**6.1 Transient osteoporosis**

Transient osteoporosis of the hip, also called transient marrow edema syndrome, is characterized by the presence of intense radionuclide uptake in the femoral head, which may extend to the femoral neck, to the intertrochanteric region, or to proximal femoral diaphyseal region. It is also typical to find hyperactivity at the images of flow phase and blood pool phase. Ischemia of the femoral head, that has not caused necrosis, has been suggested as a possible cause of this process. The reactive hyperemic response to this ischemic phenomenon, with a repair process, would explain scintigraphic changes. Insufficiency fractures in this location can provide similar scintigraphic imaging (Schneider, 2006).
