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

OBJECTIVE

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

METHODS

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.

RESULTS

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).

CONCLUSION

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