A previous study assessed 28 joints for US abnormalities in 40 JIA patients, and found that US synovitis scores (including synovial hyperplasia, joints effusion score, and PD-US score) correlated positively with pain VAS score, swollen joints count, tender joints count, ESR, CRP, and disease activity score-28 joints (DAS28)-CRP (14). Here, CRP is linked to synovitis.