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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Dynamic contrast-enhanced magnetic resonance imaging of the wrist in children with juvenile idiopathic arthritis.

BACKGROUND: Dynamic contrast-enhanced MRI provides information on the heterogeneity of the synovium, the primary target of disease in children with juvenile idiopathic arthritis (JIA). OBJECTIVE: To evaluate the feasibility of dynamic contrast-enhanced MRI in the wrist of children with JIA using conventional descriptive measures and time-intensity-curve shape analysis. To explore the association between enhancement characteristics and clinical disease status. MATERIALS AND METHODS: Thirty-two children with JIA and wrist involvement underwent dynamic contrast-enhanced MRI with movement-registration and were classified using validated criteria as clinically active (n = 27) or inactive (n = 5). Outcome measures included descriptive parameters and the classification into time-intensity-curve shapes, which represent the patterns of signal intensity change over time. Differences in dynamic contrast-enhanced MRI outcome measures between clinically active and clinically inactive disease were analyzed and correlation with the Juvenile Arthritis Disease Activity Score was determined. RESULTS: Comprehensive evaluation of disease status was technically feasible and the quality of the dynamic dataset was improved by movement registration. The conventional descriptive measure maximum enhancement differed significantly between clinically active and inactive disease (P = 0.019), whereas time-intensity-curve shape analysis showed no differences. Juvenile Arthritis Disease Activity Score correlated moderately with enhancing volume (P = 0.484). CONCLUSION: Dynamic contrast-enhanced MRI is a promising biomarker for evaluating disease status in children with JIA and wrist involvement. Conventional descriptive dynamic contrast-enhanced MRI measures are better associated with clinically active disease than time-intensity-curve shape analysis.

Contrast-enhanced MRI of the knee in children unaffected by clinical arthritis compared to clinically active juvenile idiopathic arthritis patients.

OBJECTIVES: To evaluate enhancing synovial thickness upon contrast-enhanced magnetic resonance imaging (MRI) of the knee in children unaffected by clinical arthritis compared with clinically active juvenile idiopathic arthritis (JIA) patients. A secondary objective was optimization of the scoring method based on maximizing differences on MRI between these groups. METHODS: Twenty-five children without history of joint complaints nor any clinical signs of joint inflammation were age/sex-matched with 25 clinically active JIA patients with arthritis of at least one knee. Two trained radiologists, blinded for clinical status, independently evaluated location and extent of enhancing synovial thickness with the validated Juvenile Arthritis MRI Scoring system (JAMRIS) on contrast-enhanced axial fat-saturated T1-weighted MRI of the knee. RESULTS: Enhancing synovium (≥2 mm) was present in 13 (52 %) unaffected children. Using the total JAMRIS score for synovial thickening, no significant difference was found between unaffected children and active JIA patients (p = 0.091). Additional weighting of synovial thickening at the JIA-specific locations enabled more sensitive discrimination (p = 0.011). CONCLUSIONS: Mild synovial thickening is commonly present in the knee of children unaffected by clinical arthritis. The infrapatellar and cruciate ligament synovial involvement were specific for JIA, which-in a revised JAMRIS-increases the ability to discriminate between JIA and unaffected children. KEY POINTS: • Synovial inflammation is the primary disease feature in juvenile idiopathic arthritis (JIA). • Appearance of the synovium on contrast-enhanced MRI in unaffected children is unknown. • Validation of existing scoring methods requires comparison between JIA and unaffected children. • Mild enhancing synovial thickening was detected in half of the unaffected children. • Location-weighting for JIA-specific locations increased discriminative value of the scoring methods (p = 0.011).

The many shades of enhancement: timing of post-gadolinium images strongly influences the scoring of juvenile idiopathic arthritis wrist involvement on MRI.

BACKGROUND: Potential long-term side effects of treatment for juvenile idiopathic arthritis are concerning. This has necessitated accurate tools, such as MRI, to monitor treatment response and allow for personalized therapy. OBJECTIVE: To examine the extent to which timing of post-contrast MR images influences the scoring of inflammatory change in the wrist in children with juvenile idiopathic arthritis. MATERIALS AND METHODS: We studied two sets of post-contrast 3-D gradient echo MRI series of the wrist in 34 children with juvenile idiopathic arthritis. These images were obtained immediately after administration of intravenous contrast material and again after approximately 10 min. The dataset was drawn from a prospective multicenter project conducted 2006-2010. We assessed five wrist locations for synovial enhancement, effusion and overall inflammation. Examinations were scored by one radiologist in two sessions - the first was based on the early post-contrast images, and the later session, for which the previous findings were masked, was based on the later post-contrast images. RESULTS: Fifty-two of the 170 locations (30.6%) received a higher synovial enhancement score based on the late post-contrast images as compared to the early images. Sixty of the 170 (35%) locations received a higher total inflammation score. The mean scores of synovial enhancement and total inflammation were significantly higher when based on the late post-contrast images as compared to the early post-contrast images. CONCLUSION: An MRI-based scoring system for the presence and degree of synovitis should be based on a standardized MR-protocol with a fixed interval between intravenous contrast injection and post-contrast images.

Contrast-enhanced MRI features in the early diagnosis of Juvenile Idiopathic Arthritis.

OBJECTIVES: To determine whether clinical, laboratory or Magnetic Resonance Imaging (MRI) measures differentiate Juvenile Idiopathic Arthritis (JIA) from other forms of active childhood arthritis. MATERIALS AND METHODS: We prospectively collected data of 80 treatment-naïve patients clinically suspected of JIA with active non-infectious arthritis of (at least) one knee for <12 months duration. Upon presentation patients underwent clinical and laboratory assessments and contrast-enhanced MRI. MRI was not used as a diagnostic criterion. RESULTS: Forty-four (55%) patients were clinically diagnosed with JIA, whereas in 36 (45%) patients the diagnosis of JIA was discarded on clinical or laboratory findings. MRI-based synovitis was present in 27 (61.4%) JIA patients and in 7 (19.4%) non-JIA patients (P < 0.001). Five factors (male gender, physician's global assessment of overall disease activity, joints with limited range of motion, HLA-B27, MRI-based synovitis) were associated with the onset of JIA. In multivariate analysis MRI-based synovitis proved to be independently associated with JIA (OR 6.58, 95% CI 2.36-18.33). In patients with MRI-based synovitis, the RR of having JIA was 3.16 (95% CI 1.6-6.4). CONCLUSIONS: The presence of MRI-based synovitis is associated with the clinical onset of JIA. Physical examination could be supported by MRI, particularly to contribute in the early differentiation of different forms of non-infectious childhood arthritis. KEY POINTS: • Juvenile Idiopathic Arthritis (JIA) is a diagnosis of exclusion. • Differentiating JIA and other forms of childhood arthritis can be difficult. • MRI-techniques have substantially improved evaluation of joint abnormalities in JIA patients. • MRI-based synovitis is significantly associated with the clinical onset of JIA. • MRI could support physical examination in the early differentiation of childhood arthritis.

Frequency of joint involvement in juvenile idiopathic arthritis during a 5-year follow-up of newly diagnosed patients: implications for MR imaging as outcome measure.

To assess the sequence and type of active joints in a cohort of newly diagnosed juvenile idiopathic arthritis (JIA) patients with full access to current treatment at first visit and during a follow-up period of 5-years, in order to identify an index joint/group of joints for magnetic resonance imaging in JIA. Patient charts of all consecutive newly diagnosed JIA patients with a follow-up duration of at least 5 years were analyzed. Patients were derived from two tertiary pediatric rheumatology centers. Patient characteristics and data concerning the presence of joints with arthritis and the use of medication were recorded. Findings from 95 JIA patients [39 (41 %) oligoarticular and 56 (59 %) polyarticular] were analyzed. At first visit, distribution of active joints among patients was as follows: knee (n = 70, 74 %), ankle (n = 55, 58 %), elbow (n = 23, 24 %), wrist (n = 23, 24 %), metacarpophalangeal (MCP) (n = 20, 21 %), proximal interphalangeal (PIP) (n = 13, 14 %), hip (n = 6, 6 %), shoulder (n = 5, 5 %), and distal interphalangeal (DIP) (n = 4, 4 %) joints. After a follow-up period of 5 years, the cumulative percentage of patients with specific joint involvement changed into: knee (n = 88, 93 %), ankle (n = 79, 83 %), elbow (n = 43, 45 %), wrist (n = 38, 40 %), MCP (n = 36, 38 %), PIP (n = 29, 31 %), shoulder (n = 20, 21 %), hip (n = 17, 19 %), and DIP (n = 9, 10 %) joints. Despite changes in treatment strategies over the years, the knee remains the most commonly involved joint at onset and during follow-up in JIA, followed by the ankle, elbow, and wrist. For the evaluation of outcome with MRI, the knee appears the most appropriate joint in JIA.

Feasibility of diffusion-weighted magnetic resonance imaging in patients with juvenile idiopathic arthritis on 1.0-T open-bore MRI.

OBJECTIVE: To evaluate the feasibility of non-invasive diffusion-weighted imaging (DWI) of the knee of children with juvenile idiopathic arthritis (JIA) and, further, to analyze the apparent diffusion coefficient (ADC) levels to distinguish synovium from effusion. MATERIALS AND METHODS: Standard magnetic resonance imaging of the knee including post-contrast imaging was obtained in eight patients (mean age, 12 years 8 months, five females) using an open-bore magnetic resonance imaging system (1.0 T). In addition, axially acquired echo-planar DWI datasets (b-values 0, 50, and 600) were prospectively obtained and the diffusion images were post-processed into ADC50-600 maps. Two independent observers selected a region of interest (ROI) for both synovium and effusion using aligned post-contrast images as landmarks. Mann-Whitney U test was performed to compare ADC synovium and ADC effusion. RESULTS: DWI was successfully obtained in all patients. When data of both observers was combined, ADC synovium was lower than ADC effusion in the ROI in seven out of eight patients (median, 1.92 × 10(-3) mm(2)/s vs. 2.40 × 10(-3) mm(2)/s, p = 0.006, respectively). Similar results were obtained when the two observers were analyzed separately (observer 1: p = 0.006, observer 2: p = 0.04). CONCLUSIONS: In this pilot study, on a patient-friendly 1.0-T open-bore MRI, we demonstrated that DWI may potentially be a feasible non-invasive imaging technique in children with JIA. We could differentiate synovium from effusion in seven out of eight patients based on the ADC of synovium and effusion. However, to select synovium and effusion on DWI, post-contrast images were still a necessity.

Pixel-by-pixel analysis of DCE-MRI curve shape patterns in knees of active and inactive juvenile idiopathic arthritis patients.

OBJECTIVES: To compare DCE-MRI parameters and the relative number of time-intensity curve (TIC) shapes as derived from pixel-by-pixel DCE-MRI TIC shape analysis between knees of clinically active and inactive juvenile idiopathic arthritis (JIA) patients. METHODS: DCE-MRI data sets were prospectively obtained. Patients were classified into two clinical groups: active disease (n = 43) and inactive disease (n = 34). Parametric maps, showing seven different TIC shape types, were created per slice. Statistical measures of different TIC shapes, maximal enhancement (ME), maximal initial slope (MIS), initial area under the curve (iAUC), time-to-peak (TTP), enhancing volume (EV), volume transfer constant (K(trans)), extravascular space fractional volume (V(e)) and reverse volume transfer constant (k(ep)) of each voxel were calculated in a three-dimensional volume-of-interest of the synovial membrane. RESULTS: Imaging findings from 77 JIA patients were analysed. Significantly higher numbers of TIC shape 4 (P = 0.008), median ME (P = 0.015), MIS (P = 0.001) and iAUC (P = 0.002) were observed in clinically active compared with inactive patients. TIC shape 5 showed higher presence in the clinically inactive patients (P = 0.036). CONCLUSIONS: The pixel-by-pixel DCE-MRI TIC shape analysis method proved capable of differentiating clinically active from inactive JIA patients by the difference in the number of TIC shapes, as well as the descriptive parameters ME, MIS and iAUC. KEY POINTS: • The pixel-by-pixel TIC shape method differentiates clinically active and inactive JIA patients • Significantly higher numbers of TIC shape 4 were observed in clinically active patients • DCE-MRI parameters ME, MIS and iAUC differ between active and inactive patients • The pixel-by-pixel analysis method allows direct visualization of the heterogeneously distributed disease • The DCE-MRI TIC shape method may serve as a quantitative outcome measure.

Distribution pattern of MRI abnormalities within the knee and wrist of juvenile idiopathic arthritis patients: signature of disease activity.

OBJECTIVE: The aim of this study in clinically active juvenile idiopathic arthritis (JIA) was to assess the frequency and distribution pattern of synovitis as hallmark of disease and additional soft-tissue and bony abnormalities on MRI in the knee and wrist as two target joints. MATERIALS AND METHODS: MRI datasets of 153 clinically active JIA patients (110 with knee and 43 with wrist involvement) were evaluated independently by two readers for the presence of literature-based imaging features: "synovial hypertrophy," "bone marrow changes," "bone erosions," "tenosynovitis" (only in the wrist), and "cartilage lesions" (only in the knee) in accordance with validated definitions and scoring locations. RESULTS: Synovial hypertrophy was most frequently observed--both in the knee and in the wrist (61.8-65.1% of cases). For the knee, the most frequently involved locations were the cruciate ligaments (46/183 locations [25.1%] affected with synovial hypertrophy) and medial patella (18/62 locations [29.0%] with bone marrow changes). Cartilage lesions and bone erosions were rare (5.5-7.3% of cases). For the wrist, most frequently involved were the radiocarpal joint (21/64 locations [32.8%] with synovial hypertrophy), lunate (7/46 locations [15.2%] with bone marrow changes), and capitate or triquetrum (6/28 locations [21.4%] with bone erosions). Tenosynovitis was a common wrist-specific feature (46.5% of cases). MRI showed no abnormalities in a subgroup of patients with clinically active knee (23.6%) and wrist (16.3%) involvement. CONCLUSION: The distribution pattern of MRI abnormalities in the knee and wrist of active JIA patients provides a practical tool to detect a signature of JIA disease activity in target joints.

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.