Follow-up MRI after RFA of a subphyseal femoral osteoid osteoma of the femur. A sagittal T1W MRI (A) shows an area of coagulation necrosis (arrow) surrounding the nidus (arrowhead). A coronal contrast-enhanced T1W MRI with fat suppression (B) shows a hypointense perfusion defect (arrow) surrounded by a thin enhancing rim (arrowhead)