正常肾脏的磁共振扩散峰度成像研究

目的:验证肾脏扩散峰度成像(DKI)的可行性,并明确年龄因素对肾脏水分子扩散特性是否存在影响。方法:用3.0T磁共振扫描仪对年龄范围在20-60岁之间的41名健康志愿者进行磁共振DKI扫描。按年龄因素分四组(20-29岁)、(30-39岁)、(40-49岁)、(50-59岁),行t-test及方差分析及比较不同年龄因素对肾皮质和髓质的分数各向异性(FA)值、平均扩散(MD)值、峰度各向异性(FAK)值、平均峰度(MK)值的影响并进行统计学分析。结果:正常肾皮质的FA值、FAK值、MK值(0.327±0.047,0.325±0.088,0.688±0.087)显著低于髓质(0.389±0.062,0.396±0.091,0.802±0.124);而正常肾皮质MD值(1.633±0.157)显著高于髓质(1.588±0.162)。不同年龄段之间的FA、MD、FAK、MK值均无统计学差异(P0.05);左、右肾之间的比较无统计学差异(P0.05)。结论:正常肾脏DKI良好的揭示了肾皮质与髓质的水分子扩散特性;年龄因素对肾脏水分子扩散特性没有影响。

Study of MR Diffusion Kurtosis Imaging of Normal Kidneys

ABSTRACT Objective: To assess the feasibility of diffusion kurtosis imaging (DKI) of normal kidneys, and to report whether the influence of age factor exists to the water diffusion characteristics of kidney. Methods: Forty-one healthy volunteers aging from twenty to sixty underwent diffusion kurtosis imaging (DKI) scans with a 3.0T MR scanner. According to ages, they were divided into four groups: 20-29 years, 30-39 years, 40-49 years, and 50-59 years old. The effect of age factor on fractional anisotropy (FA) value, fractional anisotropy of kurtosis (FAK) value, mean diffusivity (MD) value and mean kurtosis (MK) value of medullary and cortical were measured and analyzed. Results: The FA value, FAK value and MK value of normal renal cortex (0.327±0.047, 0.325±0.088, 0.688±0.087) were significantly lower than the medulla (0.389±0.062, 0.396±0.091, 0.802±0.124). The normal MD value of cortex (1.633±0.157) was significantly higher than the medulla (1.588±0.162). No statistical significance of renal FA, MD, FAK and MK values was found between different age groups (P>0.05). No statistical significance of each value was found between the left and right kidney (P>0.05). Conclusion: DKI of normal kidney shows good water diffusion properties of the renal cortex and medulla. The age factor has no impact on the values of FA, MD, FAK and MK.