I. Janta

OBJECTIVE: High frequency ultrasound allows visualization of epidermis, dermis and hypodermis, precise measurement of skin thickness, as well as assessment of skin oedema, fibrosis and atrophy. The aim of this pilot cross-sectional observational study was to assess the performance and multiobserver variability of ultra-high-frequency (UHF) (50 MHz) ultrasound (US) in measuring skin thickness as well as the capacity of UHF-derived skin features to differentiate SSc patients from healthy controls. METHODS: Twenty-one SSc patients (16 limited and five diffuse SSc) and six healthy controls were enrolled. All subjects underwent US evaluation by three experts at three anatomical sites (forearm, hand and finger). Dermal thickness was measured and two rectangular regions of interest, one in dermis and one in hypodermis, were established for texture feature analysis. RESULTS: UHF-US allowed a precise identification and measurement of the thickness of the dermis. The dermal thickness in the finger was significantly higher in patients than in controls (P < 0.05), while in the forearm it was significantly lower in patients than in controls (P < 0.001). Interobserver variability for dermal thickness was good to excellent [forearm intraclass correlation coefficient (ICC) = 0.754; finger ICC = 0.699; hand ICC = 0.602]. Texture computed analysis of dermis and hypodermis was able to discriminate between SSc and healthy subjects (area under the curve >0.7). CONCLUSION: These preliminary data show that skin UHF-US allows a very detailed imaging of skin layers, a reliable measurement of dermal thickness, and a discriminative capacity between dermis and hypodermis texture features in SSc and healthy subjects.

OBJECTIVE: The objective of this study was to compare disease activity assessed by the patient, the physician and musculoskeletal US in patients with RA in clinical remission. METHODS: We evaluated 69 patients with RA in clinical remission according to their attending rheumatologist. Tenderness and swelling in 28 joints were blindly assessed by patients and physicians. The presence of B-mode and Doppler synovitis was blindly investigated in the above joints. The DAS28 and Simplified Disease Activity Index (SDAI) were calculated. RESULTS: The percentage of patients in remission according to the self-derived DAS28 (26.1%) was significantly less than that according to the physician-derived DAS28 (52.2%) (P < 0.0005). There was no significant difference in the percentage of patients in remission according to the self-derived SDAI (14.5%) and the physician-derived SDAI (11.6%) (P = 0.172). We found moderate agreement between the patient-derived and physician-derived DAS28 and SDAI [intraclass correlation coefficient (ICC) = 0.620 and ICC = 0.678, respectively]. Agreement between patient and physician was better for the tender joint count (TJC; ICC = 0.509) than for the swollen joint count (SJC; ICC = 0.279). The mean (S.D.) count for B-mode synovitis [4.09 (3.25)] was significantly greater than the SJC assessed by both the patient and physician [2 (3.71) and 1.42 (2.03), respectively] (P < 0.0005 and P = 0.033, respectively). We found moderate agreement between the physician-assessed SJC and the joint count for Doppler synovitis (ICC = 0.528). CONCLUSION: Patient-assessed and physician-assessed overall RA activity showed acceptable agreement. Patient self-assessment overestimated disease activity determined by the DAS28. At the patient level, physician-assessed joint swelling showed an acceptable concordance with Doppler US synovitis.