H.-E. Langer

Fluorescence Optical Imaging of Juvenile Arthritis

In juvenile idiopathic arthritis (JIA), valid detection of involved joints is essential for correct classification, therapeutic decisions, and prognosis1. Clinical assessment is a particular challenge, and reliable results depend on the ages of the children and their ability to cooperate. Ultrasonography (US) and magnetic resonance imaging are used for imaging in JIA, but have practical limitations. Fluorescence optical imaging (FOI) enables visualization of inflammation in arthritis …

Fluorescence optical imaging and musculoskeletal ultrasonography in juvenile idiopathic polyarticular disease before and during antirheumatic treatment - a multicenter non-interventional diagnostic evaluation

BackgroundValid detection of inflamed joints is essential for correct classification, therapeutic decisions, prognosis and assessment of treatment efficacy in juvenile idiopathic arthritis (JIA). Fluorescence optical imaging (FOI) enables visualization of inflammation in arthritis of finger and hand joints and might be used for monitoring.MethodsA 24-week observational study in polyarticular JIA patients newly starting treatment with methotrexate or an approved biologic was performed in three centers. Patients were evaluated clinically, by gray-scale ultrasonography (GSUS), power-Doppler ultrasonography (PDUS) and FOI at baseline, week 12 and week 24.ResultsOf 37 patients enrolled, 24 patients started methotrexate and 13 patients a biologic for the first time (etanercept n = 11, adalimumab and tocilizumab n = 1 each). Mean JADAS 10 decreased significantly from 17.7 at baseline to 12.2 and 7.2 at week 12 and 24 respectively. PedACR 30/50/70/100 response rates at week 24 were 85%/73%/50%/27%. The total number of clinically active joints in hand and fingers at baseline/week 12/week 24 was 262 (23.6%)/162 (16.4%)/162 (9.0%). By GSUS, at baseline/week 12/week 24, 192 (19.4%)/135 (16.1%)/83 (11.5%) joints showed effusions and 186 (18.8%)/107 (12.7%)/69 (9.6%) showed synovial thickening, and by PDUS 68 (6.9%)/15 (1.8%)/36 (5%) joints showed hyperperfusion. Any sign of arthritis was detected by US in a total of 243 joints (24.5%) at baseline, 161 joints (19.2%) at week 12 and 123 joints (17%) at week 24. By FOI at baseline/week 12/week 24, 430 (38.7%)/280 (29.2%)/215 (27.6%) showed a signal enhancement in at least one phase.Summarizing all three points of time, the highest numbers of signals were detected by FOI with 32% of joints, especially in phase 2, while by US 20.7% and by clinical examination 17.5% of joints were active. A high number of joints (21.1%) had FOI signals but were inactive by clinical examination. A total 20.1% of joints with signals in FOI did not show effusion, synovial thickening or hyperperfusion by US.Because of the high number of negative results, specificity of FOI compared with clinical examination/US/PD was high (84–95%), and sensitivity was only moderate.ConclusionFOI and US could detect clinical but also subclinical inflammation. FOI detected subclinical inflammation to a higher extent than US. Improvement upon treatment with either methotrexate or a biologic can be visualized by FOI and US.Trial registrationDeutsches Register Klinischer Studien DRKS00011579. Registered 10 January 2017.

Sequential high-content profiling of the IgG-autoantibody repertoire reveals novel antigens in rheumatoid arthritis

BackgroundThe aim was to identify novel diagnostic autoantibody candidates for rheumatoid arthritis (RA) by comprehensive screening for autoreactivity.MethodWe incubated 5892 recombinant proteins coupled to fluorescent beads, with patients’ sera for the detection of IgG-autoantibodies in three independent patient cohorts: A (n = 72 patients with established RA); B/B- (n = 116 patients with early RA (B) and n = 51 CCP-negative patients with early RA from B (B-)); and C (n = 184 patients with early seronegative RA), in comparison to matched healthy controls. Intersects of significantly increased autoantibodies as determined by the Mann-Whitney test were sought.ResultScreening of 5892 antigens in RA cohorts A and B, or the seronegative cohorts B- and C revealed intersects of 23 and 13 significantly increased autoantibodies, respectively. Reactivity to three antigens was increased in all cohorts tested: N-acetylglucosamine-1-phosphate transferase, gamma subunit (GNPTG), heterogeneous nuclear ribonucleoprotein A1-like 2 (HNRNPA1), and insulin-like growth factor binding protein 2 (IGFBP2).ConclusionsComprehensive sequential screening for autoantibodies reveals novel candidates for diagnostic markers in both seropositive and seronegative RA and suggests new fields of research into the pathogenesis of RA.

SAT0416 Interreader-reliability of standardized evaluation of ICG-enhanced fluorescence-optical imaging

Background Interpretation of medical images needs to be standardized and trained. This applies also to fluorescence-optical imaging (FOI), a novel tool for assessment of inflammation in patients with arthritis (1). In this study we refined and evaluated the inter-reader reliability of the previously described algorithm of image interpretation of FOI. Objectives To determine the inter-reader reliability of the fluorescence optical imaging activity score (FOIAS) 7 readers from 4 centres each evaluated 34 randomly selected cases (5 RA, 5 PsA, 5 remissions, and 19 EA). FOIAS was analyzed in PrimaVistaMode (PVM) and 3 phases (P1, P2, P3). All participants were blinded for diagnosis and clinical findings. Overall, 28560 data sets were evaluated. Methods All participants were initially trained in software use and basic image interpretation by the supplier of the system. 5 of the 7 readers had no knowledge in the standardized image evaluation. Before starting the study a 2.5h training session was carried out and repeated once. All participants obtained a guideline and picture samples. For image interpretation, the automatically generated gain had to be checked by the readers and corrected as appropriate. The readers had to determine the 3 phases, and evaluate all 4 datasets of each case according to the guideline. Spearman correlations, agreement rates (2) and Cohen’s kappa coefficients were calculated. Results Correlations and agreement rates are presented in table 1. Two readers (2,4) showed relevant difference to the other readers. Cohen’s Kappa was between moderate and substantial. Highest Kappa was found for PVM (κ=0.68). FOIAS Spearman correlations, Spearman correlations Agreement rates, Agreement rates All readers without 2 and 4 All readers without 2 and 4 PVM 0.5 ≤r≤0.9 0.7 ≤r≤0.9 69%≤AR≤91% 82%≤AR≤91% P1 0.4 ≤r≤0.8 0.5 ≤r≤0.8 85%≤AR≤94% 88%≤AR≤94% P2 0.5 ≤r≤0.9 0.6 ≤r≤0.9 53%≤AR≤83% 72%≤AR≤83% P3 0.5 ≤r≤0.8 0.5 ≤r≤0.8 79%≤AR≤95% 87%≤AR≤93% Conclusions There was overall a good to nearly perfect correlation between readers. Thus standardized FOI evaluation gives high agreement in assessment of disease activity using FOIAS. There was high agreement for the decision if a joint is affected or not. Cohens Kappa showed that the standardized protocol is reliable after training. Highest Kappa was found for PVM. This is explicable with the fact, that PVM is a static image, while the image stack is dynamic. Reader 2 and 4 had problems in image interpretation depending on a dyschromatopsia and wrong image adjusting. Further training will be helpful. In conclusion, the used standardized protocol for assessment of inflammatory activity in FOI seems to be reliable and useful in daily practice. Redetermination of interreader-reliability after further refining of the protocol and training is planned. References Werner SG, Langer HE, Ohrndorf et al. Inflammation assessment in patients with arthritis using novel in vivo fluorescence optical imaging technology. Ann Rheum Dis 2011, Epub ahead of print. Schwenke C and Busse R. Analysis of differences in proportions from clustered data with multiple measurements in diagnostic studies. Meth Inform Med 2007 (46), 548-552 Disclosure of Interest S. Werner Grant/Research support from: Pfizer, U. Käßer: None Declared, C. Amberger: None Declared, M. Piesga: None Declared, F. Spiecker: None Declared, C. Volberg: None Declared, C. Schwenke: None Declared, H.-E. Langer Grant/Research support from: Pfizer, M. Backhaus Grant/Research support from: Pfizer

SAT0392 ICG-enhanced fluorescence optical imaging in clinical remission: Longitudinal data in RA and PSA patients with pre/post comparisons

Background ICG (Indocyanine-Green) fluorescence optical imaging (FOI) is a novel imaging technology in rheumatology (1) and may be a suitable tool for monitoring of disease activity and treatment response (2). Objectives This is the first study with longitudinal data of FOI in RA and PsA patients in clinical remission. The objective was to compare clinical activity and FOI findings before, at and after achievement of clinical remission. Methods A total of 113 subjects were included in a prospective study of FOI in RA and PsA patients with low disease activity (inception cohort: disease activity ≤1 at global assessment by patient or physician, NRS 0-10). All patients received a clinical examination by an independent investigator, and blood samples were taken for measurement of systemic inflammation (ESR, CRP). Inflammatory activity in FOI was assessed by an experienced reader using the semiquantitative fluorescence optical imaging activity score (FOIAS) (1), which comprises of the measurement of joint-related fluorescence signals in an automatically generated composite image (Prima Vista Mode, PVM) and in three predefined phases of FOI (P1, P2, P3).In 38 subjects with DAS28 remission (DAS28 <2,6) at least one FOI study had been performed either prior to remission (≥3 months, n=34) or at follow-up (≥3 months, n=31). 11 subjects had sequential FOI examinations prior to and after remission. The sample with a total of 103 FOI studies was selected for further analysis. Results In most patients clinical and FOI activity were following a uniform trend (table). Cross-sectional analysis revealed a moderate correlation of (r=0.4) of DAS28 and FOIAS. FOI evidence of subclinical disease activity was more pronounced in the various phases of a FOI sequence than in PVM. 11 subjects had treatment changes (reduction of DMARDs, tapering of steroid dose) due to clinical remission. In individual patients FOIAS increased with ongoing clinical remission. In joint-to-joint comparisons, those patients showed at first decreasing FOI activity in originally symptomatic joints with the achievement of remission. When treatment was reduced at this stage, then even clinically still asymptomatic patients demonstrated an increase in FOI activity in those same joints. DAS28 TJC SJC FOIASPVM FOIASP1 FOIAS P2 FOIAS P3 FOAIS P1-3 Prior to remission (n=34) 3,87 5 3 11 9 23 7 38 At remission (n=38) 1,7 1 0 5 3 11 2 16 Follow-up (n=31) 1,98 1 0 5 1 7 1 10 Conclusions FOI is a useful tool for monitoring disease activity and treatment response in RA and PsA patients. Most subjects with clinical remission showed residual activity in FOI. Pre/post-comparisons in individual patients suggest that subclinical disease activity in FOI may announce an initiating relapse in patients with premature withdrawal of treatment. References Werner SG, Langer HE, Ohrndorf et al. Inflammation assessment in patients with arthritis using novel in vivo fluorescence optical imaging technology. Ann Rheum Dis Oct 2011, Epub ahead of print. Werner S et al. 2011 ACR/ARHP Annual Scientific Meeting, Chicago, IL, Nov. 4 -9, 2011, Poster 199 Disclosure of Interest S. Werner Grant/Research support from: Pfizer, F. Spiecker: None Declared, C. Hermsen: None Declared, M. Bahner Shareholder of: mivenion GmbH, M. Backhaus Grant/Research support from: Pfizer, H.-E. Langer Grant/Research support from: Pfizer

SAT0526 ICG-Enhanced Fluorescence Optical Imaging (FOI) Detects Typical Inflammatory Changes in Subjects with Arthralgia and Psoriasis

Background Early diagnosis of psoriatic arthritis (PsA) is a major challenge. ICG-enhanced fluorescence optical imaging (FOI) is a novel technology that enables detection of inflammation in the hands with high sensitivity and specificity comparable to MRI arthrosonography (1). Objectives To report for the first time of FOI in subjects with arthralgia and psoriasis or family history of psoriasis but without signs of clinically established arthritis. Methods 19 subjects (12 female, 7 male; mean age 43 years, range 15-88) were referred to the early arthritis clinic with cutaneous manifestations of psoriasis or family history of psoriasis and pain in various joints (monarticular, oligoarticular, polyarticular). None had a history of actual or previous arthritis or tendinitis or any signs of active synovitis at clinical examination. FOI was performed following the usual procedure (1). The findings were compared to FOI in 8 patients (7 female, 1 male, mean 53 years, range 29-70 years) with very early PsA (mean disease duration of 8 weeks, range 1-12 weeks). Results FOI displayed inflammatory changes in all subjects. Joint-related signal intensities were seen in 19/19 (100%), and extraarticular increases signal intensities in 17/19 sequences (89%). The morphology of FOI inflammation (figure 1 right) was indistinguishable from the findings that were seen in patients with very early PsA (figure 1 left) and showed a marked difference compared to FOI in healthy subjects. 5/19 individuals (26%) without clinical symptoms in the hands had positive FOI changes in all small joint regions (wrist, MCP, PIP, DIP). 17/19 FOI findings (89%) showed a triangular, slightly accurate enhancement in projection of the synovio-entheseal complex (2) that may be pathognomonic for PsA (1). Image/graph Conclusions The detection of typical inflammatory changes in subjects with cutaneous manifestations of psoriasis or family history of psoriasis and joint pain but without clinical signs of synovitis or tendinitis suggests that a non-arthritic, subclinical disease stage may precede the onset of clinically active PsA. With the visualization of inflammation in those subjects FOI possibly is a new diagnostic opportunity in incipient PsA. Further investigations with follow up examinations to proof this concept are necessary. References Werner SG, Langer HE*, Ohrndorf S*, Bahner M, Schott P, Schwenke C, Schirner M, Bastian H, Lind-Albrecht G, Kurtz B, Burmester GR, Backhaus M.*equal contribution: Inflammation assessment in patients with arthritis using a novel in vivo fluorescence optical imaging technology. Ann Rheum Dis. 2012 Apr;71(4):504-10 McGonagle D, Lories RJ, Tan AL, et al. The concept of a “synovio-entheseal complex” and its implications for understanding joint inflammation and damage in psoriatic arthritis and beyond. Arthritis Rheum 2007;56:2482–91. Disclosure of Interest None Declared

OP0051 The Extraarticular Patterns of Icg-Enhanced Fluorescence Optical Imaging in Psoriatic Arthritis

Background ICG-enhanced fluorescence optical imaging (FOI) is a novel technology for the assessment of inflammation in arthritis [1,2]. Previous studies were mainly focused on articular findings. Extraarticular changes have not yet been studied systematically. Objectives This is the first report of extraarticular FOI patterns in a large cohort of subjects with psoriatic arthritis (PsA). Methods 201 FOI sequences in 172 patients with PsA (59% females, mean age 54,1 years, mean disease duration 5,8 years (median 3,1 years, range 2 weeks – 42,7 years), mean DAS28 3,0) were selected from our FOI registry. FOI was performed according to the standard procedure [1,2]. 36 regions (both hands: nail, nail fold, middle phalanx of D 2-5, proximal phalanx of D 1-5, metacarpal area) were read for the sum image (PVM) and the phases P1 and P2 [1]. Different FOI patterns were identified, characterized and classified by the method of categorical morphological analysis. 30 subjects with seropositive, anti-CCP-positive rheumatoid arthritis (mean disease duration 4,6 years, median 1,9 years, mean DAS28 3,5) served as control. Results 16 distinct extraarticular FOI patterns could be identified in subjects with PsA in the following areas. (A) Nail: Cold Nail, Green Nail, Hot Nail, Caldera, Half Moon. (B) Nail fold: Werners sign [1], Bishops crook

AB0754 Icg-enhanced fluorescence optical imaging detects typical inflammatory changes in asymptomatic subjects with elevated rheumatoid factor or anti-ccp antibodies

Background In patients with rheumatoid arthritis (RA) anti-CCP antibodies have been found many years before clinical presentation of active disease (1,2). Elevated rheumatoid factor (RF) in healthy subjects increases the long term risk of RA up to 26-fold and the 10 year absolute risk of RA up to 32% (3). ICG enhanced fluorescence optical imaging (FOI) is a new technology offering sensitive imaging detection of inflammatory changes in subjects with arthritis (4). Objectives To report for the first time of typical inflammatory FOI findings in asymptomatic subjects with elevated RA-typical autoantibodies. Methods Three asymptomatic male individuals (53, 66 and 76 years of age) with elevated IgM-RF (turbidimetric method) (28 IU/ml, 77 IU/ml (ELISA 422 U/ml), 174 IU/ml) and / or anti-CCP antibodies (ratio 0.36, 0.48, 3.79; normal < 1.0) in general practice have been referred to the early arthritis clinic for differential diagnosis. None of the subjects had a history of actual or previous inflammatory joint disease, notably no tender or swollen joints or morning stiffness. Clinical examination was unremarkable; particularly no signs of inflammation were present. CRP was normal (0.1 mg/dl, 0.1 mg/dl, 0.0 mg/dl), ESR was elevated in one subject (8 mm/h, 30 mm/h, 5 mm/h). After informed consent FOI was performed following the usual procedure (4). Results FOI displayed distinct inflammatory changes in the small joints of the hands (wrist, MCP, PIP) in all subjects. The pathological signal intensities were comparable to findings in active rheumatoid arthritis but showed a marked difference compared to FOI in healthy subjects or in RA patients in clinical remission. Follow-up examinations after 3 months demonstrated an increasing FOI activity in one untreated subject while pathological FOI findings, ESR and RF titer decreased in a second patient with hydroxychloroquine therapy (ESR: 30 -> 14 mm/h; RF: 422 -> 341 U/ml), after 3 and 9 months. Conclusions These findings may indicate that a stage of subclinical inflammation precedes the clinical onset of active arthritis in the development of RA. With the visualization of typical inflammatory changes in asymptomatic subjects with elevated RF or positive anti-CCP antibodies FOI possibly opens new diagnostic opportunities in preclinical RA. Further investigations with follow up examinations to proof this concept are necessary. References Rantapää-Dahlqvist S, de Jong BA, Berglin E, et al.: Antibodies against cyclic citrullinated peptide and IgA rheumatoid factor predict the development of rheumatoid arthritis. Arthritis Rheum. 2003 Oct;48(10):2741-9. Nielen MM, van Schaardenburg D, Reesink HW, et al: Specific autoantibodies precede the symptoms of rheumatoid arthritis: a study of serial measurements in blood donors. Arthritis Rheum. 2004 Feb;50(2):380-6. Nielsen SF, Bojesen SE, Schnohr P, Nordestgaard BG.: Elevated rheumatoid factor and long term risk of rheumatoid arthritis: a prospective cohort study. BMJ. 2012 Sep 6;345:e5244. Werner SG, Langer HE*, Ohrndorf S*, et al.*equal contribution: Inflammation assessment in patients with arthritis using a novel in vivo fluorescence optical imaging technology. Ann Rheum Dis. 2012 Apr;71(4):504-10 Disclosure of Interest None Declared

AB0733 Treatment monitoring of fluorescence optical imaging (foi) using automated, computer-based quantitative assessment

Background Fluorescence optical imaging (FOI) with the Xiralite® system is clinically available for diagnostic imaging of inflammation and has been shown to be a suitable tool to assess treatment response in subjects with RA and PsA. Changes in FOI are measured using the semi-quantitative fluorescence optical imaging activity score (FOIAS) which allows for a low inter-reader variability1. Most recently, an automatic, computer-based image analysis of FOI (DACT) has been described and validated in healthy subjects2. Objectives To evaluate an automatic computer-based analysis of FOI in patients with RA or PsA under treatment. Methods 30 patients with rheumatoid (RA) or psoriatic (PsA) arthritis were examined before starting treatment (visit 1) and at follow-up (visit 2). Treatment response was assessed using DAS28, cFOIAS and the automated calculated DACT. First, 3 readers analyzed all 60 image data sets individually. For articular location of increased signal intensities (ISI) the FOIAS was used. For extraarticular location the signals were graded semiquantitatively on a scale of 0 to 2. These values were added to a single number representing the overall fluorescence signal intensity of the hands (cFOIAS). For DACT composite images were generated automatically. Using dedicated parameters of the histograms, automatic extraction of the hands from the image background was performed by the computer. The algorithm separated the hands from the forearm in a standardized manner by using a multiple of the length of the middle finger. A threshold in the fluorescence intensity curve was set to discriminate high and low intensity areas. The area of high intensity was calculated and the values of each patient were divided by the 95th percentile of normal individuals which was defined as reference value. DACT was expressed as high signal intensity area patient / healthy reference. DACT in healthy individuals equals 1. Then cFOIAS and DACT values were compared. Results 60 left and 60 right hands were correctly extracted from the auto-scaled composite image of the first 240 seconds. The intra-individual variation of the extraction procedure measured as intensity area of the hand in the consecutive procedures was 1.1 % + 1.0 (range: 0.04 – 4.9). cFOIAS scores strongly correlate with automated calculated DACT (0.86 / reader 1, 0.84 / reader 2 and 0.85 / reader 3). Agreement of declining DAS28 with declining cFOIAS was found in 16/30 (reader 1), 17/30 (reader 2) and 15/30 (reader 3) treatment courses. Agreement of declining DAS28 with declining DACT was found in 16/30 treatment course. Conclusions This first clinical trial in patients with RA or PsA under treatment with follow-up FOI exams demonstrates that automatic, computer-based image analysis of FOI to calculate DACT values is technically feasible, offers high reproducibility and high agreement with cFOIAS score reading, while agreement of DACT value with DAS28 was only moderate. Even very low changes of the DACT value can be measured and considered as statistically significant. References Werner SG et al. Indocyanine Green Enhanced Optical Imaging Using for Monitoring of Treatment Response. Arthritis & Rheumatism 2011: 63 (10); S73 Schirner M. et al. Methods for automated, computer-based quantitative assessment of fluorescence optical imaging. Ann Rheum Dis 2012;71(Suppl3):711 Disclosure of Interest M. Bahner Shareholder of: mivenion GmbH, Employee of: mivenion GmbH, S. Werner: None Declared, M. Cziumplik Employee of: mivenion GmbH, J. Berger Employee of: mivenion GmbH, H.-E. Langer: None Declared, M. Schirner Shareholder of: mivenion GmbH, Employee of: mivenion GmbH

THU0422 ICG-enhanced fluorescence optical imaging reveals subclinical disease activity in rheumatoid and psoriatic arthritis patients who have achieved clinical remission:

Background Both MRI and ultrasonography (US) detect subclinical disease activity in most remission and low disease activity patients with rheumatoid arthritis (RA) (1, 2). Fluorescence optical imaging (FOI) has been shown to be not only a sensitive detector of synovitis (3), but also a useful tool in assessing treatment response in patients with RA and psoriatic arthritis (PsA) (4). Objectives This is the first data on FOI in RA and PsA patients in clinical remission. The objective was to evaluate FOI as a method to detect subclinical disease activity in these patients. Methods Admission criteria of this prospective study was patient or physician global assessment of disease activity of 10% or less on a visual analogue scale (VAS 0-10), thus resulting in the inclusion of 113 consecutive patients into the inception cohort. Admitted patients received a clinical examination by an independent investigator, and blood samples were taken for measurement of systemic inflammation (ESR, CRP). With these data, patients in DAS28 remission (DAS28 <2.6), SDAI remission (SDAI ≤3.3), CDAI remission (CDAI ≤2.8) and 2011 ACR/EULAR remission (Boolean based definition) were determined. Inflammatory activity in FOI was assessed by an experienced reader using the semiquantitative fluorescent optical imaging activity score (FOIAS) (3), which comprises of the measurement of joint-related fluorescent signal in an automatically generated composite image (Prima Vista Mode, PVM) and in three predefined phases of FOI (P1, P2, P3). Results 78-87% of patients in remission showed remaining inflammatory activity in the PVM (table). DAS28 <2,6 SDAI ≤3,3 CDAI ≤2,8 Boolean Criteria PVM 65/83 (78%) 53/61 (87%) 48/56 (86%) 41/47 (87%) Phase I 17/83 (20%) 15/61 (25%) 14/56 (25%) 13/47 (28%) Phase II 81/83 (98%) 60/61 (98%) 55/56 (98%) 46/47 (98%) Phase III 39/83 (47%) 32/61 (52%) 27/56 (48%) 24/47 (51%) Differences in the occurrence of inflammatory activity between the phases were significant to highly significant, with the lowest incidence of activity in P1 (20-28%). When excluding low signal enhancement and only regarding moderate to strong enhancement (≥2 on the semiquantitative score of 0-3), incidence of inflammatory activity was lower: 43% in PVM, 13% in P1, 78% in P2 and 17% in P3 for the DAS28 remission group. Comparing inflammatory activity in RA and PsA patients in DAS28 remission revealed no significant difference, though a clear trend towards more P1-activity in PsA patients could be observed (18% vs. 29% in RA and PsA patients, respectively). Conclusions Frequency of subclinical disease activity observed in FOI is similar to that stated in MRI and US remission studies. Frequency of P1-activity in FOI is comparable to the reported frequency of power Doppler signal in patients with low disease activity or in remission (1), which is consistent with the previously established high agreement rates between P1 and power Doppler sonography (3). The prognostic value of subclinical FOI activity in remission patients is yet to be determined. References Gandjbakhch F et al. Ann Rheum Dis2011 Dec;70(12):2159-62. Foltz V et al. Arthritis Rheum. 2012 Jan;64(1):67-76. Werner S et al. Ann Rheum Dis 2011;70, Online First, published on Oct. 12, 2011. Werner S et al. 2011 ACR/ARHP Annual Scientific Meeting, Chicago, IL, Nov. 4-9, 2011, Poster 199 Disclosure of Interest F. Spiecker: None Declared, S. Werner Grant/Research support from: Pfizer, C. Hermsen: None Declared, M. Bahner Shareholder of: mivenion GmbH, M. Backhaus Grant/Research support from: Pfizer, H.-E. Langer Grant/Research support from: Pfizer