Bone marrow reconversion

Bone marrow reconversion generates a red bone marrow pattern that is in reverse to the normal red-to-yellow distribution. 

Pathology

Bone marrow reconversion occurs when there is increased hematopoietic demand, which may be ^1,2:

• physiological

  • cigarette smoking

  • obesity

  • high endurance athletes

  • high altitude

• iatrogenic

  • post granulocyte-colony stimulating factor treatment

  • post erythropoietin treatment

• pathological

  • severe chronic anemia, e.g. sickle cell disease, thalassemia, hereditary spherocytosis

  • diabetes mellitus

  • chronic respiratory disease

Radiographic features

MRI

Signal intensity will be that of normal red marrow being low T1 signal but still higher than skeletal muscle ^1,3. In the appendicular skeleton, it tends to be symmetrical and homogeneous, whereas in the axial skeletal it can be heterogeneous/multifocal ¹. Marrow reconversion occurs in the reverse order of normal red to yellow marrow conversion ⁴.

Differential diagnosis

• if homogeneous consider diffuse marrow infiltration ¹

• if heterogeneous consider ¹

  • skeletal metastases

  • multiple myeloma