正常成年人臂丛神经MRI对比噪声比及扩散张量成像参数与年龄的相关性研究

Age-related study of brachial plexus MRI contrast to noise ratio and diffusion tensor imaging values in normal adults

目的探讨臂丛神经扩散张量成像(DTI)参数各向异性分数(FA)、表观扩散系数(ADC)及三维神经鞘信号增高并背景抑制弛豫增强的快速采集成像(3D SHINKEI)序列的对比噪声比(CNR)与年龄的相关性。方法前瞻性招募54名成年健康志愿者和6例格林巴利综合征患者,健康志愿者分为3个年龄组,21~40岁组(n=20)、41~60岁组(n=20)和≥61岁组(n=14)。所有受试者接受3.0 T MR扫描,包括DTI和3D SHINKEI序列。由两名医师分别独立测量双侧臂丛神经颈5~8神经根的FA和ADC值,计算平均值。于3D SHINKEI序列图像中测量臂丛神经的CNR。采用组内相关系数(ICC)评价两名医师测量FA和ADC值结果的一致性。采用单因素方差分析比较不同年龄组FA、ADC、CNR的差异。采用简单线性回归模型及Pearson相关性分析检测FA、ADC、CNR与年龄的相关性。采用独立样本t检验比较不同性别间FA、ADC值的差异。结果两名医师测量受试者的FA、ADC值一致性好,ICC值分别为0.811,0.901。21~40岁组、41~60岁组、≥61岁组的臂丛神经FA值分别为0.397±0.023、0.368±0.023、0.334±0.018,ADC值分别为(1.376±0.072)、(1.466±0.086)、(1.486±0.080)×10-3 mm2/s,FA和ADC值差异有统计学意义(F=25.311,P<0.001;F=9.948,P<0.001)。21~40岁、41~60岁、≥61岁的受试者臂丛神经CNR值分别为510.583±192.846、502.581±128.821、426.782±113.648,差异无统计学意义(F=1.429,P=0.249)。臂丛神经FA值与年龄呈高度负相关(r=-0.745,P<0.001),ADC值与年龄呈中度正相关(r=0.596,P<0.001)。臂丛神经3D SHINKEI序列CNR与年龄呈低度负相关(r=-0.292,P=0.033)。男性与女性受试者间臂丛神经FA、ADC值差异均无统计学意义(t=1.496,P=0.141;t=-1.557,P=0.126)。格林巴利综合征患者臂丛神经的FA值低于同年龄组(41~60岁)健康志愿者(t=6.129,P<0.001),ADC值无统计学差异(t=-1.335,P=0.186)。结论正常成年人臂丛神经FA、ADC值及CNR存在随年龄变化而变化的趋势,其中以FA值较为显著。

Objective To investigate the correlation of age with diffusion tensor imaging(DTI)values as fractional anisotropy(FA),apparent diffusion coefficient(ADC)and contrast to noise ratio(CNR)of three-dimensional nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation imaging(3D SHINKEI)of the brachial plexus in normal adults.Methods A total of 54 adult healthy volunteers and 6 patients with Guillain-Barre syndrome were prospectively enrolled from October 2018 to April 2019.Healthy volunteers were divided into 3 groups according to age as 21-40 years old group(n=20),41-60 years old group(n=20),and≥61 years old group(n=14).All of them underwent MRI examination of the brachial plexus,including DTI and 3D SHINKEI sequences.The average FA and ADC values of the brachial plexus were measured and calculated through the fusion of DTI and 3D SHINKEI by 2 physicians independently.The contrast to noise ratio(CNR)of brachial plexus nerve was measured in 3D SHINKEI sequence images.Intraclass correlation efficient(ICC)was used to analyze the consistency between the two physicians.A simple linear regression model and Pearson correlation analysis were used to detect the correlation between FA,ADC,CNR and age.One-way analysis of variance was used to compare the differences of FA,ADC and CNR in different age groups.The FA and ADC values in different genders were compared by independent sample t-test.Results Inter-observer agreements of the 2 physicians were good for FA and ADC values with ICC values of 0.811 and 0.901,respectively.For different groups,FA values were 0.397±0.023,0.368±0.023,and 0.334±0.018 and ADC values were(1.376±0.072)×10^-3 mm^2/s,(1.466±0.086)×10^-3 mm2/s,(1.486±0.080)×10^-3 mm2/s,for 21-40,41-60,and≥61 years old groups,respectively with statistical significant difference(F=25.311,P<0.001;F=9.948,P<0.001).The CNR of the brachial plexus were 510.583±192.846,502.581±128.821,and 426.782±113.648 for 21-40,41-60,and≥61 years old group without statistical difference(F=1.429,P=0.249).The FA value of brachial plexus was highly negatively correlated with age(r=-0.745,P<0.001),while the ADC value was moderately positively correlated with age(r=0.596,P<0.001).The CNR of 3D SHINKEI sequence was negatively correlated with age(r=-0.292,P=0.033).There was no statistically significant difference in brachial plexus FA and ADC values between male and female subjects(t=1.496,P=0.141;t=-1.557,P=0.126).The FA value of Guillain-Barre syndrome patients was lower than that of healthy volanteers in the same age group(t=6.129,P<0.001),and the ADC value had no statistical diference(t=-1.335,P=0.186).Conclusion The values of FA,ADC and CNR of brachial plexus in normal adults change with age.Among them,FA value is more significant.