Fig. 4

10-year-old child with CNO and a history of intermittent hip pain since he was 4 years old with elevated markers of inflammation under investigation for juvenile idiopathic arthritis. MRI of the pelvis showed bone marrow edema in the intertrochanteric periphyseal regions and in the sacroiliac joint (a), which was suggestive of CNO. WB-MRI was performed on the same day (b–f). Functional diffusion-weighted imaging (DWI) sequences (b and c) detected multiple lesions in the posterior elements of the thoracolumbar spine, sacroiliac joints and intertrochanteric regions, in addition to the distal metaphysis of the right femur and proximal metaphysis of the left fibula. The lesions are demonstrated in STIR morphological sequences as signal change with an edema pattern in the corresponding locations (d, e and f). HLA B27 was positive