[Magnetic resonance evaluations of correlation of iron overload and osteoporosis in ovariectomized rats]

To explore the correlation between liver T(2)(*) value and bone mineral density (BMD) in ovariectomized (OVX) rats.

A total of 60 rats, including sham (n = 25) and OVX (n = 35) groups, underwent dual-energy X-ray absorptiometry (DEXA) and liver magnetic resonance (MR)-T(2)(*) mapping for lumbar vertebra BMD and T(2)(*) values before and after operation monthly for 4 timepoints. Also micro-computed tomography (micro-CT) and biochemical measurements were performed. The sensitivity of liver T(2)(*) relaxation time detecting early osteoporosis were estimated and the correlation between liver T(2)(*) values and BMD analyzed.

BMD of lumber vertebra in OVX group decreased compared to control group at Month 2 postoperation ((554 ± 27) mg/cm³ vs (722 ± 19) mg/cm³, P < 0.05) in synchrony with an elevation of serum ferritin concentration ((521 ± 41) ng/ml vs (441 ± 29) ng/ml, P < 0.01) and liver iron concentration ((291 ± 18) µg/g vs (237 ± 27) µg/g, P < 0.01). A significant inter-group difference of liver T(2)(*) was detected at Month 1 postoperation ((13.2 ± 0.7) ms vs (13.9 ± 0.4) ms, P < 0.01). Liver T(2)(*) was significant positively correlated with BMD in sham group (r = 0.410, P < 0.01) and OVX group (r = 0.434, P < 0.01).

Liver T(2)(*) relaxation time may a valuable detection tool of assessing pathophysiological changes of osteoporosis in early stage.