基于磁共振mDIXON-Quant技术对健康受试者股骨近端骨髓脂肪定量研究

Quantitative assessment of bone marrow fat fraction of proximal femur in healthy subjects based on MRI mDIXON‐Quant technique

目的采用MRI魔镜成像(mDIXON-Quant)技术测得骨髓质子密度脂肪分数(proton density fat fraction,PDFF)值,观测健康受试者股骨近端骨髓脂肪含量的变化趋势,并探讨年龄、性别及体质量指数(body mass index,BMI)对骨髓脂肪含量的影响。材料与方法2021年6月至2022年3月期间前瞻性招募年龄20~80岁的健康受试者,进行股骨近端常规MRI及mDIXON-Quant序列检查,符合纳入标准且图像质量满意的共227例,年龄(53.59±14.20)岁,所有受试者分为中青年组(20~60岁)和老年组(61~80岁)。分别测量股骨头、股骨颈、大转子及转子间的PDFF值,采用Mann-Whitney U检验分别比较不同年龄段、性别间骨髓PDFF值的差异性,采用Kruskal-Wallis检验进行不同分区骨髓PDFF值的比较,采用Spearman检验观察年龄、性别、BMI与骨髓PDFF值的相关性,最后将股骨近端各分区PDFF值与年龄、性别及BMI进行多元线性回归分析。结果中青年组受试者骨髓PDFF值低于老年组受试者,各分区PDFF值与年龄呈正相关(P<0.05)。男性各分区骨髓PDFF值均显著高于女性(P<0.05)。各分区间骨髓PDFF值差异具有统计学意义(P<0.05),其中大转子的骨髓PDFF值最高,股骨颈PDFF值最低。结论股骨近端骨髓脂肪含量随年龄的增长呈上升趋势,男性股骨近端骨髓脂肪含量可能高于女性,股骨近端不同分区骨髓脂肪含量不同。

Objective:The proton density fat fraction(PDFF)of bone marrow was obtained by MRI mDIXON‐Quant sequence.The change trend of bone marrow fat content in the proximal femur of healthy subjects was observed,and the effects of age,gender and body mass index(BMI)on bone marrow fat content were detected.Materials and Methods:From June 2021 to March 2022,a total of 227 patients aged 20-80 years were recruited for routine MRI examination and mDIXON-Quant examination of the proximal femur.The inclusion criteria and the image quality were satisfactory,with age of(53.59±14.20)years.The PDFF values of femoral head,femoral neck,greater trochanter and intertrochanter were obtained.Mann-Whitney U test was used to compare the difference of bone marrow PDFF values in different age groups and genders,and Kruskal-Wallis test was used to compare the bone marrow PDFF values in different regions.The Spearman correlation test was used to analyze correlations between age,gender,BMI and bone marrow PDFF,respectively.Finally,multiple linear regression analysis was performed on the PDFF values of each region of proximal femur with age,gender and BMI.Results:The PDFF value of bone marrow in young and middle-aged subjects was lower than that in old subjects,and the PDFF value of each subregion was positively correlated with age(P<0.05).The bone marrow PDFF of males was higher than that of females in all of subregions(P<0.05).There were significant differences in PDFF between the subregions(P<0.05).The bone marrow PDFF of the greater trochanter was the highest.The femoral neck PDFF was the lowest.Conclusions:The bone marrow fat content in proximal femur increased with age.The amount of bone marrow fat content in the proximal femur may be higher in men than in women.The content of bone marrow fat was different between subregions of proximal femur.