound measurement of skin thickness (eg, body location, age).

ETHICS AND DISSEMINATION

Ethical approval is not required for this investigation, as published literature will form the basis of the review. The review will be published in a peer-reviewed scientific journal and is expected to result in the development of the first evidence-based and consensus-based methodological guideline for skin thickness measurement by ultrasound.

Seeing the unseen with superb microvascular imaging: Ultrasound depiction of normal dermis vessels

PURPOSE

Current color- and power-Doppler techniques cannot demonstrate vascularization of the dermis. Aim of this prospective study was to investigate whether the new superb vascular imaging (SMI) technique improves the ultrasound (US) depiction of dermis vessels in healthy volunteers. SMI was compared side-by-side to conventional power-Doppler (PD) imaging.

METHODS

Thirty adult subjects (18 men and 12 women, mean age 45 years old) were evaluated with US at level of five body areas: forehead, forearm, palm, buttock, and thigh. The vascular index (VI) was employed to objectively quantify the difference between SMI and PD imaging in terms of dermis flow amount.

RESULTS

Forehead VI was higher for SMI than for PD in 93% of cases, forearm VI was higher for SMI than for PD in 97% of cases, palm VI was higher for SMI than for PD in 87% of cases, buttock VI was higher for SMI than for PD in 100% of cases, thigh VI was higher for SMI than for PD in 100% of cases. SMI-detected vascular signals in 100% of the body areas. PD failed to show any flow signals from the forehead in 23% of cases, forearm in 37% of cases, palm in 33% of cases, buttock in 47% of cases, and thigh in 50% of cases.

CONCLUSION

SMI can demonstrate normal dermis vascularization whereas conventional PD cannot. SMI is a sensitive and promising technique in the study of dermis abnormalities, particularly when quantifying the disease activity is important.

Tofacitinib in the treatment of skin and musculoskeletal involvement in patients with systemic sclerosis, evaluated by ultrasound

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disease characterized by fibrosis of the skin and internal organs, autoimmunity-driven damage and vasculopathy. The current approved disease-modifying treatments have limited efficacy, and treatment is guided toward alleviating organ complications. Thus, there is an unmet need for discovering new effective treatment options. There is recent evidence that the JAK/STAT signaling pathway is markedly activated in SSc patients. To assess the efficacy and safety of tofacitinib (TOF) on skin and musculoskeletal involvement as compared to methotrexate (MTX) in systemic sclerosis (SSc). In this 52-week pilot study, 66 patients with SSc were enrolled: 33 patients received 5 mg of oral TOF twice a day; 33 received 10 mg of MTX weekly. The proportion of dcSSc and lcSSc patients was similar (dcSSc: 42% TOF group and 36% MTX group; lcSSc: 58% TOF group and 64% MTX group). The primary outcome was the change in the modified Rodnan skin score (mRSS). Secondary outcomes included ultrasound (US) skin thickness and musculoskeletal involvement (US10SSc score). Digital ulcers (DUs) and adverse events (AEs) were documented through the treatment. Both groups had similar characteristics and medians on the outcome measures at baseline. At week 52, the TOF median mRSS was significantly lower than the MTX (p < 0.001) with a mean reduction of 13 points versus MTX 2.57. The mean percent improvement in the TOF group was 44% higher than in the MTX group. TOF median US skin thickness was significantly lower than MTX (p < 0.001), with a mean reduction of 0.31 mm versus 0.075 mm in the MTX group. The US10SSc median score was significantly lower in the TOF group (p = 0.002); mean reduction of 10.21 versus 5.27 in the MTX group. Healing of DUs with no new occurrences was observed in the TOF group. There was no significant difference between the groups in the number of AEs from baseline to week 52. TOF showed greater efficacy than MTX in reducing mRSS, skin thickness and musculoskeletal involvement in SSc and a satisfactory safety profile.

Shear Wave Elastography for Assessment of Muscular Abnormalities Related to Systemic Sclerosis

RATIONALE AND OBJECTIVES

To assess muscular abnormalities related to systemic sclerosis (SSc) using shear wave elastography and correlate results with those of clinical tests.

MATERIALS AND METHODS

We evaluated 55 patients (mean age: 50.4 years; range: 18-88; 34 female) with SSc before treatment and choose muscle groups based on cutaneous involvement and functional impairment [forearms (9); thighs (41); thenar/hypothenar (5)]. We performed shear wave elastography in two orientations to access heterogeneity using virtual touch IQ and mean shear wave velocity values (SWV) and measured skin and fascia thickness. We compared SWVs to the modified Rodnan skin score (mRSS). Twenty-two healthy controls (mean age: 52.0; range: 19-88; 7 female) underwent the same protocol.

RESULTS

SWV pattern analysis (homogeneous vs heterogeneous) detected SSc with sensitivity/specificity/negative predictive value/positive predictive value0.79/0.81/0.91/0.62 in transverse and 0.75/0.18/0.91/0.56 in longitudinal orientation. In patients we found poor correlation between SWVs and mRSS but a cutoff of mRSSE = 20 separated them significantly (p < 0.01). Skin and muscle fascia were significantly thicker in patients vs. controls (p < 0.001).

CONCLUSION

SSc involves more than increased skin and fascial thickness which is not fully represented by mRSS. Elasticity differs in muscles with and without SSc. The former shows higher SWV and increased heterogeneity in transversal planes of muscular fibers.

The role of ultrasound in systemic sclerosis: On the cutting edge to foster clinical and research advancement

Ultrasound has been widely explored in systemic sclerosis in the clinical and research settings. Ultrasound allows a non-invasive and ionising radiation-free 'window' into this complex disease and is well-suited to repeated examinations. Ultrasound provides novel insights into the pathogenesis and measurement of disease in systemic sclerosis, including early (preclinical) internal organ involvement. The purpose of this review is to describe the role of ultrasound to foster clinical and research advancements in systemic sclerosis relating to (1) musculoskeletal, (2) digital ulcer, (3) lung disease and (4) skin disease. We also highlight unmet needs which much be addressed for ultrasound to assume a central role in systemic sclerosis clinical care and research.

HIGH FREQUENCY ULTRASONOGRAPHY: RELIABLE TOOL TO MEASURE SKIN FIBROSIS IN SSC? A systematic literature review and additional pilot study

OBJECTIVES

To investigate the reliability of high frequency ultrasound (HFUS) in measuring skin fibrosis in systemic sclerosis (SSc).

METHODS

First, a systematic review (according to PRISMA) was conducted to identify studies that documented HFUS' reliability in SSc as a primary outcome. Then, in an additional pilot study, the inter- and intra-rater reliability of two investigators performing HFUS for dermal thickness (DT) measurements in a standardised manner across all 17 areas of the modified Rodnan Skin Score was evaluated in a group of 59 SSc patients and descriptively in 44 healthy controls (HC). As an external validation, DT measurements by HFUS were performed in a separate group of 30 SSc patients by the same first and another third investigator.

RESULTS

The systematic review retained few (4/1719 unique records) small-scale studies, with mixed study populations (combining SSc and HC). The reported data herein are suggestive of the inter-/intra-rater reliability of HFUS (ICCs ranging 0.65-0.94/0.55-0.96, respectively). Additionally, in our pilot study, inter-/intra-rater reliability was good-to-excellent in both SSc groups and HC (ICCs ranging 0.70-0.97/0.70-0.98 and 0.65-0.95/0.63-0.96, respectively).

CONCLUSION

The identified small-scale studies were not only combining data from SSc and HC, they were also heterogeneous in terms of technical aspects (probes and frequency), image acquisition methods ([number of] areas assessed) and definitions used for skin thickness, which prevents drawing unequivocal conclusions. Despite these limitations, our standardized pilot study corroborated the findings in literature, paving the way for the applicability of HFUS as a reliable (complementary) tool to quantify skin fibrosis in SSc.

The Updated Role of Ultrasound in Assessing Dermatological Manifestations in Systemic Sclerosis

Systemic sclerosis (SSc), an autoimmune connective tissue disease, characterized by skin fibrosis, increased dermal thickness and microvascular involvement. Fibroblasts and myofibroblasts deposit excessive amounts of collagenous and non-collagenous extracellular matrix components in the skin. This leads to microvascular abnormalities and Raynaud's phenomenon, with painful digital ulcers (DU) at the fingertips adding to patient discomfort. The skin involvement and severity in SSc was evaluated by the Modified Rodnan skin score (mRSS). Although high-frequency ultrasound (HUS) has been widely researched in the study of skin thickness and DU in SSc, its adoption into clinical practice is not yet common. However, novel insights into the still relatively unknown disease pathogenesis in SSc and its evaluation may be provided by HUS, including early (pre-clinical) skin involvement. It may also be useful in both the evaluation and follow-up of DU. Indeed, it is a non-invasive, safe, inexpensive and reproducible method able to assess not only SSc patients' cutaneous structural changes, but also their vascular system changes. Moreover, several recent studies have reported that elastosonography (ES) is of use when investigating skin involvement in systemic sclerosis. This review aims at providing information as to role HUS and ES play in research advancements and the clinical perspectives in the evaluation of skin thickness and DU in SSc patients.

High-frequency ultrasound in clinical dermatology: a review

Background

Ultrasound was first introduced in clinical dermatology in 1979. Since that time, ultrasound technology has continued to develop along with its popularity and utility.

Main text summary

Today, high-frequency ultrasound (HFUS), or ultrasound using a frequency of at least 10 megahertz (MHz), allows for high-resolution imaging of the skin from the stratum corneum to the deep fascia. This non-invasive and easy-to-interpret tool allows physicians to assess skin findings in real-time, enabling enhanced diagnostic, management, and surgical capabilities. In this review, we discuss how HFUS fits into the landscape of skin imaging. We provide a brief history of its introduction to dermatology, explain key principles of ultrasonography, and review its use in characterizing normal skin, common neoplasms of the skin, dermatologic diseases and cosmetic dermatology.

Conclusion

As frequency advancements in ultrasonography continue, the broad applications of this imaging modality will continue to grow. HFUS is a fast, safe and readily available tool that can aid in diagnosing, monitoring and treating dermatologic conditions by providing more objective assessment measures.

Engineering Advanced In Vitro Models of Systemic Sclerosis for Drug Discovery and Development

Systemic sclerosis (SSc) is a complex multisystem disease with the highest case-specific mortality among all autoimmune rheumatic diseases, yet without any available curative therapy. Therefore, the development of novel therapeutic antifibrotic strategies that effectively decrease skin and organ fibrosis is needed. Existing animal models are cost-intensive, laborious and do not recapitulate the full spectrum of the disease and thus commonly fail to predict human efficacy. Advanced in vitro models, which closely mimic critical aspects of the pathology, have emerged as valuable platforms to investigate novel pharmaceutical therapies for the treatment of SSc. This review focuses on recent advancements in the development of SSc in vitro models, sheds light onto biological (e.g., growth factors, cytokines, coculture systems), biochemical (e.g., hypoxia, reactive oxygen species) and biophysical (e.g., stiffness, topography, dimensionality) cues that have been utilized for the in vitro recapitulation of the SSc microenvironment, and highlights future perspectives for effective drug discovery and validation.

How to perform high ultrasound examination of skin involvement among patients with systemic sclerosis - proposition of a unified protocol

Introduction

A fast and cheap method of skin assessment in systemic sclerosis (SSc) is an area of extensive research. Established in 1979, the Rodnan skin score is a palpation-based method used among clinicians. This method has some limitations, such as: examiner’s skills, subjective results, and no standardization. In the last few years researchers have been exploring ultrasound-based techniques as a possible tool for skin assessment among patients with SSc. The aim of the study is to develop a protocol of elastography-based skin imaging evaluation among patients with SSc.

Material and methods

Review of the literature and own experience.

Results

Proposition of elastography-based skin imaging protocol among patients with SSc.

Conclusions

The authors present a potential protocol of ultrasound-based examination of skin involvement among patients with SSc.

High-resolution ultrasound imaging of skin involvement in systemic sclerosis: a systematic review

To collect evidence on the application of ultrasound in skin assessment in patients with systemic sclerosis (SSc). The authors carried out a review of the literature via Pubmed MEDLINE database. The search terms were: skin imaging in systemic sclerosis, ultrasound skin imaging in patients with systemic sclerosis. The selection and analysis of articles were performed by two independent evaluators. The authors analyzed 10 studies characterizing 470 patients with systemic sclerosis. The patients were young adults, mainly women. The described methods of ultrasound were: ultrasound elastography (7.14%), ultra-high-frequency (7.14%) and B-mode ultrasonographic imaging (21.43%), high-frequency ultrasonography (21.43%), shear-wave elastography (21.43%) and others (21.43%). Skin measurements reported in the analyzed studies were: skin ultrasound in all studies, skin thickness (8 studies), skin elasticity (5 studies), skin stiffness (2 studies), subcutaneous tissue thickness (1 study). Ultrasound measurements were compared to different types of scales and measurements used in the description of disease progression. Ultrasound may be used in the clinical assessment of skin involvement in SSc. To the best of our knowledge, articles currently reporting the use of ultrasound in skin imaging show interesting ideas and provide basis for further research. Skin involvement in SSc assessed with ultrasound should be compared to skin biopsy. It is necessary to develop guidance for conducting skin measurements using ultrasound in patients with scleroderma. Currently, skin imaging in SSc is of limited clinical use due to a variety of methods and the lack of a standard operating procedure. The authors of analyzed studies suggested that high-frequency ultrasound provided a quantitative and reliable evaluation of dermal thickness in patients with SSc.

Hyperspectral imaging for skin assessment in systemic sclerosis: a pilot study

OBJECTIVE

Hyperspectral imaging (HSI) is a novel technology for obtaining quantitative measurements from transcutaneous spatial and spectral information. In patients with SSc, the severity of skin tightness is associated with internal organ involvement. However, clinical assessment using the modified Rodnan skin score is highly variable and there are currently no universal standardized protocols. This study aimed to compare the ability to differentiate between SSc patients and healthy controls using skin scores, ultrasound and HSI.

METHODS

Short-wave infrared light was utilized to detect the spectral angle mapper (SAM) of HSI. In addition, skin severity was evaluated by skin scores, ultrasound to detect dermal thickness and strain elastography. Spearman's correlation was used for assessing skin scores, strain ratio, thickness and SAM. Comparisons of various assessment tools were performed by receiver operating characteristic curves.

RESULTS

In total, 31 SSc patients were enrolled. SAM was positively correlated with skin scores and dermal thickness. In SSc patients with normal skin scores, SAM values were still significantly higher than in healthy controls. SAM exhibited the highest area under the curve (AUC: 0.812, P < 0.001) in detecting SSc compared with skin scores (AUC: 0.712, P < 0.001), thickness (AUC: 0.585, P = 0.009) and strain ratio by elastography (AUC: 0.522, P = 0.510). Moreover, the severity of skin tightness was reflected by the incremental changes of waveforms in the spectral diagrams.

CONCLUSION

SAM was correlated with skin scores and sufficiently sensitive to detect subclinical disease. HSI can be used as a novel, non-invasive method for assessing skin changes in SSc.

Durometry as an alternative tool to the modified Rodnan's skin score in the assessment of diffuse systemic sclerosis patients: a cross-sectional study

BACKGROUND

The reproducibility and reliability of the modified Rodnan's Skin Score (mRSS) are debated due to investigator-related subjectivity. Here, we evaluate if durometry correlates with mRSS in patients with diffuse systemic sclerosis (SSc).

METHODS

This cross-sectional study was conducted from December 2018 to June 2019, including 58 diffuse SSc patients. Two certified researchers, blind to each other's scores, performed the mRSS, followed by durometry at 17 predefined skin sites. For durometry and mRSS, individual scores per skin site were registered. Durometry and mRSS results measured by each researcher, as well as scores from different researchers, were compared. Skin thickness measurements from forearm skin biopsies were available in a subset of the patients, for comparisons. Statistical analyses included Cohen's Kappa Coefficient, Intraclass Correlation Coefficient, Kendall's Coefficient and Spearman's test.

RESULTS

Mean (standard deviation, SD) patient age was 44.8 (12.9) years, and 88% were female. Inter-rater agreement varied from 0.88 to 0.99 (Intraclass correlation coefficient) for durometry, and 0.54 to 0.79 (Cohen's Kappa coefficient) for mRSS, according to the specific evaluated sites. When data were compared with skin thickness assessed in forearm biopsies, durometry correlated better with skin thickness than mRSS.

CONCLUSION

Durometry may be considered as an alternative method to quantify skin involvement in patients with diffuse SSc. The strong inter-rater agreement suggests that the method may be useful for the assessment of patients by multiple researchers, as in clinical trials.

Ultrasound assessment of skin thickness and stiffness: the correlation with histology and clinical score in systemic sclerosis

Background

Ultrasound is a useful tool to evaluate and quantify skin lesions. Few studies have assessed the criterion validity of skin ultrasound in systemic sclerosis (SSc). The aims of the study were to investigate skin thickness and stiffness using ultrasound and shear wave elastography (SWE) in SSc and to validate skin ultrasound measurements against histological skin thickness.

Methods

A total of 22 patients with diffuse cutaneous SSc (dcSSc), 22 with limited cutaneous SSc (lcSSc), and 22 age- and gender-matched healthy controls were enrolled. Skin thickness and stiffness were measured by B-mode ultrasound with SWE imaging on the bilateral fingers and hands. Additional ultrasound evaluation was carried out in 13 patients (9 dcSSc and 4 lcSSc) on their dorsal forearms, followed by skin biopsy conducted in the same skin areas. Correlations between ultrasound measurements and histological skin thickness and modified Rodnan skin score (mRSS) were investigated using Spearman’s correlation.

Results

Compared with controls, ultrasound-measured skin thickness and skin stiffness were significantly higher in patients with SSc (p < 0.001) and even higher in those with dcSSc. No clear correlation could be established between ultrasound-determined skin thickness and stiffness at the same site. Ultrasound-measured skin thickness correlated well with histological skin thickness (r = 0.6926, p = 0.009). A weaker association was also observed between histological skin thickness and local mRSS (r = 0.5867, p = 0.050).

Conclusions

Ultrasound is a reliable tool for quantifying skin involvement in SSc. Ultrasound-measured skin thickness showed good agreement with histological skin thickness.

Novel Imaging Strategies in Systemic Sclerosis

PURPOSE OF REVIEW

Imaging modalities such as computed tomography, ultrasound, magnetic resonance imaging, and molecular imaging are being used to evaluate for disease in systemic sclerosis (SSc) patients. Here, we review novel imaging strategies to detect organ and vascular complications of SSc and novel imaging techniques for assessing interstitial lung disease and pulmonary hypertension in other conditions that may have further applicability to SSc.

RECENT FINDINGS

Imaging techniques can be used to identify disease in the lungs, pulmonary vascular system, heart, skin, vascular tissue, and gastrointestinal tract of SSc patients. These show promise in detecting early disease, many without the use of ionizing radiation. Novel imaging techniques in patients with SSc can be used to detect disease in multiple susceptible organs. These imaging strategies have potential for early disease detection, as well as potential for incorporation into clinical trials to accelerate the development of SSc therapies.

High-throughput quantitative histology in systemic sclerosis skin disease using computer vision

BACKGROUND

Skin fibrosis is the clinical hallmark of systemic sclerosis (SSc), where collagen deposition and remodeling of the dermis occur over time. The most widely used outcome measure in SSc clinical trials is the modified Rodnan skin score (mRSS), which is a semi-quantitative assessment of skin stiffness at seventeen body sites. However, the mRSS is confounded by obesity, edema, and high inter-rater variability. In order to develop a new histopathological outcome measure for SSc, we applied a computer vision technology called a deep neural network (DNN) to stained sections of SSc skin. We tested the hypotheses that DNN analysis could reliably assess mRSS and discriminate SSc from normal skin.

METHODS

We analyzed biopsies from two independent (primary and secondary) cohorts. One investigator performed mRSS assessments and forearm biopsies, and trichrome-stained biopsy sections were photomicrographed. We used the AlexNet DNN to generate a numerical signature of 4096 quantitative image features (QIFs) for 100 randomly selected dermal image patches/biopsy. In the primary cohort, we used principal components analysis (PCA) to summarize the QIFs into a Biopsy Score for comparison with mRSS. In the secondary cohort, using QIF signatures as the input, we fit a logistic regression model to discriminate between SSc vs. control biopsy, and a linear regression model to estimate mRSS, yielding Diagnostic Scores and Fibrosis Scores, respectively. We determined the correlation between Fibrosis Scores and the published Scleroderma Skin Severity Score (4S) and between Fibrosis Scores and longitudinal changes in mRSS on a per patient basis.

RESULTS

In the primary cohort (n = 6, 26 SSc biopsies), Biopsy Scores significantly correlated with mRSS (R = 0.55, p = 0.01). In the secondary cohort (n = 60 SSc and 16 controls, 164 biopsies; divided into 70% training and 30% test sets), the Diagnostic Score was significantly associated with SSc-status (misclassification rate = 1.9% [training], 6.6% [test]), and the Fibrosis Score significantly correlated with mRSS (R = 0.70 [training], 0.55 [test]). The DNN-derived Fibrosis Score significantly correlated with 4S (R = 0.69, p = 3 × 10- 17).

CONCLUSIONS

DNN analysis of SSc biopsies is an unbiased, quantitative, and reproducible outcome that is associated with validated SSc outcomes.

Applicability of shear wave elastography for the evaluation of skin strain in systemic sclerosis

The assessment of skin fibrosis is vital for the diagnosis and monitoring of treatment in the systemic sclerosis (SSc)-a severe autoimmune disease. The elastography is a technique of skin fibrosis assessment through the evaluation of skin strain. We compared the efficacy of the shear wave elastography (SWE) and commonly used modified Rodnan skin score (RSS) in skin fibrosis assessment in SSc. The study included 40 SSc patients and 28 healthy individuals, with the exclusion of individuals with other skin/autoimmune diseases. Skin thickness using RSS and skin strain using SWE were assessed in the same 20 body localizations. Subjects' informed consent and the bioethics committee approval were obtained. Elastographic skin strain correlated positively with both partial and overall RSS values, with strong positive correlation (r ≥ 0.75) for hands and fingers localizations in particular. In SSc patients with normal RSS values, the elastographic strain was significantly higher than in healthy controls. Elastographic strain of fingers' skin evaluated in SWE is highly accurate for distinguishing SSc patients (sensitivity 0.897-0.923, specificity 0.929-0.964, positive predictive value 0.946-0.973, negative predictive value 0.867-0.900). ESW results are substantially more reproducible than those of RSS examination (intraclass correlation coefficients: 0.987 vs. 0.941). The shear wave elastography is more reproducible and has higher sensitivity than RSS in the evaluation of skin condition in SSc, especially in case of changes non-detectable on physical evaluation, indicating it might become a useful tool in SSc diagnosis.

Investigation of using very high-frequency ultrasound in the differential diagnosis of early-stage pemphigus vulgaris vs seborrheic dermatitis

Background

Early‐stage pemphigus vulgaris (PV) often manifests as erythema alone. We hypothesized that very high‐frequency ultrasonography (VHFUS) features could simplify the differential diagnosis of early‐stage pemphigus vulgaris versus seborrheic dermatitis (SD).

Materials and Methods

Fourteen patients with SD or early‐stage PV were recruited from our outpatient clinic during 2016‐2019. We used 50‐MHz VHFUS to image the erythema on the patients’ scalp, face, chest, and back and retrospectively evaluated their ultrasonographic features.

Results

Very high‐frequency ultrasonography images of early‐stage PV showed enhanced epidermal echo (8/14, 57%), linear or oval intra‐epidermal hypoechoic/anechoic areas (12/14, 86%), linear anechoic areas at the dermal‐epidermal junction (14/14, 100%), reduced echo of superficial to whole dermis (9/14, 64%), and slightly increased dermal thickness (14/14, 100%). The intra‐epidermal hypoechoic/anechoic bands (100%) showed the greatest specificity. VHFUS images of SD showed enhanced epidermal echo (7/14, 50%), epidermal unevenness (7/14, 50%), linear anechoic bands at the dermal‐epidermal junction (8/14, 57%), reduced middle dermis echo (10/14, 71%), and slightly increased dermal thickness (10/14, 71%). The epidermal unevenness (100%) had the greatest specificity. There was a significant difference (P < .05) between early‐stage PV and SD regarding the proportion of linear intraepithelial hypoechoic/anechoic bands and linear anechoic areas at the dermal‐epidermal junction.

Conclusions

Early‐stage PV and SD have relatively specific VHFUS erythematous manifestations. Intra‐epidermal hypoechoic/anechoic bands for early‐stage PV and epidermal unevenness for SD were most specific. VHFUS contributes to the differential diagnosis of PV and SD by highlighting their features, that is, intra‐epidermal hypoechoic/anechoic bands and linear anechoic areas at the dermal‐epidermal junction.

Correlation between circulating fibrocytes and dermal thickness in limited cutaneous systemic sclerosis patients: a pilot study

The objective is to detect any possible correlation between the modified Rodnan skin score (mRSS) and dermal thickness (DT) measured by skin high-frequency ultrasound (US) and the percentage of circulating fibrocytes in patients with limited cutaneous systemic sclerosis (lcSSc). Eight lcSSc patients and five healthy subjects (control group, CNT) were enrolled. The skin involvement was evaluated by mRSS and US (18 and 22 MHz probes) in all 13 subjects in the 17 standard skin areas evaluated by mRss. Circulating fibrocytes were isolated from the peripheral blood mononuclear cells (PBMCs) of all lcSSc patients and the CNT group to analyze their percentage at baseline time (T0) when the experiments started with PBMCs' isolation and collection and after 8 days of culture (T8). Non-parametric tests were used for the statistical analysis. A positive correlation between the percentage of circulating fibrocytes at T0, mRSS (p = 0.04 r = 0.96), and DT-US, evaluated by the 22 MHz and the 18 MHz probes (p = 0.03, r = 0.66 and p = 0.05, r = 0.52, respectively), was observed in lcSSc patients. Conversely, at T8, there was no correlation (p > 0.05) between these parameters in lcSSc group. In the CNT group, no correlations between mRSS or DT-US and the percentage of circulating fibrocytes were observed both at T0 and T8. The study shows the presence of a significant relationship between the percentage of circulating fibrocytes and DT, as evidenced by both mRSS and US, in limited cutaneus SSc. This observation may well suggest the reasonable hypothesis of a crucial contribution of circulating fibrocytes to skin fibrosis progression, which might be considered as further biomarkers.