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

Abstract

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.

Hematopoietic stem cell transplantation for systemic sclerosis: Brazilian experience

“…This is a consistent finding across studies on HSCT for SSc, as skin thickness decreases significantly, especially in the first 6 months after HSCT [1,2,5,20,24,32]. Rodnan's score has good correlation with dermal thickness, evaluated both through skin biopsies and ultrasound [34,35]. In fact, histopathological analyses show a decline in dermal thickness at 1 year post-transplantation, which is not different from that of healthy controls at 5 years after HSCT [5].…”

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

“…According to several authors, the mRSS correlated more positively with skin stiffness than with its thickness [ 1 , 8 , 9 , 13 , 15 , 17 ]; therefore, it is important to test both modalities among a larger group of patients. Interestingly, some authors reported a significant correlation between mRSS and US measurements in the phalanx area [ 14 ].…”

“…Studies suggest that skin thickness (ST) measured with a US-based modality can replace mRSS examination [1,[9][10][11][12]. This is mainly because of the positive correlation between skin stiffness and the mRSS in these studies [1,11,[13][14][15][16][17][18][19].…”

“…Skin involvement assessed with the mRSS correlates with skin stiffness and thickness. According to personal experience and analyzed studies the authors suggest the use of ultrasound-based techniques, in particular high-frequency ultrasound and shear-wave elastography [9,10,13,14,[17][18][19][20].…”

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

“…in the skin stiffness at all Rodnan sites (p-value ≤ 0.001) (except in the fingers), in SSc patients - The % of the reduction in skin stiffness varied in the different Rodnan sites and in different phases of the disease. - There was a statistically significant change in the local Rodnan score only in the upper arm (p-value = 0.046) and forearm (p-value= 0.026) Chen (2020) 44 CC 44 (22dcSSc, 22lcSSc) 22 - Both Ultrasound-ST and skin stiffness were significantly higher in SSc patients (p-value < 0.001) and even higher in those with dcSSc, than in controls. - No clear correlation could be established between ultrasound-determined skin thickness and stiffness at the same site.…”