Fig. 4

MRI of hips and sacroiliac joints of FOP patients during the study. A – active sacroiliitis in 18 years old male patient before tofacitinib therapy (the subchondral bone marrow edema noted by the arrows). B – the same patient after 1 year of tofacitinib treatment (reduction of the subchondral bone marrow edema, arrows). C – MRI evidence of bilateral hips effusion in 12 years old male patient before tofacitinib therapy (arrows). D – the same patient 1.5 years after tofacitinib treatment, regression of synovial effusion in the hip joints (arrows)