Objective. To evaluate the interobserver agreement of ultrasonographic assessment of finger and toe joints in patients with rheumatoid arthritis (RA) by 2 investigators with different medical backgrounds.Methods. Ultrasonography and clinical examination were performed on 150 small joints of 30 patients with active RA. A General Electric LOGIQ 500 ultrasound unit with a 7-13-MHz linear array transducer was used. In each patient, 5 preselected small joints (second and third metacarpophalangeal, second proximal interphalangeal, first and second metatarsophalangeal) were examined independently on the same day by 2 ultrasound investigators (an experienced musculoskeletal radiologist and a rheumatologist with limited ultrasound training). Joint effusion, synovial thickening, bone erosions, and power Doppler signal were evaluated in accordance with an introduced 4-grade semiquantitative scoring system, on which the investigators had reached consensus prior to the study.Results. Exact agreement between the 2 observers was seen in 91% of the examinations with regard to bone erosions, in 86% with regard to synovitis, in 79% with regard to joint effusions, and in 87% with regard to power Doppler signal assessments. Conclusion. An experienced radiologist and a rheumatologist with limited ultrasound training achieved high interobserver agreement rates for the identification of synovitis and bone erosions, using an introduced semiquantitative scoring system for ultrasonography of finger and toe joints in RA. Signs of inflammation were more frequently detected with ultrasound than with clinical examination. Ultrasonography may improve the assessment of RA patients by radiologists and rheumatologists.

Conclusion. US enables detection and grading of destructive and inflammatory changes in the MTP joints of patients with RA. By comparison with MRI, US was found to be markedly more sensitive and accurate than clinical examination and conventional radiography. Considering the early and frequent involvement of the MTP joints, evaluation of these joints by US may be of major clinical importance in RA.

ObjectivesTo develop a consensus-based ultrasound (US) definition and quantification system for synovitis in rheumatoid arthritis (RA).MethodsA multistep, iterative approach was used to: (1) evaluate the baseline agreement on defining and scoring synovitis according to the usual practice of different sonographers, using both grey-scale (GS) (synovial hypertrophy (SH) and effusion) and power Doppler (PD), by reading static images and scanning patients with RA and (2) evaluate the influence of both the definition and acquisition technique on reliability followed by a Delphi exercise to obtain consensus definitions for synovitis, elementary components and scoring system.ResultsBaseline reliability was highly variable but better for static than dynamic images that were directly acquired and immediately scored. Using static images, intrareader and inter-reader reliability for scoring PD were excellent for both binary and semiquantitative (SQ) grading but GS showed greater variability for both scoring systems (κ ranges: −0.05 to 1 and 0.59 to 0.92, respectively). In patient-based exercise, both intraobserver and interobserver reliability were variable and the mean κ coefficients did not reach 0.50 for any of the components. The second step resulted in refinement of the preliminary Outcome Measures in Rheumatology synovitis definition by including the presence of both hypoechoic SH and PD signal and the development of a SQ severity score, depending on both the amount of PD and the volume and appearance of SH.ConclusionA multistep consensus-based process has produced a standardised US definition and quantification system for RA synovitis including combined and individual SH and PD components. Further evaluation is required to understand its performance before application in clinical trials.

Objective To evaluate the effectiveness of power Doppler ultrasonography (PDUS) for assessing inflammatory activity in the metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA), using dynamic magnetic resonance imaging (MRI) as a reference method. Methods PDUS and dynamic MRI were performed on 54 MCP joints of 15 patients with active RA and on 12 MCP joints of 3 healthy controls. PDUS was performed with a LOGIQ 500 unit by means of a 7–‐13‐MHz linear array transducer. Later the same day, MRI was performed with a 1.0T MR unit. A series of 24 coronal T1‐weighted images of the second through the fifth MCP joints was obtained, with intravenous injection of gadolinium diethylenetriaminepentaacetic acid after the fourth image (dynamic MRI). From the MR images, the rate of early synovial enhancement (RESE; defined as the relative enhancement per second during the first 55 seconds postinjection) was calculated and compared with the flow signal on PDUS, which was scored as present or absent. Results In RA patients, flow signal on PDUS was detected in 17 of 54 MCP joints examined. Postcontrast MR images revealed an RESE of ≥1.0%/second in 18 of 54 RA MCP joints. PDUS showed no flow in 47 of 48 MCP joints with an RESE of <1.0%/second and revealed flow in 16 of 18 MCP joints with an RESE of ≥1.0%/second. Using dynamic MRI as a reference, PDUS had a sensitivity of 88.8% and a specificity of 97.9%. Conclusion PDUS was reliable for assessing inflammatory activity in the MCP joints of RA patients, using dynamic MRI as the standard. PDUS and clinical assessment of joint swelling/tenderness were only weakly correlated.