兔急性心肌梗死后左心室重塑的MRI研究  

MRI study of left ventricular remodeling after acute myocardial infarction in rabbit model

作　　者：龚良庚[1] 夏黎明[2] 李治群[3] 黄璐[2] 庞颖[2] 任海波[1] 

机构地区：[1]南昌大学第二附属医院放射科,330006 [2]华中科技大学同济医学院附属同济医院放射科 [3]海南医学院附属医院放射科

出　　处：《中华放射学杂志》2012年第7期645-649,共5页Chinese Journal of Radiology

基　　金：国家“十一五”科技支撑计划资助项目（2007BAl05801）

摘　　要：目的观察兔急性心肌梗死（AMI）后心功能随时间演变的规律，探讨MRI影像特征及心功能指标的变化与左心室重塑的关系。方法日本长耳白兔45只，采用开胸结扎法建立心肌梗死模型。分别于术后即刻（0周）和术后1、2、4、6、8周共6个时间点行在体MR检查，测定各项心功能指标，包括：左心室舒张末期容积（EDV）、每搏输出量（SV）、射血分数（EF）、射血率峰值（PER）、充盈率峰值（PFR）。比较心肌梗死后心功能参数随时间变化的规律。在每个时间点随机取5只动物的心脏离体标本，行MR扩散张量成像（DTI），测量ADC值、各向异性分数（FA）值。不同时间点的心功能参数组间比较采用重复测量方差分析，各时间点梗死区心肌及不同区域心肌的FA值与ADC值的比较采用单因素方差分析，相邻2组均数的比较采用LSD-t检验。结果随着梗死时间的延长，左心室EDV呈现增加趋势，由术前的（2．21±0．35）ml增加到术后8周时的（3．15±0．57）ml，但差异无统计学意义（F=1．384，P=0．220）。EF则由（57．31±11．11）％下降至（34．71±8．72）％，呈明显下降趋势，差异有统计学意义（F=27．134，P=0．001）。EF随着EDV增加呈现下降趋势，线性回归分析得出一次方程：y=-5．58x＋57．7（F=8．855，P=0．005）。随梗死时间的延长，PER由（27．31±13．06）ml／s下降至（17．31±6．41）ml／s（F=2．105，P=0．037），而PFR则由（23．79±14．15）ml／s下降至（12．07±6．91）ml／s（F=2．366，P=0．011）。梗死区FA值随着梗死时间的延长而下降，由0．442±0．093下降至0．107±0．037（F=12．61，P=0．001），而ADC值则由（5．07±1．15）×10^-4mm^2／s上升至（6．39±0．78）×10^-4mm^2／s（F=4．166，P=0．022），差异均有统计学意义。梗死区、边缘区和外围区的FA值分别为0．201±0．049、0．316±0．127、0．323±0．Objective To observe the change of cardiac function after acute myocardial infarction （AMI） in rabbit model, and to study MRI characteristics of left ventricular remodeling （LVR）. Methods Forty-five Japanese white rabbits underwent chest-opening coronary artery ligation surgery to obtain rabbit myocardial infarction model. The animals were scanned on a 1.5 T MR scanner （ GE Healthcare, Chalfont St. Giles, UK） at six time-points as surgery, 1, 2, 4, 6, 8 weeks after surgery. Cardiac function parameters were measured, including left ventricular end diastolic volume （ EDV ） , stroke volume （ SV ） , ejection fraction （EF）, peak ejection rate （PER） and peak filling rate （PFR）. At each time point,5 rabbits were randomly selected and performed re-thoracotomy to obtain heart specimen. Each specimen was examined by MRI with the diffusion tensor imaging （DTI）. The value of ADC and fractional anisotrnpy （FA） were collected. Cardiac function data sets of different time points were analyzed using repeated measures data of ANOVA. The FA and ADC values of infarction myocardium set of different time points or different parts of the myocardium were analyzed using one-way ANOVA. The average was compared statistically between two adjacent groups using LSD-t test. Results Left ventricular EDV increased in progress with the time. It was increased from （2. 21±0. 35 ） ml preoperatively to （3.15±0. 57）ml 8-week postoperatively. But the difference was not statistical significant （ F = 1. 384, P = 0. 220）. EF was decreased from（57.31±11.11 ）% to （34. 71±8.72）% . It dropped significantly and the difference was statistically significant （F = 27. 134, P = O. 001 ）. EF showed a downward trend with the increase of EDV. By linear regression analysis, an equation was set up with y = - 5.58x ＋ 57.7 （ F = 8. 855 ,P = 0. 005）. On the other hand, PER showed a progressive decline from （27.31±13.06） ml/s to （ 17.31±6. 41 ） ml/s （ F = 2. 105, P = 0. 037）, and PFR de

关 键 词：心肌梗死 心室重构 磁共振成像 扩散 

分 类 号：R542.22[医药卫生—心血管疾病]