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.

Innovations in the Assessment of Primary and Secondary Raynaud's Phenomenon.

Objectives: Raynaud's phenomenon (RP) is characterized by intense vasospasm of the digital arteries that causes characteristic color changes in fingers. There are two main types of RP: Primary RP (PRP) and Secondary RP (SRP). PRP is a benign condition. Whilst SRP is associated with several connective tissue diseases (CTD), in particular systemic sclerosis (SSc). The objectives of this report were: to present a short review on morphological (nailfold videocapillaroscopy, NVC) and functional techniques (laser tools and thermography) that allow for a correct diagnosis and treatment of RP and to investigate blood perfusion (BP) by laser speckle contrast analysis (LASCA) in different skin areas of hands and face in PRP, SRP to SSc, and healthy subjects (CNT). Methods: 31 PRP patients (LeRoy criteria), 70 SRP to SSc (ACR/EULAR criteria) and 68 CNT were enrolled. BP was assessed by LASCA at the level different areas of hands and face. NVC was performed to distinguish between PRP and SRP, and to detect the proper pattern of nailfold microangiopathy in SSc patients. Results: Both PRP and SRP showed a statistically significant lower BP than CNT at the level of fingertips (p < 0.0001), periungual (p < 0.0001), palmar aspect of 3rd finger (p < 0.0001), and palm areas (p < 0.0001). Moreover, BP was significantly lower in PRP than in SRP to SSc with the "Early" pattern of microangiopathy in the same areas as above (p < 0.04). Conclusion: By considering a small cohort of patients, BP of hands was found lower in PRP than in SSc patients with the "Early" NVC pattern of microangiopathy.

Ultrasonography for the Assessment of Skin in Systemic Sclerosis: A Systematic Review.

OBJECTIVE: To identify and synthesize the best available evidence on the use of ultrasound to assess skin involvement in systemic sclerosis (SSc). METHODS: We conducted a systemic review of the literature on PubMed Medline and Embase, using the vocabulary terms ("systemic sclerosis OR scleroderma") AND ("ultrasonography" OR "elasticity imaging techniques") AND ("skin" OR "dermis"). Two independent reviewers selected articles, collected data from studies, and carried out a manual search of the references from the studies included. This search was further enhanced by a review of bibliographic references extrapolated from these studies. The quality of the evidence was assessed by the Effective Public Health Practice Project system. RESULTS: A total of 30 studies were identified, enrolling 1,171 SSc patients, predominantly middle-aged (mean age 55.5 years) females (88.8%). The ultrasound skin measurements that were reported included thickness in 28 studies and/or echogenicity (7 studies), and/or stiffness (6 studies), and/or vascularity (1 study). The main comparator was the global and site-specific modified Rodnan skin thickness score. Reported interrater and intrarater reproducibility appeared to be excellent, but this reproducibility was assessed by a small number of studies. Moreover, there were no published evaluations of construct or criterion validity of skin ultrasound assessment. The responsiveness to change of ultrasound elastography has not been assessed. CONCLUSION: Published reports have strong limitations and are highly heterogeneous, hindering the evidence to support the use of skin ultrasound assessment in clinical practice. Further studies, with modern devices and appropriate methodology, are needed to establish the real value of skin ultrasound assessment in the early diagnosis and monitoring of SSc patients.

Automated assessment of absolute nailfold capillary number on videocapillaroscopic images: Proof of principle and validation in systemic sclerosis.

BACKGROUND: Absolute nailfold capillary number should be a putative biomarker in selected rheumatic diseases but could be time-consuming and not highly repeatable. OBJECTIVE: To validate an automated software for absolute nailfold capillary number and density evaluation, on NVC images in SSc. METHODS: An automated software to count nailfold capillary number (AUTOCAPI) had been constructed, through an exploratory image set. Subsequently, application rules have been created to define the ROI in NVC images, through a training images set. The software reliability was assessed through calculation of the ICC between automatic and manual counting, by four independent observers, on the same NVC images. RESULTS: The following ICC's were obtained per observer, for the patients with SSc (40 images), the healthy (20 images), and the PRP subgroups (20 images), respectively: 0.94, 0.81, and 0.62 (observer 1); 0.94, 0.91, and 0.67 (observer 2); 0.88, 0.56, and 0.64 (observer 3); and 0.88, 0.85, and 0.85 (observer 4). CONCLUSIONS: The validation of an automated software for measuring absolute nailfold capillary number and density in SSc was achieved. The integration into the pre-existing imaging software should make the assessment of the capillary number in NVC easier, quicker, and standardized.