Miriam Antoinette Bredella MD, Presenter: Nothing to Disclose

Pouneh Fazeli, Abstract Co-Author: Nothing to Disclose

Scott M. Daley, Abstract Co-Author: Nothing to Disclose

Karen K. Miller MD, Abstract Co-Author: Nothing to Disclose

Clifford J. Rosen, Abstract Co-Author: Nothing to Disclose

Anne Klibanski MD, Abstract Co-Author: Nothing to Disclose

Martin Torriani MD, Abstract Co-Author: Nothing to Disclose

Women with anorexia nervosa (AN) have increased marrow fat despite severe depletion of body fat. Recent studies have suggested that marrow fat composition may serve as a biomarker for bone quality. The purpose of our study was to investigate 1) marrow fat composition of the femur using proton MR spectroscopy (1H-MRS), and 2) the relationship between measures of marrow fat composition and BMD and body composition in women with AN and normal-weight controls.

The study was IRB approved and complied with HIPAA guidelines. Written informed consent was obtained from all subjects after the nature of the procedure had been fully explained.14 women with AN (29.5±1.9 years) and 12 normal-weight controls if similar age underwent 1H-MRS at 3.0T (Siemens Trio, Siemens Medical Systems, Erlangen, Germany) using a PRESS pulse sequence of the femoral diaphysis to determine total marrow fat content and marrow fat composition and of soleus muscle to determine intramyocellular lipids und unsaturated muscle lipids. MRI was performed to quantify abdominal fat, thigh fat and muscle. Lumbar spine BMD, fat and lean mass were assessed by DXA. 

Subjects with AN had higher marrow fat content (p<0.05), but similar marrow fat composition (p >0.05) compared to normal-weight controls. There was an inverse association between marrow methylene protons, an estimate of fatty acid (FA) saturated bonds, and lumbar spine BMD (r= -0.52, p=0.008) independent of %ideal body weight (%IBW) and total lipid content. Olefinic protons at 5.3 ppm, an estimate of FA unsaturated bonds, were inversely associated with body fat depots, independent of %IBW and total lipid content, and positively associated with soleus muscle unsaturation (p≤0.05).

Women with AN have higher total femoral marrow fat but similar composition compared to normal-weight controls. The degree of marrow FA saturation correlates inversely with BMD, suggesting that saturated lipids may have negative effects on BMD. The degree of marrow FA unsaturation correlates positively with soleus unsaturation, suggesting that marrow fat composition may be influenced by the same factors as ectopic lipid composition. 

Marrow fat composition assessed by 1H-MRS may serve as a biomarker for bone quality and metabolic risk.

Bredella, M, Fazeli, P, Daley, S, Miller, K, Rosen, C, Klibanski, A, Torriani, M, Marrow Fat Composition in Anorexia Nervosa.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006647.html