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目的:探究1.5T磁共振定量正常人左室心肌T1值、心肌细胞外容积(ECV)和心肌收缩峰值应力的正常值及其性别和节段差异.方法:共纳入46名健康志愿者行1.5T MR心脏增强检查,通过运动自动校正反转恢复(MOLLI)序列分别获取基底段、中间段和心尖段T1mapping,输入红细胞比容软件自动计算相应层面ECV mapping.分别勾画16段心肌感兴趣区并记录增强前、后T1值和ECV;将心脏电影导入后处理软件行组织追踪应力分析,半自动计算整体和节段左室收缩峰值径向应力(Err)、周向应力(Ecc)和纵向应力(Ell).结果:左室总体平均增强前T1值、增强后T1值和ECV值分别为(1 009.4±24.8)ms、(468.4±30.9)ms、(24.8±2.5)％.其中,女性增强前T1值和ECV值均高于男性[T1值:(1 020.2±20.8)ms∶(999.5±24.3) ms;ECV值:(26.5±1.9)％∶(23.1±1.8)％;均P＜0.01];心尖段ECV值(26.2±3.1)％均高于基底段(24.2±2.4)％和中间段(24.5±2.7)％(P＜0.01);增强前T1值与年龄呈正相关(r=0.371,P＜0.01);增强前T1值和ECV与心肌质量呈负相关(r值分别为-0.301、-0.585,均P＜0.05).左室总体收缩峰值径向应力(Err)、周向应力(Ecc)和纵向应力(Ell)分别为(43.2±9.9)％、(-19.8±2.3)％、(-17.5±2.2)％.其中,女性整体Ecc值和Ell值均高于男性[Ecc值:(-20.9±2.2)％∶(-18.9±2.1)％;Ell值:(-18.6±2.1)％∶(-16.5±1.7)％;均P＜0.01];Err值在心尖段较高,而Ecc和Ell值中间段较高(P值均＜0.01);Err值与年龄呈正相关(r=0.304,P＜0.05).结论:正常人左室心肌增强前T1值、ECV、Err、Ecc和Ell值存在性别以及节段差异.增强前T1值与年龄呈正相关,与心肌质量呈负相关,Err值与年龄呈正相关.“,”Objective:To investigate the normal value and gender and segmental differences of T1 value,extracellular volume and systolic peak strain of the left ventricular myocardium in normal subjects with 1.5 T magnetic resonance.Method:We recruited 46 healthy subjects without any history of cardiovascular disease to undergo contrast-enhanced cardiac magnetic resonance imaging on a 1.5T MR scanner.T1 mapping was acquired at basal,mid and apical segments before and 15 min after administration of gadolinium using a modified Look-Locker inversion recovery (MOLLI) sequence.Based on the hematocrit value of subjects,ECV mapping on the same level was automatically performed.The native and post T1 and ECV values were calculated in 16 regions of interest in left ventricle according to AHA 16 segments model.Myocardial stress analysis based on the tissue tracking technology was performed after cardiac cine data were imported into the post-processing software.And then we semi-automatically measured global and regional peak systolic radial,circumferential and longitudinal strain of the left ventricular myocardium.Result:The mean native and post T1 and ECV values of the left ventricular myocardium were (1 009.4±24.8)ms,(468.4±30.9)ms and (24.8±2.5)％.The T1 and ECV values in females were higher than males [T1:(1 020.2±20.8)ms vs.(999.5±24.3)ms,P＜0.01;ECV:(26.5±1.9)％ vs.(23.1±1.8)％,P ＜0.01].The apical segment had a significantly higher ECV than either middle or basal one [(26.2±3.1)％,(24.2±2.4) ％ and (24.5±2.7)％;P＜0.01].The native T1 value was associated with age (r=0.371,P＜0.01) and left ventricular mass (r=-0.301,P＜0.05).And the ECV was related to left ventricular mass (r=-0.585,P＜0.01).In addition,the peak systolic radial,circumferential and longitudinal strain of the left ventricular myocardium were (43.2±9.9)％,(-19.8±2.3)％ and (-17.5±2.2)％.The global Ecc and Ell values in females were greater than males [Ecc:(-20.9±2.2)％ vs.(-18.9±2.1)％,P＜0.01;Ell:(-18.6±2.1) ％ vs.(-16.5±1.7) ％,P＜0.01].The Err values in apical segment and Ecc and Ell values in middle segment were higher than other segments (P＜0.01).And the Err value correlated with age (r=0.304,P＜0.05).Conelusion:Segment and gender variation of the left ventricle in native T1,ECV,Err,Ecc and Ell value are observed.The native T1 is associated with age and myocardial mass.And the Err value is correlated with age.