[Pitfalls of hematopoietic growth factors on MR images]

We report the effects of hematopoietic growth factors on MR signal intensity of bone marrow in 2 children undergoing chemotherapy for musculoskeletal malignancies. The two patients with initially fatty marrow had signal intensity changes: diffuse decreased signal of the distal femoral metaphysis and patchy areas in the diaphysis of both tibia and fibula, simulating metastases. These changes coincided with dramatic increase in neutrophil counts. Technetium 99 skeletal scintigraphy was normal. After a three year follow-up the patients are in good health.