Osteoporosis is associated with increased marrow fat content and decreased marrow fat unsaturation: a proton MR spectroscopy study.
OBJECTIVE
To use proton magnetic resonance spectroscopy ((1)H-MRS) to evaluate vertebral marrow fat, and to determine whether bone density correlates with fat content and fat unsaturation levels in postmenopausal women.


METHODS
Fifty-three women (mean age = 70 years) underwent dual energy x-ray absorptiometry and (1)H-MRS, and 12 young female controls (mean age = 28 years) underwent (1)H-MRS of the lumber spine. Water and lipid peak amplitudes were measured to calculate fat content and fat unsaturation index. Spearman's correlation tests and a t-test comparison of means were applied.


RESULTS
(1)H-MRS was successful in 15 normal, 15 osteopenic, and 20 osteoporotic subjects, and in all controls. Marrow fat content was significantly elevated in osteoporotic (65.5% +/- 10%) and osteopenic (63.5% +/- 9.3%) subjects compared to normal subjects (56.3% +/- 11.2%) and young controls (29% +/- 9.6%). The fat unsaturation index was significantly decreased in osteoporotic (0.091 +/- 0.013) and osteopenic (0.097 +/- 0.014) subjects compared to normal subjects (0.114 +/- 0.016) and young controls (0.127 +/- 0.031). A good inverse correlation was observed between the fat content and the unsaturation index (r(s) = -0.53, P < 0.0001).


CONCLUSIONS
Osteoporosis is associated with increased marrow fat. As marrow fat increases, saturated lipids appear to increase preferentially to unsaturated lipids.
Yeung
David K W
DK
Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing Street, Shatin, Hong Kong SAR, China. dkyeung@cuhk.edu.hk
Griffith
James F
JF
Antonio
Gregory E
GE
Lee
Francis K H
FK
Woo
Jean
J
Leung
Ping C
PC
D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology; D001853:Bone Marrow / Q000473:pathology*; D016022:Case-Control Studies; D005224:Fats, Unsaturated / Q000378:metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000150:complications / Q000175:diagnosis*; D019047:Phantoms, Imaging; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity
D005224:Fats, Unsaturated