骨髓成分变化对健康成年人腰椎骨髓扩散信号及表观扩散系数的影响

Influence of bone marrow composition of lumbar spine on bone marrow diffusion signal intensity and ADC values in healthy adults

目的分析骨髓成分变化对健康成年人腰椎骨髓扩散信号及表观扩散系数(ADC)的影响。方法分析140例健康成年人上腹部磁共振图像,其中男69例,女71例。在两点法水脂分离图像上,测量L_(1)椎体骨髓脂肪分数。在扩散加权成像(b=800s/mm^(2))上,根据L_(1)椎体骨髓与邻近竖脊肌信号强度比值,计算腰椎肌肉标准化扩散信号值(mnDWI);并测量L_(1)椎体ADC值。根据骨髓脂肪分数分为低、中、高脂肪含量三组,比较不同性别腰椎mnDWI及ADC值的差异,并分析男性、女性腰椎骨髓成分与腰椎mnDWI、ADC值间的相关性。结果在低、中、高脂肪含量组中,女性腰椎mnDWI高于男性(P<0.05)。低脂肪含量组中,女性腰椎ADC值高于男性(P<0.01);而在中、高脂肪含量组中,男性和女性腰椎ADC值差异无统计学意义(P>0.05)。男性、女性腰椎mnDWI与脂肪分数呈负相关(r_(s)=-0.36、-0.55,P<0.01)。女性腰椎ADC值与骨髓脂肪分数呈负相关(r_(s)=-0.63,P<0.01)。结论骨髓成分变化对健康成年人腰椎mnDWI及ADC值有一定的影响,且存在一定的性别差异。

Objective To analyze the influence of marrow composition on the bone marrow diffusion signal intensity and apparent diffusion coefficient(ADC)values of the lumbar spine in healthy adults.Methods The upper abdominal magnetic resonance imaging was analyzed in 140 healthy adults,of whom 69cases were male and 71cases were female.The fat fraction of bone marrow in the lumbar 1vertebra was measured using a two-point water-lipid separation method.The muscle-normalized signal intensity of bone marrow on DWI(mnDWI)(b=800s/mm^(2))of the lumbar 1vertebra was calculated by comparing their signal intensity with that of the adjacent erector spinae muscles.Additionally,the ADC values of the lumbar 1vertebra were measured.The mnDWI and ADC values of lumbar 1vertebra were compared between male and female in low-,medium-,and highfat content groups categorized by fat fraction.The correlation of bone marrow composition with mnDWI and ADC values of the lumbar 1vertebra was analyzed for both male and female.Results The mnDWI of the lumbar 1vertebra was significantly higher in female than in male in the low-,medium-,and high-fat content groups(P<0.05).In the low-fat content group,the ADC values of the lumbar 1vertebra were significantly higher in female than those in male(P<0.01).However,in the medium-and high-fat content groups,the difference in ADC values between male and female was not significant(P>0.05).The mnDWI of the lumbar 1vertebra was negatively correlated with the fat fraction in both male and female(r_(s)=-0.36,-0.55,P<0.01).The negative correlation between ADC values and fat fraction of the lumbar 1vertebra was found in female(r_(s)=-0.63,P<0.01).Conclusion The composition of bone marrow influences the mnDWI and ADC values of the lumbar spine in healthy adults,which has a certain gender difference.