Quantitative power Doppler signal assessment in the subchondral bone region of the metacarpophalangeal joint is an effective predictor of radiographic progression in the hand of rheumatoid arthritis: a pilot study.

Ultrasonography is useful for assessment of synovitis in the hand of rheumatoid arthritis (RA) patients. The aim of this study was to investigate the predictive value of the quantitative power Doppler (PD) signal assessment in the subchondral bone region of the metacarpophalangeal (MCP) joint in patients with RA showing radiographic progression of the hand by comparing with those of previously reported scoring systems. Twenty-two patients (20 women) with RA who underwent power Doppler ultrasonography (PDUS) of the bilateral one to five MCP joints at baseline were included in the study. Radiography of both hands was performed at baseline and at 1 year. PDUS of the synovial space was evaluated according to semi-quantitative scoring (0-3) and quantitative measurement (0-100%). The PD signal in the subchondral bone region was qualitatively (0, 1) and quantitatively (mm2) assessed. The performance of PDUS assessment was compared using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve and the risk ratio (RR). As a predictor for radiographic progression, the quantitative PD signal assessment in the subchondral bone region (AUC = 0.842, p < 0.01) was equivalent to quantitative vascularity (AUC = 0.817, p < 0.05) and semi-quantitative scoring (AUC = 0.754, p < 0.05). As for the RR of the PD signal in the subchondral bone region for radiographic progression, the quantitative PD signal assessment was 5.40 (p < 0.01), whereas the qualitative PD signal assessment was 1.60 (p = 0.204). Quantitative PD signal assessment in the subchondral bone region can predict radiographic progression in the hand of RA patients.

Consensus-based identification of factors related to false-positives in ultrasound scanning of synovitis and tenosynovitis.

INTRODUCTION: We aimed to identify causes of false-positives in ultrasound scanning of synovial/tenosynovial/bursal inflammation and provide corresponding imaging examples. METHODS: We first performed systematic literature review to identify previously reported causes of false-positives. We next determined causes of false-positives and corresponding example images for educational material through Delphi exercises and discussion by 15 experts who were an instructor and/or a lecturer in the 2013 advanced course for musculoskeletal ultrasound organized by Japan College of Rheumatology Committee for the Standardization of Musculoskeletal Ultrasonography. RESULTS: Systematic literature review identified 11 articles relevant to sonographic false-positives of synovial/tenosynovial inflammation. Based on these studies, 21 candidate causes of false-positives were identified in the consensus meeting. Of these items, 11 achieved a predefined consensus (≥ 80%) in Delphi exercise and were classified as follows: (I) Gray-scale assessment [(A) non-specific synovial findings and (B) normal anatomical structures which can mimic synovial lesions due to either their low echogenicity or anisotropy]; (II) Doppler assessment [(A) Intra-articular normal vessels and (B) reverberation)]. Twenty-four corresponding examples with 49 still and 23 video images also achieved consensus. CONCLUSIONS: Our study provides a set of representative images that can help sonographers to understand false-positives in ultrasound scanning of synovitis and tenosynovitis.

Structural deterioration of finger joints with ultrasonographic synovitis in rheumatoid arthritis patients with clinical low disease activity.

OBJECTIVE: In this study we investigated the relationship between synovial vascularity (SV) and structural alteration of finger joints in patients with RA and long-term sustained clinical low disease activity (CLDA). METHODS: RA patients with CLDA of >2 years (minimum 1 year of CLDA for study entry plus 1 year of observation) were analysed. Quantitative SV values were sequentially measured in each finger joint using power Doppler ultrasonography (0, 8, 20 and 52 weeks). Radiological progression of local finger joints was evaluated according to the Genant-modified Sharp score (0-52 weeks). RESULTS: Of the 25 patients enrolled, 15 patients were finally analysed after excluding 10 patients who failed to maintain CLDA during the observational period. Changes in radiological progression of MCP and PIP joints with positive SV were significantly greater than those in joints with negative SV. Joint space narrowing (JSN) was strongly related to structural alteration of finger joints. In joints with positive SV, changes in structural alteration did not relate to total SV values, which reflect total exposure to inflammation in an observational period. CONCLUSION: Even in patients with a long period of CLDA, finger joints with positive SV showed structural alteration, especially in the progression of JSN. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry, http://www.umin.ac.jp/ctr/, UMIN000007305.

Analysis of the factors which influence the measurement of synovial power Doppler signals with semi-quantitative and quantitative measures - a pilot multicenter exercise in Japan.

OBJECTIVES: This pilot multicenter exercise aimed to evaluate the inter-observer reproducibility of synovial power Doppler (PD) signals in rheumatoid arthritis (RA) patients and to determine the factors influencing the measurements. METHODS: Two representative RA patients were assessed by four independent experienced sonographers. The influence of machine difference, deterioration of the transducer and pulse repetition frequency (PRF) on the assessment of synovial PD signals was investigated. RESULTS: Intra-class correlation coefficient (ICC) for the scanner-reader reproducibility of semi-quantitative PD score was high (0.867). ICC for the inter-scanner reproducibility of synovial PD pixel count was higher than that of semi-quantitative PD score. The assessment of PD signals significantly differed between two machines with quantitative measurements but did not with semi-quantitative score. The assessment of PD signals with a deteriorated transducer was much less sensitive than that with an intact one. The semi-quantitative scores for PD signals were comparable between three different PRFs (500/800/1,300 Hz), whereas the pixel count was significantly lower with the highest one in the knee joint. CONCLUSIONS: Measurement of PD signal can be substantially affected by deteriorated quality of the transducer, whereas the differences are relatively modest between machines with similar specifications and also between PRF settings within a low range.

Positive synovial vascularity in patients with low disease activity indicates smouldering inflammation leading to joint damage in rheumatoid arthritis: time-integrated joint inflammation estimated by synovial vascularity in each finger joint.

OBJECTIVE: To investigate the relationship between synovial vascularity and joint damage progression in each finger joint of patients with RA under low disease activity during treatment with biologic agents. METHODS: We studied 310 MCP and 310 PIP joints of 31 patients with active RA who were administered adalimumab (ADA) or tocilizumab (TCZ). Patients were examined with clinical and laboratory assessments. Power Doppler sonography was performed at baseline and at weeks 8, 20 and 40. Synovial vascularity was evaluated according to quantitative measurement. Hand and foot radiography was performed at baseline and at week 50. RESULTS: Composite scores of the DAS with 28 joints and the Simplified Disease Activity Index (SDAI) were significantly decreased from baseline to week 8, being sustained at a low level by biologic agents during the observational period. MCP and PIP joints with positive synovial vascularity after week 8 showed more subsequent joint damage progression than joints without synovial vascularity throughout the follow-up. The changes in radiographic progression in these joints were independent of the sum of synovial vascularity from baseline to week 40 or the occasional occurrence of positive synovial vascularity. CONCLUSION: Smouldering inflammation reflected by positive synovial vascularity under low disease activity was linked to joint damage. The damage progressed irrespective of the severity of positive synovial vascularity. Even with a favourable overall therapeutic response, monitoring of synovial vascularity has the potential to provide useful joint information to tailor treatment strategies. Trial registration. University Hospital Medical Information Network Clinical Trials Registry; http://www.umin.ac.jp/ctr/; UMIN000004476.

Semi-quantitative analysis of rheumatoid finger joint synovitis using power Doppler ultrasonography: when to perform follow-up study after treatment consisting mainly of antitumor necrosis factor alpha agent.

PURPOSE: To determine the timing for follow-up study of power Doppler ultrasonography (PDUS) by evaluating the response of finger joint synovitis in patients with rheumatoid arthritis (RA) to treatment including infliximab, an antitumor necrosis factor alpha agent. METHODS AND MATERIALS: Bilateral second/third metacarpo-phalangeal (MCP) joints and second proximal inter-phalangeal (PIP) joints (total of six joints) in 21 patients (18 women and three men; median age 53 years) with chronic active RA were assessed by PDUS before and after 2 weeks, 6 weeks, 14 weeks, 30 weeks, 38 weeks, 46 weeks, and 54 weeks of infliximab infusion. Pulse Doppler settings were standardized for each patient and optimized for the detection of synovial blood flow by adjustment of color gain, pulse repetition, and flow optimization. Power Doppler signal was graded for each joint [joint grade for power Doppler (JGPD) signals], and the sum of the grades of six joints was defined as the PDUS index [joint index for power Doppler signals (JIPD)] at each visit. PDUS and clinical parameters [28-joint disease activity score (DAS28), health assessment questionnaire, and C-reactive protein (CRP) level] were independently assessed and compared with baseline values. The American College of Rheumatology (ACR) core set responders and non-responders at week 54 were compared for clinical parameters and PDUS index at each visit. RESULTS: Fourteen patients completed the planned treatment for 1 year, while six patients dropped out for various reasons and one died suddenly. PDUS was performed a total of 146 times on 467 joints. DAS28 was assessed 127 times. Both DAS28 and JIPD had decreased at the follow-up. Comparative analysis between DAS28 and PDUS was available 125 times. The transverse correlation between the PDUS index and DAS28 was not significant throughout the follow-up period. When responders and non-responders were discriminated at week 54, a logistic regression model for the binary endpoint of responder vs non-responder, with PDUS index as explanatory variable at time point 0, and follow-up revealed statistical significance from week 38 and on. CONCLUSION: PDUS reflected infliximab's effect on pannus vascular signals; this effect was observed as early as 2 weeks after treatment had begun. Also, the responders to treatment at 54 weeks tended to have fewer JIPD than non-responders in the follow-up period. PDUS may be performed at week 38 or later to foresee the response to the treatment at week 54.

Convolutional neural network for classification of two-dimensional array images generated from clinical information may support diagnosis of rheumatoid arthritis.

This research aimed to study the application of deep learning to the diagnosis of rheumatoid arthritis (RA). Definite criteria or direct markers for diagnosing RA are lacking. Rheumatologists diagnose RA according to an integrated assessment based on scientific evidence and clinical experience. Our novel idea was to convert various clinical information from patients into simple two-dimensional images and then use them to fine-tune a convolutional neural network (CNN) to classify RA or nonRA. We semi-quantitatively converted each type of clinical information to four coloured square images and arranged them as one image for each patient. One rheumatologist modified each patient's clinical information to increase learning data. In total, 1037 images (252 RA, 785 nonRA) were used to fine-tune a pretrained CNN with transfer learning. For clinical data (10 RA, 40 nonRA), which were independent of the learning data and were used as testing data, we compared the classification ability of the fine-tuned CNN with that of three expert rheumatologists. Our simple system could potentially support RA diagnosis and therefore might be useful for screening RA in both specialised hospitals and general clinics. This study paves the way to enabling deep learning in the diagnosis of RA.

Active synovitis in the presence of osteitis predicts residual synovitis in patients with rheumatoid arthritis with a clinical response to treatment.

AIM: To clarify the relationship between active synovitis/osteitis and subsequent residual synovitis (R-synovitis) in patients with rheumatoid arthritis (RA). METHODS: Three hundred and twenty finger joints of 16 patients with active RA at baseline (Disease Activity Score with 28 joints - erythrocyte sedimentation rate > 3.2) who subsequently achieved clinical low disease activity or remission afterwards were analyzed. Synovial vascularity (SV) was assessed according to a semi-quantitative ultrasound score (grades 0-3). Active synovitis was defined by SV positivity at baseline. R-synovitis was defined by the presence of grade > 2 SV at the 24th week. Osteitis was detected by magnetic resonance imaging (MRI) at baseline as trabecular bone lesions with water content and indistinct margins. RESULTS: Ultrasonography detected active synovitis in 116 joints at baseline. Forty-seven joints had R-synovitis at the 24th week. MRI detected osteitis in 12 joints at baseline. The presence of active synovitis with osteitis at baseline was significantly correlated with R-synovitis at the 24th week. CONCLUSIONS: Active synovitis in the presence of osteitis predicted R-synovitis regardless of whether there was a clinical improvement in RA.

Ultrasound assessment of synovial pathologic features in rheumatoid arthritis using comprehensive multiplane images of the second metacarpophalangeal joint: identification of the components that are reliable and influential on the global assessment of the whole joint.

OBJECTIVE: The aim of this pilot study was to provide groundwork that could be utilized to optimize the global ultrasound (US) assessment of the whole joint for synovial pathologic features in patients with rheumatoid arthritis (RA). METHODS: US images of the second metacarpophalangeal joint in 8 predefined imaging planes, comprising regions that comprehensively capture the synovial pathologic features of the whole joint, were obtained from 30 patients with RA. Twelve experienced sonographers evaluated these images at the level of both the individual image and the whole joint, using a visual analog scale (VAS) to assess pathologic severity. Interrater reproducibility of the VAS scores was evaluated with intraclass correlation coefficients (ICCs), and factors that independently influenced the global assessment of the whole joint were identified using multiple linear regression analysis. RESULTS: A total of 14,276 VAS scores were analyzed. Interrater reproducibility of any eligible VAS assessment of synovial pathologic features was good (ICC 0.65). US assessment of synovial pathologic features in joints with mild inflammation was less reproducible than that in joints with severe inflammation. Although the most severely affected region in a joint did not always represent the average pathologic severity among the 8 regions, global assessment of the whole joint strongly correlated with assessment of the most severely affected region (P < 0.001). Importantly, the standard, midline imaging plane was not the most influential plane on the global assessment of the whole joint. Assessment of synovial fluid accumulation was not reproducible (ICCs 0.20-0.42) and did not substantially influence the global assessment of synovial inflammation (ß = 0.06). CONCLUSION: The results of this study provide a unique data set that could be utilized to optimize the global US assessment of synovial pathologic features of the whole joint in patients with RA.

Radiographic prognosis of finger joint damage predicted by early alteration in synovial vascularity in patients with rheumatoid arthritis: Potential utility of power doppler sonography in clinical practice.

OBJECTIVE: To investigate the relationship between synovial vascularity and progression of structural bone damage in each finger joint in patients with rheumatoid arthritis (RA) and to demonstrate synovial vascularity as a potential therapeutic marker. METHODS: We studied 250 metacarpophalangeal (MCP) and 250 proximal interphalangeal (PIP) joints of 25 patients with active RA who were administered adalimumab or tocilizumab. Patients were examined with clinical and laboratory assessments. Power Doppler sonography was performed at baseline and at the fourth and eighth weeks. Synovial vascularity was evaluated according to quantitative measurement. Hand and foot radiography was performed at baseline and the twentieth week. RESULTS: Clinical indices such as the 28-joint Disease Activity Score, the Clinical Disease Activity Index, and the Simplified Disease Activity Index were significantly decreased by biologic agents. The MCP and PIP joints with no response in synovial vascularity between baseline and the eighth week (vascularity improvement of ≤70% at the eighth week) showed a higher risk of radiographic progression compared with responsive joints (vascularity improvement of >70% at the eighth week; relative risk 2.33-9). Radiographic progression at the twentieth week was significantly lower in responsive joints than in nonresponsive joints. CONCLUSION: The improvement of synovial vascularity following treatment with biologic agents led to suppression of radiographic progression of RA in each finger joint. The alteration in synovial vascularity numerically reflected therapeutic efficacy. Using vascularity as a marker to determine the most suitable therapeutic approach would be beneficial for patients with active RA.

Change of synovial vascularity in a single finger joint assessed by power doppler sonography correlated with radiographic change in rheumatoid arthritis: comparative study of a novel quantitative score with a semiquantitative score.

OBJECTIVE: To investigate the relationship between synovial vascularity assessed by quantitative power Doppler sonography (PDS) and progression of structural bone damage in a single finger joint in patients with rheumatoid arthritis (RA). METHODS: We studied 190 metacarpophalangeal (MCP) joints and 190 proximal interphalangeal (PIP) joints of 19 patients with active RA who had initial treatment with disease-modifying antirheumatic drugs (DMARDs). Patients were examined by clinical and laboratory assessments throughout the study. Hand and foot radiography was performed at baseline and the twentieth week. Magnetic resonance imaging (MRI) was performed at baseline. PDS was performed at baseline and the eighth week. Synovial vascularity was evaluated according to both quantitative and semiquantitative methods. RESULTS: Quantitative PDS was significantly correlated with the enhancement rate of MRI in each single finger joint. Comparing quantitative synovial vascularity and radiographic change in single MCP or PIP joints, the level of vascularity at baseline showed a significant positive correlation with radiographic progression at the twentieth week. The change of vascularity in response to DMARDs, defined as the percentage change in vascularity by the eighth week from baseline, was inversely correlated with radiographic progression in each MCP joint. The quantitative PDS method was more useful than the semiquantitative method for the evaluation of synovial vascularity in a single finger joint. CONCLUSION: The change of synovial vascularity in a single finger joint determined by quantitative PDS could numerically predict its radiographic progression. Using vascularity as a guide to consider a therapeutic approach would have benefits for patients with active RA.

Power Doppler ultrasound of rheumatoid synovitis: quantification of vascular signal and analysis of interobserver variability.

OBJECTIVE: The objective of this study was to assess interobserver uncertainties in power Doppler (PD) examination of the fingers of patients with rheumatoid arthritis (RA), by separating the source of the discrepancy into (1) acquisition of the images and (2) criteria for assessment of the images. MATERIALS AND METHODS: Twenty patients who had been diagnosed with RA were enrolled in this study. Ultrasound examinations were performed by one inexperienced and two experienced sonographers. Interobserver variation was measured using a conventional semiquantitative image grading scale. Interobserver variation of the quantitative PD (QPD) index (the summation of the colored pixels in a region of interest) was also assessed. RESULTS: The agreement was higher between the two experienced sonographers (kappa value of 0.8) than between experienced and inexperienced sonographers (kappa value, 0.6-0.7) in the semiquantitative image grading scale. Results suggest that the difference in the assessment on the image grading scale was due more to the difference in the acquisition of the images than to variations in the grading criteria between sonographers. An excellent relationship was noted between the image grading scale and the QPD index for Doppler signal with a Spearman's coefficient of rank correlation of 0.83 (P < 0.0001). CONCLUSIONS: Interobserver discrepancies in the image grading and QPD index methods were due more to the difference in the acquisition of the image than to the grading criteria used. The QPD index seems to be as reliable as the image grading scale with reasonable interobserver agreement between experienced sonographers.