Bone marrow diffuse T2 hypointense typicallyseen in the expansion of red marrow leading to the widening of medullary spaces and thinning of cortical bone. Also, red marrow conversion may occur in circumstances in which there is an increased oxygen requirement, such as in endurance athletes.When the hematopoietic capacity of the existing red marrow is exceeded, fatty marrow reconverts to red marrow. The pattern of reconversion is the reverse of that of physiologic marrow conversion, from axial to appendicular. Hematopoietic hyperplasia can result in diffusely T1-weighted hypointense signal in the axial skeleton . It is often seen with chronic anemia, such as sickle cell disease, thalassemia, and hereditary spherocytosis .You can ask your physician to rule out all the possible differential diagnosis.