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| The value of chemical shift MRI for evaluating osteoporosis |
| LEI Li-cun, HE Li, LIU Zhai, REN Qing-yun |
| Department of Radiology, the First Hospital of Hebei University, Shijiazhuang 050031, China |
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Abstract Objective: To investigate the value of MRI chemical-shift sequences in evaluating fat content of bone marrow for staging of osteoporosis. Materials and Methods: Seventy patients were given dual energy X-ray absorptiometry examination(DXA), conventional MRI, and chemical shift MRI. According to the T-score of DXA at the lumbar spine and hip, the patients were divided into normal bone density, osteopenia and osteoporosis groups. In order to calculate fat content in bone marrow, the signal intensity of lumbar verbebral bodies(L1~L4) was measured on in-phase and out-of-phase sequences of chemical-shift MRI. Fat content was calculated through signal decline index of the vertebral bodies. The quantitative values were compared with these results of bone density obtained from DXA examination at the lumbar spine and the hip. Correlation analysis was conducted between the signal decline index of the vertebrae and bone density values at lumbar and femoral neck respectively. Results: According to the groups divided by DXA at the spine, the median signal decline index of the vertebral bodies of the 3 groups, normal, osteopenia and osteoporosis groups, was 59.73%(21.84%~72.35%), 59.64%(21.55%~78.42%), 57.04%(34.77%~77.30%) respectively. There were statistical differences between osteoporosis and normal group(P<0.001), and between the osteoporosis and osteopenia group(P<0.001), no statistical difference between normal and osteopenia group(P=0.685). According to the groups divided by DXA at the hips, the median vertebral signal decline index of the three groups was 62.41%(21.84%~77.63%), 58.39%(40.96%~78.42%), and 54.76%(21.55%~77.30%) respectively. There was statistical difference among the groups (P<0.001). The signal decline index of lumbar vertebrae was significantly positively correlated to the value of femoral neck bone mineral density(r=0.351, P=0.004). There was no statistically significant correlation(P=0.379) between the value of lumbar spine mineral density and lumbar spine signal decline index. Conclusion: Vertebral fat content changes in bone marrow of patients with osteoporosis can be evaluated by measuring verbebral signal decline index on chemical shift sequences of MRI which has important and high value in clinical application.
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Received: 02 April 2014
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2014, Vol. 25 
