Fig. 2
Persisting synovitis of the left knee joint under anti-inflammatory treatment in a 20 year-old male patient (patient 2 in Table 2) with known juvenile idiopathic arthritis (JIA). a) Contrast-enhanced T1-weighted MRI section showes diffuse synovial thickening and contrast-enhancement (blue arrow) along with marked joint effusion (green arrow), b) corresponding DWI at b = 1000 s/mm2 delineates high signal synovial layer (blue arrow) from low signal effusion (green arrow). c) ADC-map, d) masked D-map with colour-encoded diffusion ranging 0 - 4 × 10¯3 mm/s2 and e) f-map with colour-encoded perfusion fraction ranging 0 - 80% demonstrate restricted diffusivity and increased perfusion fraction of the synovial layer (blue arrows)