正常肾脏弥散张量磁共振成像及与人体测量指标的相关性

Characteristics of diffusion tensor magnetic resonance imaging and correlation with body physiological measurement indexes in healthy native kidneys

目的探索成人正常肾脏弥散张量磁共振成像（DTI—MRI）特点，以及与部分人体测量指标的相关性。方法研究纳入80例行腹部磁共振检查的非肾脏病患者。DTI-MRI扫描采用单次激发自旋回波平面成像序列（SE．EPI）以及阵列空间敏感度编码技术（ASSET）。测量双侧肾脏皮髓质平均弥散率（MD），轴向弥散率（AD），辐射弥散率（RD），第1、2、3特征向量值（λ1、λ2、λ3）和各向异性分数（FA）。采集人体测量指标包括年龄、性别、身高、体质量、体质量指数（BMI）、体表面积（BSA）和估算的肾小球滤过率（eGFR）。分析DTI参数与人体测量指标的相关性。结果皮质区MD，λ2、λ3、RD值高于髓质区。皮质区FA值低于髓质区。左侧肾脏皮质区FA、λ1值和髓质区FA值高于右侧肾脏，左侧肾脏髓质沁和RD值低于右侧肾脏。女性髓质区λ2、λ3，和RD值高于男性而髓质FA值低于男性。髓质FA值（r=0．351，P=0．002）和入，值（r=0．277，P=0．018）与eGFR正相关，而髓质FA值与年龄（r=-0．250，P=0．033）负相关。结论肾脏水分子弥散特性在两侧肾脏和不同性别之间存在差异，髓质肾小管结构的规则性和小管内液弥散和灌注水平随年龄增加而改变。

Objective To explore the characteristics of diffusion tensor imaging （DTI） magnetic resonance（MR） imaging in healthy native kidneys. Methods Eighty patients without chronic kidney disease underwent DTI-MRI with spin echo-echo planar （SE-EPI） sequences and array spatial sensitivity encoding technique （ASSET）. Cortical and medullary mean diffusivity （MD）, axial and radial diffusivity （AD and RD） values and primary, secondary and tertiary eigenvalues （λ1, λ2, λ3） and fractional anisotropy （FA） were analyzed in both kidneys and in different genders. Physiological indexes including age, gender, height, weight, body mass index （BMI）, body surface area （BSA）, and estimated glomeiular filtration rate （eGFR） were recorded. Correlations between DTI parameters and physiological indexes were analyzed. Results Cortical MD, λ2, λ3, RD values were higher than corresponding medullary values except for λ1 value. Cortical FA value was lower than medullary FA value. Cortical FA, λ1 values and medullary FA were higher in left kidney than in right kidney. Medullary λ3 and RD values were lower in left kidney than in fight kidney. Medullary λ2,λ3 and RD values were higher and medullary FA values were lower in female than in maie. Medullary FA （r = 0.351, P = 0.002） and λ1 （r= 0.277, P= 0.018） positively correlated with eGFR and medullary FA （r=-0.250, P= 0.033）negatively correlated with age. Conclusions Renal water molecular diffusion differences exist in human bilateral kidneys and different genders. Renal medullary tubular regularity, tubular diffusion and perfusion correlate with age.