Tc-99m nanocolloid and MRI evaluation of extramedullary hematopoiesis in thalassemia major.

Tc-99m nanocolloid bone marrow scintigraphy of a patient with thalassemia major showed a high degree hepatomegaly and active bone marrow throughout the skeleton with elevated radionuclide uptake in the cranium, the pelvis, and the proximal and distal ends of both tibiae. Areas of increased nanocolloid uptake in the right paravertebral and dorsal areas were associated with sites of extramedullary erythropoiesis. MRI identified the two intrathoracic masses in the chest.