Background Systemic sclerosis (SSc) is a systemic inflammatory autoimmune disease characterized by fibrosis and involvement in the small vessels, skin, joints, and multiple internal organs. Although joint involvement is common in SSc, its cause is poorly understood. Radiographic erosive bone changes have been reported in some SSc patients and these changes have been attributed to overlap rheumatoid arthritis (RA).
Objectives Magnetic resonance imaging (MRI) can identify and characterize synovitis, effusion, erosion and joint damages much more precisely than radiographs. We previously reported that radiographic abnormalities were detected in 21.7% of patients with SSc (EULAR 2008). The aim of this study was to evaluate hand/wrist joints involvement in patients with SSc using MRI.
Methods Thirty-two patients (28 female, mean age 70.6±8.37 years) fulfilling the 2013 ACR/EULAR criteria for SSc who have a history of the hand/wrist joint pain were included after agreement to the examination of MRI. MRI examination was performed to symptomatic hand/wrist in all patients. MRI was performed on a 1.5 Tesla MRI device with dedicated surface coils (EXCELART Vantage F2-Edition; Toshiba Medical Systems, Corporation, Tokyo, Japan). Non-enhanced axial and coronal T1-weighted spin-echo imaging, T2-weighted spin-echo imaging and T2*-weighted spin-echo imaging were performed in all patients. MRI images were independently assessed by a radiologist and qualitatively analyzed for the presence of joints space narrowing, synovial fluid, synovial thickness, erosion, subchondral cysts and carpal bones necrosis. All SSc patients were evaluated for the presence of esophageal, renal, joint involvement and items of 2013 ACR/EULAR criteria for SSc. We also analyzed rheumatoid factor (RF) and anti-CCP antibodies (ACPA) in serum from SSc patients.
Results Twenty-seven out of 32 SSc patients (84.4%) were detected MRI abnormalities (joint space narrowing 28.1%, synovial fluid 65.6%, synovial thickness 47.0%). Eight out of 32 patients (12.1%) had joint features similar to those seen in RA such as erosion (7 patients) and subchondral cysts (2 patients). Fifteen out of 32 SSc patients (46.9%) had carpal bones necrosis, which is less frequently observed in RA patients. Serum RF or ACPA positive patients were 40.6% or 31.3% in all SSc patients, respectively. The prevalence of joint space narrowing, synovial fluid and synovial thickness was not differed between ACPA positive SSc patients (ACPA+/SSc) and ACPA negative SSc patients (ACPA-/SSc) by MRI. However, erosions and subchondral cysts were found more frequently in ACPA+/SSc than in ACPA-/SSc (50.0% vs 9.1%, p=0.01, 20.0% vs 0.0%, p=0.03). In contrast, carpal bones necrosis was found more frequently in ACPA-/SSc than in ACPA+/SSc (59.1 vs 20.0%, p=0.04). The prevalence of proximal scleroderma (73.3 vs 35.3%, p=0.045) and abnormal nailfold capillaries (100.0 vs 76.5%, p=0.031) was higher in SSc patients with carpal bones necrosis than in SSc patients without carpal bone necrosis.
Conclusions These results indicate that MRI is very useful for the evaluation of hand/wrist joint lesions in SSc patients. Carpal bones necrosis is characteristic joint lesions in SSc, suggesting that microvascular damage may trigger carpal bones necrosis.
Disclosure of Interest None declared