Right knee magnetic resonance image: joint effusion with synovitis signs. Patient presented with intense pain on the right knee, with increased capitation in bone scintigraphy, medial compartment tibiofemoral joint space narrowing and suprapatellar synovial bursa opacification in the radiograph. The magnetic resonance image showed joint effusion and signs of synovitis, indicated by both arrows in the figure, without any other alteration, along with the clinical picture, indicate active arthritis