Reliability of CEUS and MRI for grading knee-joint inflammation in juvenile idiopathic arthritis

Sílvia Costa Dias; Catarina Costa Ferreira; Inês Santos; Miguel Castro; Mariana Rodrigues; Francisca Aguiar; Cláudia Camila Dias; Bac Nguyen; Vitor Silva; Isabel Ramos; Damjana Ključevšek; Iva Brito; Karen Rosendahl

doi:10.1007/s00330-026-12627-z

Reliability of CEUS and MRI for grading knee-joint inflammation in juvenile idiopathic arthritis

Eur Radiol. 2026 May 15. doi: 10.1007/s00330-026-12627-z. Online ahead of print.

Authors

Sílvia Costa Dias^{1

2}, Catarina Costa Ferreira³, Inês Santos⁴, Miguel Castro³, Mariana Rodrigues⁵, Francisca Aguiar⁵, Cláudia Camila Dias^{6

7}, Bac Nguyen⁸, Vitor Silva³, Isabel Ramos⁹, Damjana Ključevšek¹⁰, Iva Brito^{9

5}, Karen Rosendahl^{11

12}

Affiliations

¹ Department of Medicine, Faculty of Medicine of the University of Porto (FMUP), Porto, Portugal. silviacostadias@hotmail.com.
² Department of Radiology, University Hospital Centre of São João Porto (CHUSJ), Porto, Portugal. silviacostadias@hotmail.com.
³ Department of Radiology, University Hospital Centre of São João Porto (CHUSJ), Porto, Portugal.
⁴ Rheumatology Unit, Unidade Local Saúde Viseu Dão-Lafões, Viseu, Portugal.
⁵ Paediatric and Young Adult Rheumatology Unit, University Hospital Centre of São João (CHUSJ), Porto, Portugal.
⁶ Knowledge Management Unit, Faculty of Medicine of the University of Porto (FMUP), Porto, Portugal.
⁷ CINTESIS@RISE, Department of Community Medicine, Information and Health Decision Sciences (MEDCIDS), Faculty of Medicine of the University of Porto (FMUP), Porto, Portugal.
⁸ Division of Radiology and Nuclear Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
⁹ Department of Medicine, Faculty of Medicine of the University of Porto (FMUP), Porto, Portugal.
¹⁰ Department of Radiology, University Children's Hospital Ljubljana, Ljubljana, Slovenia.
¹¹ Department of Clinical Medicine, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway.
¹² Section of Paediatric Radiology, University Hospital of North Norway, Tromsø, Norway.

PMID: 42141288
DOI: 10.1007/s00330-026-12627-z

Abstract

Objective: To examine the reliability of contrast-enhanced MRI (CEMRI) and contrast-enhanced ultrasound (CEUS) for grading arthritis.

Materials and methods: Prospective study on 1-18-year-olds with juvenile idiopathic arthritis (JIA), performed during 2023/2024. All had CEUS and CEMRI of the knee on the same day. Two observers independently scored the US-video-clip for inflammation (0-3 scale), with a second reading after 6 weeks. Using VueBox®, peak enhancement (PE), time to peak (TTP) and wash-in area under the curve (WiAUC) were measured by both observers, separately. The MRIs were scored for inflammation (0-3 scale) twice by two observers. Peak enhancement intensity (PEI), TTP and initial area under the curve (iAUC) (Syngo.via®) were measured.

Results: Fifty-two patients (35 females), median age 12.4 years (IQR 8.9-15.6 years), were included. CEUS showed almost perfect intra/interreader agreement for the degree of overall inflammation (intrareader kappa 0.90 [0.83-0.98], interreader kappa 0.85 [0.76-0.93]). Interreader PE and WiAUC agreement was excellent (ICC 0.99 [95% CI 0.99-1.00] and 0.97 [95% CI 0.95-0.98], respectively), while TTP performed moderately (ICC 0.66 [95% CI 0.40-0.80]). On CEMRI, intra/interreader agreement for overall synovial inflammation was almost perfect (intrareader kappa 0.94 [95% CI 0.88-1.00]; interreader kappa 0.92 [95% CI 0.85-1.00]). Interreader PEI and iAUC agreement was excellent (ICC 0.99 [95% CI 0.98-0.99] and 0.98 [95% CI 0.97-0.99], respectively), while TTP had good agreement (ICC 0.76 [95% CI 0.59-0.86]).

Conclusion: Subjective grading of synovial inflammation on a 0-3 scale demonstrated high reliability for both CEUS and CEMRI. Both methods have excellent relative reliability (ICC) for quantitative measurements; however, their absolute precision (LoA) is poor.

Key points: Question Are CEUS and CEMRI reliable tools to grade the activity of knee-joint arthritis in children with juvenile idiopathic arthritis? Findings Subjective grading of arthritis performed well within and between observers for both CEUS and CEMRI. Both methods provide reliable dynamic measurements; however, their precision is poor. Clinical relevance CEUS offers high-precision, real-time imaging for grading active knee-joint inflammation in children with juvenile idiopathic arthritis, with future potential to replace the current standard of CEMRI.

Keywords: Arthritis; Knee; Magnetic resonance imaging; Synovitis; Ultrasonography.