正常成人前列腺外周带的磁共振扩散峰度成像年龄相关性研究

Age-Related Changes of Prostatic Peripheral Zone in Normal Adults:Evaluation by MR Diffusion Kurtosis Imaging

目的分析正常成人前列腺外周带扩散峰度成像(DKI)相关参数与年龄相关性变化趋势。方法将67名符合纳入标准的健康志愿者按年龄分成3组:A组(15~30岁,n=26),B组(31~50岁,n=20),C组(≥51岁,n=21)。对所有志愿者行MRI常规序列扫描及DKI扫描,应用扩散峰度模型分析得出平均扩散峰度(MK)、平均扩散系数(MD)及各向异性分数(FA)值。采用配对样本t检验分析前列腺外周带左、右两侧各参数之间差异;采用方差分析(ANOVA)及LSD法对各参数在不同年龄段前列腺外周带中的差异进行比较。采用Pearson相关性分析对各参数与年龄相关性进行分析。结果 MK、MD和FA值在左、右两侧前列腺外周带之间差异无统计学意义(P>0.05);3组外周带的MK值分别为0.714±0.058、0.682±0.057、0.584±0.046;MD值分别为(1.781±0.183)、(1.937±0.234)、(2.323±0.314)μm^2/ms;FA值分别为0.207±0.033、0.183±0.016、0.154±0.026,不同年龄组外周带的MK、MD和FA值差异均有统计学意义(P<0.05);Pearson相关性分析结果表明,外周带MK值与年龄呈负相关(r=-0.811,P<0.05),FA值与年龄呈负相关(r=-0.691,P<0.05),而MD值与年龄呈正相关(r=0.785,P<0.05)。结论正常成人前列腺外周带的MK、MD和FA值与年龄相关,随年龄的增长,MK、FA值呈降低趋势,而MD值呈升高趋势。

Objective To evaluate the correlation between the DKI parameters on prostatic peripheral zone（ PZ） and age in normal adults. Methods 67 volunteers who conformed to the standards were divided into three groups by age：group A（ 15 ~ 30 years,n = 26）,Group B（ 31 ~ 50 years,n = 20）,Group C（ ≥51years,n = 21）. They then underwent imaging studies of conventional MR sequences and DKI; the diffusion kurtosis model was applied to figure out the MK,MD and FA values. A paired t test was used to evaluate the difference in MK,MD and FA values between the left and right side of PZ. The difference in MK,MD and FA values of PZ between groups was determined by the one-way analysis of variance（ ANOVA） and compared by least significant difference（ LSD） algorithm. Pearson analysis was used to investigate the correlation between the MK,MD and FA values of PZ. Results The results indicated that no statistical difference was found in the MK,MD and FA values between the left and right side of PZ（ P〈0. 05）. The MK values of PZ in three groups were0. 714 ± 0. 058,0. 682 ± 0. 057 and 0. 584 ± 0. 046,respectively. The MD values were found to be 1. 781 ± 0. 183,1. 937 ±0. 234 and 2. 323 ± 0. 314,accordingly. The FA values were found to be 0. 207 ± 0. 033,0. 183 ± 0. 016 and 0. 154 ±0. 026. The MK,MD and FA values in PZ were significantly（ P〈0. 05） different between the groups. Pearson correlation analysis results showed that the MK and FA values in PZ have negative correlation with age（ r =-0. 811,P〈0. 05）,（ r=-0. 691,P〈0. 05）,while the MD values exhibited a positive correlation with age（ r = 0. 785,P〈0. 05）. Conclusion The MK,MD and FA values in the normal prostatic PZ were age-dependent. The MK and FA values were decreased with age while the MD values were increased.