Diffuse serous atrophy of bone marrow occurs in anorexia nervosa, chronic renal insufficiency, thyroid disease, tuberculosis, HIV, and cachexia related to malignancy. It refers to depletion of red and yellow marrow, absence of marrow fat, and accumulation of hyaluronic acid in the marrow spaces. The increased free water content leads to prolonged T1 and T2 relaxation times. T1W images show intermediate marrow signal while T2W images show very high signal intensity. The typical progression of serous atrophy is from the distal extremities to the proximal extremities and axial skeleton.
Vande Berg BC, Malghem J, Devuyst O, et al. Anorexia nervosa: correlation between MR appearance of bone marrow and severity of disease. Radiology 1994;193:859-64.