Fig. 9

Osteoid osteoma versus calcar femorale stress fracture. (a–d) Male, 35 years old, presenting with hip pain for 3 months. MRI T1 (a) and T2 FS (b) showed bone marrow edema on the femoral neck (arrowhead), T1 FS GD (c) and CT (d) showed a small nonmineralized nidus (arrows) with gadolinium enhancement (c) and mild cortical thickening (dotted arrow in d). (e–h) Male, 33-year-old runner, presenting with hip pain for 2 weeks, which worsened during running workouts. MRI T1 (e) and T2 FS (f, g) showed bone marrow edema on the lower femoral neck (arrowhead) and a cortical fracture line (arrows), which was also seen on the CT scan (h)