Computed tomography of spontaneous osteoporotic sacral fractures.

Spontaneous osteoporotic sacral fractures are an uncommon entity. They are difficult to image on plain films. Clinically, they may be confused with metastatic disease. A peculiar H-shaped uptake pattern on bone scan should suggest the condition, and CT can then demonstrate the fracture. In this case this combination of radionuclide scan and CT permitted differentiation of a sacral fracture from presumed bony metastases.