Juvenile chronic arthritis of the hip: value of contrast-enhanced MR imaging

The purpose of this study was to assess the value of contrast-enhancement in MR diagnosis of hip joint disease in patients with juvenile chronic arthritis.

Fourteen hips in seven children (four girls, three boys; mean age, 11 years; range, 7-17 years) with juvenile chronic arthritis for a mean duration of seven years (range, 3-15 years) were imaged on a 0.5T MR unit. One patient had an MR scan repeated after an 8-month interval. Axial and coronal T1-weighted spin-echo, and axial gradient-echo sequences were performed. T1 weighted axial sequences were repeated immediately after 0.1 mmol/kg of intravenous gadopentetate dimeglumine. Patients were assessed clinically for pain in the hip, range of motion at the hip joint, haemoglobin and erythrocyte sedimentation rate. Two radiologists, unaware of the patients symptoms, jointly assessed the unenhanced and contrast-enhanced scans for synovial hypertrophy (pannus), cartilage destruction and joint effusion.

Pannus was underestimated on 75% of unenhanced MR scans (95% binomial confidence intervals 54% to 93%). Enhancing pannus was seen in 14 of the 16 hip MR scans. Enhancing pannus was associated with articular cartilage destruction in all cases, and joint pain in 13 of 14 scans. Joint effusions were overestimated on unenhanced scans in all cases. Pannus could only reliably be distinguished from joint effusion after contrast enhancement. Both cases of loculated joint effusion were only seen after contrast enhancement.

Contrast-enhancement is recommended to aid MR detection of disease activity and extent in children with juvenile chronic arthritis of the hip.