磁共振水-脂分离成像对使用糖皮质激素类风湿患者骨量评价的研究

The study of bone mass evaluation of rheumatoid patients treated with glucocorticoid with magnetic resonance water-lipid separation imaging

目的通过利用磁共振水-脂分离成像技术对使用糖皮质激素的类风湿患者椎体脂肪含量的测定,来评估不同年龄段类风湿患者随着激素应用时间的延长,椎体脂肪含量的变化,从而间接评估椎体骨质量。方法纳入40例类风湿患者为研究对象,按年龄分为30~40岁组20例、40~50岁组20例,不同年龄组在治疗前DXA行骨密度值(BMD值)与MR所测腰椎脂肪分数(FF)进行相关性分析;并对不同年龄组治疗前、激素治疗3个月后及6个月后腰椎椎体脂肪分数进行比较;骨髓脂肪FF计算公式:FF=[Mfat/(Mfat+Mwater)]*100%,式中Mwater、Mfat分别指水像及脂像ROI总像素信号强度值。结果不同年龄组类风湿患者治疗前BMD均值组间比较差异有统计学意义(P=0.007);所有患者椎体BMD值与FF值呈显著相关性;用药3个月后脂肪分数上升的程度明显高于用药6个月组,且40~50岁年龄组脂肪分数增加的程度要高于30~40岁年龄组。结论长期使用激素治疗的类风湿患者椎体内脂肪分数明显增加;发病年龄较大及用药时间长的患者腰椎脂肪分数呈逐渐上升趋势,提示使用激素治疗的类风湿患者椎体脂肪含量增加,椎体骨量下降,易发生骨质疏松性骨折。

Objective To measure the fat content of rheumatoid patients in glucocorticoid treatment using magnetic resonance water-lipid separation imaging method,to evaluate the change of fat content in the vertebrae in rheumatoid patients with different age and different hormone use time,thus indirectly evaluating the bone mass of the vertebrae. Methods 40 patients with rheumatoid diseases were enrolled in this study. They were divided into 30-40 years old group and 40-50 years old group,with20 cases each group. The correlation between DXA bone density value（ BMD） and the fat fraction（ FF） of the lumbar vertebrae was analyzed in different age groups before treatment. The fat mass of the lumbar vertebrae in different age groups was compared before treatment,3 months after hormone therapy,and 6 months later. Bone marrow fat FF calculation formula： FF =[Mfat/（ Mfat＋ Mwater） ]＊ 100%,Mwater and Mfat refered to water image and lipid like ROI total pixel signal strength value,respectively.Results The mean BMD of the patients with rheumatoid arthritis in different age groups was significantly different before treatment（ P = 0. 007）. BMD of the vertebral body was significantly correlated with FF value in all age groups. The increase of fat fraction was significantly higher after 3 months of treatment than that in 6-month groups,and the increase of fat fraction in 40-50 age group was higher than that in 30-40 age group. Conclusion Long-term use of hormones in rheumatoid patients significantly increases the vertebral body fat fraction. The lumbar fat fraction shows a gradual upward trend in patients with older age and medication for a long time,suggesting that hormone therapy increases body fat,reduces bone mass,and is prone to osteoporotic fractures in rheumatoid patients with glucocorticoid treatment.