Background Involvement of the wrist joint is very frequent in approximately 70% of rheumatoid arthritis (RA) patients. Magnetic resonance imaging (MRI) benefits of high sensitivity and specificity in the evaluation of RA joints make it a worthy surrogate gold standard in diagnosis. Availability of musculoskeletal ultrasound (MSUS)with low costs and also patient friendly manner, might be a very good diagnostic substitute for screening. Conventional radiography(CR) can provide only indirect information on synovial inflammation, however, the technique is insensitive to early bone damage.
Objectives We aimed to examine whether MSUS can provide information on signs of inflammation and destruction in RA wrist joint in early and late disease and compare the findings with MRI and CR.
Methods Eighty RA patients with wrist joint involvement were selected from those attending Rheumatology outpatient’s clinics of Assiut and Alazhar university hospitals. Patients were then classified into two groups according to the disease duration as follows:Group A: included patients with early RA (≤ 2 years). Group B: included patients with long standing RA (≤ 2 years). All patients were subjected to complete history taking and clinical examination with assessment of disease activity according to DAS-28 in addition to the comparative CR, MSKUS and MRI.
Results MSUS is more sensitive than CR in the detection of erosions both in early and late RA however the sensitivity increased significantly in late disease (0.45 versus 0.63). The ability of the three imaging modalities in detecting erosions was found to be more remarkable in the group of late RA with P value ˂0.001. With MRI as the reference, the sensitivity and specificity of MSUS for all studied cases collectively were 76.4% and 72% respectively.
In the group of early RA (Group A), the sensitivity and specificity of MSUS were 45.5% and 70% respectively, while those for CR were 18.2% and 100% respectively. In (Group B), the sensitivity of MSUS was 84% while the specificity was 80%. For CR the sensitivity was 63% while the specificity was 80%. In the detection of soft tissue abnormality, the sensitivity and specificity of MSUS for all studied cases were 85.2% and 89.5% respectively with high agreement between MSUS and MRI (Kappa = 0.66). In the group of early RA, the sensitivity and specificity of MSUS were 88% and 83.3% respectively. Whereas, they were 83.3% and 92.3% in the group of established RA. the detection of soft tissue abnormality was significantly correlated with disease activity in patients of group (B) with p value of 0.01 for MRI and 0.03 for MSUS.
Musculoskeletal Ultrasonography is a sensitive tool and comparable to MRI in the diagnosis of bone erosions and joint inflammation in early and late rheumatoid wrist.
It is more sensitive than conventional radiography in the detection of erosions with increasing sensitivity on long standing disease.
It is also more sensitive than clinical examination in the detection of inflamed wrist joint in both early and long standing RA.
Musculoskeletal US should become of increasing relevance to rheumatologists, and be widely applied in daily clinical practice.
Disclosure of Interest None Declared