RT Journal Article SR Electronic T1 Cartilage Thickness of the Knee Joint in Juvenile Idiopathic Arthritis: Comparative Assessment by Ultrasonography and Magnetic Resonance Imaging JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 534 OP 540 DO 10.3899/jrheum.140162 VO 42 IS 3 A1 Dan Østergaard Pradsgaard A1 Bente Fiirgaard A1 Anne Helen Spannow A1 Carsten Heuck A1 Troels Herlin YR 2015 UL http://www.jrheum.org/content/42/3/534.abstract AB Objective. The functional disability experienced in juvenile idiopathic arthritis (JIA) is primarily caused by joint effusion, synovial membrane hypertrophy, and periarticular soft tissue edema, leading to the degeneration of the osteocartilaginous structures because of the inflammatory process in the synovium. The ability to visualize the inflammatory changes and hence the ensuing osteocartilaginous degeneration is, therefore, of great importance in pediatric rheumatology. Ultrasonography (US) has been validated as a tool for measuring cartilage thickness in healthy children and, previously, we have found good agreement with the measures obtained by magnetic resonance imaging (MRI). Our aim is to validate and compare US with MRI measurements of distal femoral cartilage thickness in the knee joint at the medial condyle, lateral condyle, and intercondylar spots in children with JIA, and to locate the best spot for imaging comparisons. Methods. One knee from each of 23 children with oligoarticular JIA were investigated by both MRI and US. Outcome measures of imaging procedures were distal femoral cartilage thickness. Results. We found a high level of agreement between MRI and US measurements of mean cartilage thickness, and Rho values between modalities were high (between 0.70 and 0.86, p < 0.05 for all). We found a thinner cartilage thickness at the medial condyle in comparison to the other investigated points. Evaluation of anatomical landmarks for optimal measurement of cartilage thickness was found to be the intercondylar spot, which was easier to locate in addition to a smaller variance around the mean for that anatomical measuring point. Conclusion. US measurements of distal femoral cartilage thickness are highly correlated to MRI measurements. The intercondylar notch of the distal femoral cartilage may be the best anatomical point for cartilage thickness measurements of the knee. US is a reliant and nonexpensive, non-invasive modality for visualization of childhood femoral cartilage.