Prospective multicenter evaluation of adherence to the Dutch guideline for children aged 0-16 years with fever without a source-febrile illness in children (FINCH) study.

Evaluation of guidelines in actual practice is a crucial step in guideline improvement. A retrospective evaluation of the Dutch guideline for children with fever without an apparent source (FWS) showed 50% adherence in young infants. We prospectively evaluated adherence to the Dutch guideline and its impact on management in current practice. Prospective observational multicenter cross-sectional study, including children 3 days to 16 years old presented for FWS at one of seven emergency departments in participating secondary and tertiary care hospitals in the Netherlands. Adherence to the Dutch FWS guideline, adapted from the National Institute for Health and Care Excellence (NICE) guideline, was evaluated, and patterns in non-adherence and the impact of non-adherence on clinical outcomes and resource use were explored. Adherence to the guideline was 192/370 (52%). Adherence was lowest in patients categorized as high risk for severe infection (72/187, 39%), compared to the low-risk group (64/73, 88%). Differences in adherence were significant between risk categories (P < 0.001) but not between age categories. In case of non-adherence, less urinalysis, fewer bacterial cultures (blood, urine, and cerebral spinal fluid), and less empirical antibiotic treatment were performed (P < 0.050). Clinical outcomes were not significantly different between the non-adherence and the adherence group, particularly regarding missed severe infections. CONCLUSIONS: We found a high non-adherence rate of 48%, which did not lead to unfavorable clinical outcomes. This substantiates the need for a critical reevaluation of the FWS guideline and its indications for bacterial cultures, viral testing, and antibiotic treatment. WHAT IS KNOWN: • Despite the development of national guidelines, variation in practice is still substantial in the assessment of febrile children to distinguish severe infection from mild self-limiting disease. • Previous retrospective research suggests low adherence to national guidelines for febrile children in practice. WHAT IS NEW: • In case of non-adherence to the Dutch national guideline, similar to the National Institute for Health and Care Excellence (NICE) guideline from the United Kingdom, physicians have used fewer resources than the guideline recommended without increasing missed severe infections.

Can Presepsin Be Valuable in Reducing Unnecessary Antibiotic Exposure after Birth?

BACKGROUND: Due to a lack of rapid, accurate diagnostic tools for early-onset neonatal sepsis (EOS) at the initial suspicion, infants are often unnecessarily given antibiotics directly after birth. We aimed to determine the diagnostic accuracy of presepsin for EOS before antibiotic initiation and to investigate whether presepsin can be used to guide clinicians' decisions on whether to start antibiotics. METHODS: In this multicenter prospective observational cohort study, all infants who started on antibiotics for EOS suspicion were consecutively included. Presepsin concentrations were determined in blood samples collected at the initial EOS suspicion (t = 0). In addition to this, samples were collected at 3, 6, 12 and 24 h after the initial EOS suspicion and from the umbilical cord directly after birth. The diagnostic accuracy of presepsin was calculated. RESULTS: A total of 333 infants were included, of whom 169 were born preterm. We included 65 term and 15 preterm EOS cases. At the initial EOS suspicion, the area under the curve (AUC) was 0.60 (95% confidence interval (CI) 0.50-0.70) in the term-born infants compared to 0.84 (95% CI 0.73-0.95) in the preterm infants. A cut-off value of 645 pg/mL resulted in a sensitivity of 100% and a specificity of 54% in the preterm infants. The presepsin concentrations in cord blood and at other time points did not differ significantly from the concentrations at the initial EOS suspicion. CONCLUSIONS: Presepsin is a biomarker with an acceptable diagnostic accuracy for EOS (culture-proven and clinical EOS) in preterm infants and might be of value in reducing antibiotic exposure after birth when appended to current EOS guidelines. However, the small number of EOS cases prevents us from drawing firm conclusions. Further research should be performed to evaluate whether appending a presepsin-guided step to current EOS guidelines leads to a safe decrease in antibiotic overtreatment and antibiotic-related morbidity.

Group B Streptococcus Early-Onset Disease: New Preventive and Diagnostic Tools to Decrease the Burden of Antibiotic Use.

The difficulty in recognizing early-onset neonatal sepsis (EONS) in a timely manner due to non-specific symptoms and the limitations of diagnostic tests, combined with the risk of serious consequences if EONS is not treated in a timely manner, has resulted in a low threshold for starting empirical antibiotic treatment. New guideline strategies, such as the neonatal sepsis calculator, have been proven to reduce the antibiotic burden related to EONS, but lack sensitivity for detecting EONS. In this review, the potential of novel, targeted preventive and diagnostic methods for EONS is discussed from three different perspectives: maternal, umbilical cord and newborn perspectives. Promising strategies from the maternal perspective include Group B Streptococcus (GBS) prevention, exploring the virulence factors of GBS, maternal immunization and antepartum biomarkers. The diagnostic methods obtained from the umbilical cord are preliminary but promising. Finally, promising fields from the newborn perspective include biomarkers, new microbiological techniques and clinical prediction and monitoring strategies. Consensus on the definition of EONS and the standardization of research on novel diagnostic biomarkers are crucial for future implementation and to reduce current antibiotic overexposure in newborns.

Considerations for future studies on the effect of late phase oxygen strategies on retinopathy of prematurity.

Strategies to ensure high intraocular oxygen delivery to the developing retina after 32 weeks gestational age, such as higher saturation targets and/or higher hemoglobin levels, are hypothesized to prevent ophthalmological treatment for retinopathy of prematurity (ROP). This short report summarizes the current evidence of these strategies, and discusses possibilities of future studies. A large sample size would be required and therefore the feasibility of a future randomized controlled trial is questioned.

Comparison of contrast-enhanced MRI features of the (teno)synovium in the wrist of patients with juvenile idiopathic arthritis and pediatric controls.

To directly compare and describe the differences between juvenile idiopathic arthritis (JIA) patients and pediatric controls regarding features of the synovial and tenosynovial membrane on contrast-enhanced magnetic resonance imaging (MRI) of the wrist. T1-weighted contrast-enhanced MRI scans of 25 JIA patients with clinically active wrist arthritis and 25 children without a history of joint complaints nor any clinical signs of joint inflammation were evaluated by two readers blinded to clinical data. The synovium was scored at five anatomical sites based on thickening of the synovium (0-3 scale) and synovial enhancement (0-2 scale). Thickening and/or enhancement of the tenosynovium was scored at four anatomical sites using a 0-3 scale. Significantly higher scores for synovial thickening (median 4 vs. 1, p < 0.001) and synovial enhancement (median 4 vs. 1, p < 0.001) are found in the wrist of JIA patients as compared to controls. JIA patients experienced the highest synovial scores at the mid-/inter-carpal, 2nd -5th carpometacarpal, and radiocarpal joints. No significant difference in tenosynovial scores is found between both groups (median 0 vs. 0, p = 0.220). This study highlights the higher synovial thickening/enhancement scores on contrast-enhanced MRI of the wrist in JIA patients compared to pediatric controls. Tenosynovial thickening and/or enhancement was rarely present in both groups. In JIA patients, synovial thickening and enhancement were particularly present at three anatomical sites. These results substantially support rheumatologists and radiologists when navigating through MRI of the wrist in search for JIA disease activity.

Staphylococcal Scalded Skin Syndrome in Neonates: Case Series and Overview of Outbreaks.

Skin and soft tissue infections caused by Staphylococcus aureus (S. aureus) cover a wide spectrum of diseases in neonates, including staphylococcal scalded skin syndrome (SSSS). We describe a representative case of SSSS in neonatal twins, which despite recurrence showed a mild clinical disease course. This case was part of a small outbreak on a neonatal intensive care unit and therefore exemplifies the existence of neonatal outbreaks with skin and soft tissue infections by S. aureus. Diagnosis is generally based on the clinical picture and response to antibiotics, but can be aided by histology and cultures. Sequence-based molecular techniques are available to evaluate typing and virulence of S. aureus in outbreak or surveillance settings. The pillars of treatment are antibiotics and supportive care. Methicillin resistance remains a topic of concern, especially in outbreak settings. Our overview of numerous outbreaks of neonatal S. aureus skin infections underlines the importance of outbreak management strategies, including screening to identify the source of the outbreak, and limiting exposure through hygienic measures and establishment of physical boundaries.

Exploring contrast-enhanced MRI findings of the clinically non-inflamed symptomatic pediatric wrist.

BACKGROUND: Knowledge of the synovial and tenosynovial appearance of the clinically non-arthritic symptomatic juvenile wrist using contrast-enhanced magnetic resonance imaging (MRI) is sparse. OBJECTIVES: To analyze contrast-enhanced MRI findings of the clinically non-inflamed symptomatic pediatric wrist, focusing on the enhancing synovial and tenosynovial membrane. To evaluate the coexistent presence of (teno)synovial enhancement, joint fluid, bony depressions and medullary changes suggestive of bone marrow edema. MATERIALS AND METHODS: We included 20 children (15 girls; age range: 7.5-17.6 years) who underwent contrast-enhanced MRI of the wrist, based on initial clinical indication, and eventually turned out to be unaffected by arthritic or orthopedic disorders. Various imaging characteristics of the synovium, tenosynovium, joint fluid, bone tissue and bone marrow were evaluated using existing MRI scoring systems. RESULTS: In 3/20 (15%) children, mild or moderate-severe synovial enhancement was observed and 2/20 (10%) children showed mild tenosynovial enhancement/thickening. Joint fluid (11/20 children; 55%), bony depressions (20/20 children; 100%) and medullary changes suggestive of bone marrow edema (6/20; 30%) were found in a substantial percentage of children. The most frequently observed combination of coexisting imaging characteristics was bony depressions with ≥2 mm joint fluid, which was found in 7/20 (35%) children. Simultaneous presence of synovial and tenosynovial enhancement/thickening, bony depressions and medullary changes suggestive of bone marrow edema was observed in one child. CONCLUSION: Several juvenile idiopathic arthritis-relevant MRI characteristics can be observed in the clinically non-inflamed symptomatic pediatric wrist.

Juvenile Idiopathic Arthritis: Diffusion-weighted MRI in the Assessment of Arthritis in the Knee.

Background Diffusion-weighted imaging (DWI) can depict the inflamed synovial membrane in arthritis. Purpose To study the diagnostic accuracy of DWI for the detection of arthritis compared with the clinical reference standard and to compare DWI to contrast material-enhanced MRI for the detection of synovial inflammation. Materials and Methods In this institutional review board-approved prospective study, 45 participants with juvenile idiopathic arthritis (JIA) or suspected of having JIA (seven boys, 38 girls; median age, 14 years [interquartile range, 12-16 years]) were included between December 2015 and December 2018. Study participants underwent pre- and postcontrast 3.0-T MRI of the knee with an additional DWI sequence. For the clinical reference standard, a multidisciplinary team determined the presence or absence of arthritis on the basis of clinical, laboratory, and imaging findings (excluding DWI). Two data sets were scored by two radiologists blinded to all clinical data; data set 1 contained pre- and postcontrast sequences (contrast-enhanced MRI), and data set 2 contained precontrast and DWI sequences (DWI). Diagnostic accuracy was determined by comparing the scores of the DWI data set to those of the clinical reference standard. Second, DWI was compared with contrast-enhanced MRI regarding detection of synovial inflammation. Results Sensitivity for detection of arthritis for DWI was 93% (13 of the 14 participants with arthritis were correctly classified with DWI; 95% confidence interval [CI]: 64%, 100%) and specificity was 81% (25 of 31 participants without arthritis were correctly classified with DWI; 95% CI: 62%, 92%). Scores for synovial inflammation at DWI and contrast-enhanced MRI agreed in 37 of 45 participants (82%), resulting in a sensitivity of 92% (12 of 13 participants; 95% CI: 62%, 100%) and specificity of 78% (25 of 32 participants; 95% CI: 60%, 90%) with DWI when contrast-enhanced MRI was considered the reference standard. Conclusion Diffusion-weighted imaging (DWI) was accurate in detecting arthritis in pediatric participants with juvenile idiopathic arthritis (JIA) or suspected of having JIA and showed agreement with contrast-enhanced MRI. The results indicate that DWI could replace contrast-enhanced MRI for imaging of synovial inflammation in this patient group. © RSNA, 2020 Online supplemental material is available for this article.

Consider the wrist: a retrospective study on pediatric connective tissue disease with MRI.

The aim of this study is to describe the clinical characteristics and MRI findings of the wrist in a cohort of children suffering from connective tissue disease with musculoskeletal involvement. Ten patients with pediatric connective tissue disease [median age 14.7 years (IQR 12.7-16.6 years), 70% female] were identified from a large MRI database. Clinical findings during the disease course were retrospectively obtained from patient charts and findings at the time of MRI were prospectively registered in the MRI database. MRI wrist datasets were evaluated by three readers in consensus for synovitis, tenosynovitis, bone marrow changes, bone erosions and myositis. Patients suffered from connective tissue disease with clinical overlap of subtypes systemic lupus erythematosus, Sjögren syndrome and dermatomyositis. Median onset of disease was at 12.3 years (IQR 7.8-14.8 years). Clinical arthritis activity was scored low (median visual analogue scale physician 19, IQR 7-31). Notwithstanding, extensive inflammatory abnormalities such as synovitis and tenosynovitis were found in the wrist of 7/10 patients. Osteochondral involvement was detected in 3/10 patients. In a small cohort of children with connective tissue disease and musculoskeletal symptoms, severe inflammatory abnormalities of the involved wrist were present in the MRI, while clinical disease scores suggested mild disease activity. Therefore, clinicians should consider the wrist as vulnerable for joint damage and can add MRI as a helpful tool in the management of patients with pediatric connective tissue disease and musculoskeletal involvement.

Soluble CD14 subtype (sCD14-ST) as biomarker in neonatal early-onset sepsis and late-onset sepsis: a systematic review and meta-analysis.

BACKGROUND: Early diagnosis of bacterial sepsis in neonates is hampered by non-specific symptoms and the lack of rapid responding laboratory measures. The biomarker soluble CD14 subtype (sCD14-ST) seems promising in the diagnostic process of neonatal sepsis. In order to evaluate the differences in diagnostic accuracy of sCD14-ST between early onset sepsis (EOS) and late onset sepsis (LOS) we assessed this systematic review and meta-analysis. RESULTS: Twelve articles were included in the systematic review and 10 in the meta-analysis. There was a high risk of bias on patient selection, index test and/or flow and timing. The overall quality of the included studies was moderate. At sepsis onset a consequently higher level of sCD14-ST was found in septic neonates compared to healthy controls with significant higher levels in LOS compared to EOS. In the first 24 h after sepsis onset a significant increase in pooled means of plasma sCD14-ST levels was seen in EOS (t(71.6) = 7.3, p < .0001) while this was not seen in LOS or healthy controls. Optimal cut-off values ranged from 305 to 672 ng/l for EOS cases versus healthy controls. The pooled sensitivity was 81% (95%CI: 0.76-0.85), the pooled specificity was 86% (0.81-0.89) with an AUC of 0.9412 (SE 0.1178). In LOS optimal cut-off values ranged from 801 to 885 ng/l with a pooled sensitivity of 81% (0.74-0.86) and a pooled specificity of 100% (0.98-1.00). An AUC and SROC was not estimable in LOS because of the low number of studies. CONCLUSIONS: sCD14-ST is a promising and rapid-responding diagnostic biomarker for EOS and LOS. The difference in pooled means between EOS and LOS underlines the importance to consider EOS and LOS as two different disease entities, requiring separate analysis in original articles and systematic reviews.

Prolonged time between intravenous contrast administration and image acquisition results in increased synovial thickness at magnetic resonance imaging in patients with juvenile idiopathic arthritis.

BACKGROUND: Post-contrast synovial thickness measurement is necessary for scoring disease activity in juvenile idiopathic arthritis (JIA). However, the timing of post-contrast sequences varies widely among institutions. This variation in timing could influence thickness measurements. OBJECTIVE: To measure thickness of the synovial membrane on early and late post-contrast knee magnetic resonance (MR) images of patients with JIA. MATERIALS AND METHODS: Dynamic contrast-enhanced T1-weighted knee MR images of 53 children with JIA with current or past knee arthritis were used to study synovial thickness at time point 1 (about 1 min) and time point 2 (about 5 min after contrast administration). Two experienced readers, who were blinded for the time point, independently measured synovial thickness at a predefined, marked location in the patellofemoral compartment on randomized images. Synovial thickness at the two time points was compared using the Wilcoxon signed rank test. Repeatibility of the synovial thickness measurements was studied using intraclass correlation coefficients and Bland-Altman plots. RESULTS: Median synovial thickness of the 53 patients (median age: 13.5 years, 59% female) increased with prolonged post-contrast interval with a synovial thickness of 1.4 mm at time point 1 and a synovial thickness of 1.5 mm at time point 2 (P<0.001). Repeated synovial thickness measurements showed an intraclass correlation coefficient (ICC) of 0.75, P<0.05 for time point 1 and an ICC of 0.91, P<0.05 for time point 2. CONCLUSION: Post-contrast synovial membrane thickness measurements are time-dependent. Therefore, standardization of post-contrast image acquisition timing is important to achieve consistent grading of synovial inflammation.

Correction to: Diffusion-weighted imaging for assessment of synovial inflammation in juvenile idiopathic arthritis: a promising imaging biomarker as an alternative to gadolinium-based contrast agents.

The original version of this article, published on 12 June 2017, unfortunately contained a mistake.

Current status of wrist imaging in juvenile idiopathic arthritis.

Wrist involvement occurs in about one-quarter of patients diagnosed with juvenile idiopathic arthritis (JIA), increasing to 40% 5 years after diagnosis. The imaging appearances, both for active inflammation and permanent change, differ from those seen in adult rheumatoid arthritis; therefore, a child-specific approach is crucial for correct assessment. In this review article, we provide an update on the current status for imaging wrist JIA, with a focus on evidence-based practice.

Normal MRI findings of the knee in patients with clinically active juvenile idiopathic arthritis.

OBJECTIVE: In a number of patients with clinically active juvenile idiopathic arthritis (JIA), contrast-enhanced MRI shows no signs of synovitis. The objective of this study was to assess the frequency and the patient characteristics in clinically active JIA patients in which MRI showed no signs of synovitis. METHODS: From our cohort of 313 patients in which contrast-enhanced MRI of the knee had been performed, we selected 72 JIA patients with clinically active disease involving the target joint. The validated Juvenile Arthritis MRI Scoring (JAMRIS) system was used to evaluate synovial thickening. Patients were divided into two groups based on MRI outcome: Group 1: thickened synovium on MRI (JAMRIS score ≥1) or Group 2: normal synovium on MRI (JAMRIS score 0). Patient characteristics and disease activity parameters were then compared. RESULTS: In 35% (25/72) of these patients, MRI results contrasted with the clinical assessment (Group 2). In comparison to Group 1, the patients with discrepant findings were significantly older at the date of examination and JIA had been diagnosed at later age (median age of 13.2 vs. 10.9 and median age 10.0 vs. 8.0 respectively). In Group 2 there were significantly more patients with RF-negative polyarticular disease. CONCLUSION: Patients with RF-negative polyarticular JIA who had been diagnosed at a later age and were older at the time of MRI were most likely to be considered clinically active while MRI showed no signs of synovitis. These particular JIA patients may benefit from monitoring of disease activity by MRI to prevent overtreatment.

Imaging in juvenile idiopathic arthritis - international initiatives and ongoing work.

Imaging is increasingly being integrated into clinical practice to improve diagnosis, disease control and outcome in children with juvenile idiopathic arthritis. Over the last decades several international groups have been launched to standardize and validate different imaging techniques. To enhance transparency and facilitate collaboration, we present an overview of ongoing initiatives.

Juvenile idiopathic arthritis: magnetic resonance imaging of the clinically unaffected knee.

BACKGROUND: Synovial thickening detected on magnetic resonance imaging (MRI) is present in a significant number of children with clinically inactive juvenile idiopathic arthritis (JIA). OBJECTIVE: To evaluate patient characteristics and disease activity parameters in a cohort of children with clinically inactive JIA, both with and without synovial thickening, in order to clarify the observed discrepancy between clinical and MRI assessments. MATERIALS AND METHODS: We prospectively enrolled 52 clinically inactive JIA patients (median age 13.3 years, 63.5% girls) who underwent MRI of the knee as major target joint in JIA. Children were divided into two groups based on MRI outcome: group 1, with synovial thickening on MRI; and group 2, with no synovial thickening on MRI. We used the Juvenile Arthritis MRI Scoring system to evaluate synovial thickness. We compared patient characteristics and disease activity parameters between the groups. RESULTS: Synovial thickening on MRI was present in 18 clinically inactive patients (group 1, 34.6%). The age was significantly lower for the patients in group 1 (median 10.7 versus 14.4, P=0.008). No significant differences were observed in any of the other patient characteristics nor the disease activity parameters tested. CONCLUSION: Synovial thickening on MRI was present in nearly 35% of the children with clinically inactive JIA. Children with synovial thickening on MRI were significantly younger than those without. This might indicate that younger patients are at risk of subclinical disease activity and under-treatment, although the exact clinical relevance of synovial thickening on MRI has not been determined.

Contrast-enhanced MRI findings of the knee in healthy children; establishing normal values.

OBJECTIVES: To define normative standards for the knee in healthy children using contrast-enhanced MRI, focusing on normal synovial membrane thickness. Secondly, presence of joint fluid and bone marrow oedema was evaluated. METHODS: For this study, children without disorders potentially resulting in (accompanying) arthritis were included. Patients underwent clinical assessments, followed by contrast-enhanced MRI. MRI features were evaluated in consensus using the Juvenile Arthritis MRI Scoring (JAMRIS) system. Additionally, the presence of joint fluid was evaluated. No cartilage lesions or bone abnormalities were observed. RESULTS: We included 57 healthy children. The overall mean thickness of the normal synovial membrane was 0.4 mm (min-max; 0.0-1.8mm). The synovium was thickest around the cruciate ligaments and retropatellar and suprapatellar regions. The mean overall diameter of the largest pocket of joint fluid was 2.8 mm (min-max; 0.9-8.0mm). Bone marrow changes were observed in three children (all in the apex patellae). CONCLUSIONS: The normal synovial membrane was maximally 1.8 mm thick, indicating that the JAMRIS cut-off value of 2 mm can be considered a valid measure for evaluating synovial hypertrophy. Some joint fluid and bone marrow changes suggestive of bone marrow oedema in the apex patellae can be seen in healthy children. KEY POINTS: • Knowledge on the normal synovial appearance using contrast-enhanced MR is lacking. • In healthy children, normal synovial membrane is maximally 1.8 mm thick. • Normal synovium is thickest around the cruciate ligaments, retropatellar and suprapatellar. • Bone marrow oedema in the apex patellae is seen in healthy children.

Construct validity of pixel-by-pixel DCE-MRI: Correlation with conventional MRI scores in juvenile idiopathic arthritis.

OBJECTIVES: To assess the capability of the pixel-by-pixel DCE-MRI time intensity curve (TIC)-shape analysis method in the evaluation of juvenile idiopathic arthritis (JIA) disease activity by correlating DCE-MRI parameters with semi-quantitative conventional-MRI scores of synovitis. METHODS: Clinical, laboratory, and (DCE)-MRI datasets of 85 JIA patients were prospectively obtained. TIC-shapes of each voxel were classified into one of seven predefined color-coded TIC shape categories. Spatial information on the relative amount of TIC-shapes, maximal enhancement (ME), maximal initial slope (MIS), initial area under the curve (iAUC), time-to-peak (TTP), enhancing volume (EV) was calculated of the synovial membrane. The grade of synovitis was scored on conventional MR images by two readers using the validated JAMRIS system. The Bonferroni method was used to correct for multiple testing, therefore, a P value of <0.0056 is considered significant (0.05/9=0.0056). RESULTS: The semi-quantitative JAMRIS synovitis score correlated substantially with the ME, EV, and iAUC (Rs=0.658, P<0.001; Rs=0.618, P<0.001; Rs=0.639, P<0.001), and moderately with MIS (Rs=0.453, P<0.001). A poor correlation was observed between the relative number of TIC-shapes 2-5 and the JAMRIS synovitis score (Rs=0.209, P=0.054; Rs=0.328, P=0.002; Rs=0.241, P=0.023; Rs=-0.241, P=0.026). CONCLUSION: In this explorative study, both TIC shape and semi-quantitative DCE-MRI analysis methods showed moderate to substantial correlations with conventional MRI scores of disease activity, indicating that this methods are feasible. Further research is warranted whether DCE-MRI holds potential to become an objective and quantitative method for the evaluation of disease activity in JIA.

Diffusion-weighted imaging for assessment of synovial inflammation in juvenile idiopathic arthritis: a promising imaging biomarker as an alternative to gadolinium-based contrast agents.

OBJECTIVES: To compare dynamic-contrast-enhanced MRI (DCE) and diffusion-weighted imaging (DWI) in quantifying synovial inflammation in juvenile idiopathic arthritis (JIA). METHODS: Regions of interest (ROI) were drawn in the synovium of JIA patients on T1 DCE and T2 DWI, followed by extraction of the maximum enhancement (ME), maximum initial slope (MIS), time to peak (TTP), % of different time intensity curve shapes (TIC) and apparent diffusion coefficient (ADC) of the ROIs. Mann-Whitney-U test was used for comparing parameters between MRI-active and -inactive patients (defined by the juvenile arthritis MRI scoring system). Spearman's rank was used to analyse the correlation between DCE and DWI. RESULTS: Thirty-five JIA patients (18 MRI active and 17 MRI inactive) were included. Median age was 13.1 years and 71% were female. ME, MIS, TTP, % TIC 5 and ADC were significantly different in MRI-active versus MRI-inactive JIA with median ADC 1.49 × 10-3mm2/s in MRI-active and 1.25 × 10-3mm2/s in MRI-inactive JIA, p = 0.001, 95% confidence interval of difference in medians =0.11-0.53 × 10-3mm2/s. ADC correlated to ME, MIS and TIC 5 shapes (r = 0.62, r = 0.45, r = -0.51, respectively, all p < 0.05). CONCLUSIONS: Similar to DCE parameters, DWI-derived ADC is significantly different in MRI-active JIA as compared to MRI-inactive JIA. The non-invasiveness of DWI combined with its possibility to detect synovial inflammation shows the potential of DWI. KEY POINTS: • MRI can quantify: dynamic contrast-enhanced and diffusion-weighted MRI can quantify synovitis • Both DWI and DCE can differentiate active from inactive JIA • The DWI-derived apparent diffusion coefficient (ADC) is higher in active JIA • DWI is non-invasive and thus safer and more patient-friendly • DWI is a potentially powerful and non-invasive imaging biomarker for JIA.