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ObjectiveTo standardize and improve the accuracy of detection of arthritis by thermal imaging.MethodsChildren with clinically active arthritis in the knee or ankle, as well as healthy controls, were enrolled to the development cohort; another group of children with knee symptoms was enrolled to the validation cohort. Ultrasound was performed in the arthritis subgroup for the development cohort. Joint exam by certified rheumatologists was used as a reference for the validation cohort. Infrared thermal data were analyzed using custom software. Temperature after within-limb calibration (TAWiC) was defined as the temperature differences between joint and ipsilateral mid-tibia. TAWiC of knees and ankles was evaluated using ANOVA across subgroups. Optimal thresholds were determined by receiver-operating characteristic analysis using Youden index.ResultsThere were significant differences in mean and 95th TAWiC of knee in anterior, medial, lateral views, and of ankles in anterior view, between inflamed and uninflamed counterparts (P < 0.05). The area under the curve was higher by 30% when using TAWiCknee than that when using absolute temperature. Within the validation cohort, the sensitivity of accurate detection of arthritis in the knees using both mean and 95th TAWiC from individual views or all 3 views combined ranged from 0.60 to 0.70, and the specificity was > 0.90 in all views.ConclusionChildren with active arthritis or tenosynovitis in knees or ankles exhibited higher TAWiC than healthy joints. Our validation cohort study showed promise for the clinical utility of infrared thermal imaging for arthritis detection.

ObjectiveChronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory bone disease that is gaining recognition from clinicians and researchers. We aim to publish data from our cohort of patients with CNO living in the northwestern United States to increase the awareness of specific demographics, characteristics, and presentation of this rare disease.MethodsA retrospective chart review was performed of our electronic medical records. Patients with complete chart records who met criteria for a diagnosis of CNO from 2005 to 2019 were included. Extracted data including patient demographics, bone biopsy results, and lesion locations on advanced imaging were analyzed. King County census data were used to calculate the annual new case rate within our center.ResultsA total of 215 CNO cases were diagnosed at our large tertiary pediatric hospital. The majority of cases were of White race residing in Washington’s most populous county, King County. Most cases were diagnosed in 2016 to 2019, showing a significant increase in the annual case rate from 8 to 23 per million children in King County, though there did not appear to be a seasonal predilection. Biopsy rate decreased from 75% to 52%. One hundred fifty-two (71%) children had family history of autoimmunity. With increasing use of whole-body magnetic resonance imaging (WB-MRI), results showed 68% had multiple lesions.ConclusionCNO has been diagnosed at an increased rate in recent years. WB-MRI may assist in identifying other lesions that may be asymptomatic on presentation. Bone biopsy is still required in some children at the time of diagnosis.

Objective.The validity of our current definitions for clinically inactive disease (CID) in juvenile idiopathic arthritis (JIA) based on physical examination is challenged by the development of advanced musculoskeletal imaging tools. We aimed to prospectively determine the prevalence of abnormal ultrasound (US) findings in children with CID in JIA and their clinical significance.Methods.Children aged ≥ 4 years with CID and a history of arthritis from a single tertiary center were approached over 1 year. Standard US of knees, tibiotalar joints, subtalar joints, and wrists were performed at baseline and at a followup visit. US images were scored by 2 pediatric musculoskeletal radiologists.Results.Forty children with CID were enrolled and followed clinically. The median duration of inactive disease was 1 year. The most common International League of Associations for Rheumatology JIA categories were extended oligoarticular JIA (30%) and rheumatoid factor–negative polyarthritis (38%). At baseline, among a total of 289 joints scanned, 24 joints (8%) had at least 1 abnormal finding in 18 (45%) of 40 subjects. When evaluated at the individual joint level against flares identified during followup exams, these baseline US findings had a sensitivity of 15% and a positive predictive value of 12%. The predictive performance of the second US was even less.Conclusion.Our study demonstrates that nearly half of children with CID had abnormal US findings in 1 of 8 commonly affected joints. These findings did not correlate with subsequent clinical flares in up to 2 years of followup.

We thank Dr. Johannes Roth for his comments1 on our recent publication2. Dr. Roth raises several important points. The first is that for a Doppler signal to be considered abnormal it must exist within thickened synovium. This is based on adult studies and a recent consensus conference defining ultrasound (US) requirements for the pediatric population3. Physiologic blood flow may exist within the joint space of children without abnormal structural changes of the synovium. Thus, if these new definitions of Doppler signal detection in synovitis for children are applied to the images for our study, the presence of synovitis would have been much less frequent in … Address correspondence to Dr. Y. Zhao, MA 7.110, 4800 Sand Point Way NE, Seattle, Washington 98105, USA. E-mail: yongdong.zhao{at}seattlechildrens.org