摘要
目的探讨3.0 T MRI水-脂成像动态评估原发性骨质疏松鼠模型骨髓脂肪含量的可行性。方法 18只12周龄雌性SD大鼠随机分为假手术组(SHAM)及去卵巢组(OVX),每组9只。分别在基线(0周)、6、12周行MRI水-脂分离成像及骨密度(BMD)扫描,获取骨髓脂肪分数(FF)及BMD值。第12周时行ELISA测定血清17β雌二醇及骨转换标记物(BALP及CTX-Ⅰ)。评价两次扫描FF测量的可重复性及不同观察者的一致性。结果两次MRI扫描FF值变异系数为2.95%。两位独立观察者测量FF值,组内相关系数为0.928(95%CI为0.841~0.967,P〈0.001)。第6、12周时,OVX组FF较基线时分别增高40.0%、69.4%(P值均〈0.001)。第6周始组间FF差异有统计学意义,而组间BMD至第12周时差异有统计学意义(P值均〈0.001)。OVX组血清17β雌二醇降低67.2%,且BALP及CTX-Ⅰ标记物均较SHAM组增高,呈高转换型。结论大鼠去势12周骨质疏松模型可建立,MRI水-脂成像可动态评估骨髓脂肪含量。
Objective To investigate the feasibility of using 3.0 Tesla MRI chemical shift-based water-fat separation technique to assess marrow-fat content in postmenopausal osteoporosis models of ovariectomized rats.Methods Nineteen12-week-old female Sprague-Dawley rats were randomly and equally divided into sham-operated(SHAM) group(n=6)and ovariectomized(OVX) group(n=6).Bone mineral density(BMD) and marrow fat fraction(FF) were dynamically measured each time at the week of 0,6,and 12.At the end of experiment,serum concentration of 17β-estradiol and bonespecific alkaline phosphatase(BALP),C-terminal telopeptides of type I collagen(CTX-Ⅰ) were measured by ELISA.Rats were scanned twice to evaluate the reproducibility of FF measurement.The reliability of FF measurement was assessed with the intraclass correlation coefficient(ICC).Results OVX rats exhibited a marked increase in FF,with an increased FF variation(+ 40.0%) at week 6 from baseline,and it was maintained until week 12(+ 69.4%,P 0.001 for all).In comparison with SHAM group,FF in OVX group was dramatically elevated at week 6 but a reduction in BMD was first detected at week 12(P 0.001 for all).The OVX rats had 67.2% higher serum 17β-estradiol and higher serum BALP as well as CTX-Ⅰ compared to the SHAM rats(P 0.001 for all).Conclusion Osteoporosis can be successfully induced in rats by ovariectomy in 12 weeks.MRI chemical shift-based water-fat separation imaging may be a useful technique for dynamically evaluation of marrow fat content.
出处
《临床放射学杂志》
CSCD
北大核心
2014年第10期1604-1609,共6页
Journal of Clinical Radiology
基金
国家自然科学基金资助项目(编号:81202809
81373856)
关键词
骨质疏松
骨密度
磁共振成像
水-脂分离
Osteoporosis Bone mineral density Magnetic resonance imaging Water-fat separation