心肌梗死%心室重构%磁共振成像,扩散
心肌梗死%心室重構%磁共振成像,擴散
심기경사%심실중구%자공진성상,확산
Myocardial infarction% Ventricular remodeling% Diffusion magnetic resonance imaging
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)×10-4 mm2/s上升至(6.39±0.78)×10-4 mm2/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 ±0.117,ADC值分别为(6.19±1.78)×10-4、(5.44±2.63)×10-4、(5.29±2.02)×10-4 mm2/s,差异均有统计学意义(F=3.896,P =0.004;F =3.248,P=0.018).FA、ADC值在梗死区与边缘区比较差异均有统计学意义(t=7.327,P=0.001:t =3.292,P=0.005),而边缘区和外围区的FA值、ADC值的差异无统计学意义(t=1.024,P=0.129;t=1.467,P=0.164).结论 MR心功能测定可以动态监测AMI后心室功能性重塑过程,通过DTI可以反映心室结构性重塑过程的心肌微观察结构的改变.MRI可以作为心肌梗死后左心室重塑的一种可行性的评价方法.
目的 觀察兔急性心肌梗死( AMI)後心功能隨時間縯變的規律,探討MRI影像特徵及心功能指標的變化與左心室重塑的關繫.方法 日本長耳白兔45隻,採用開胸結扎法建立心肌梗死模型.分彆于術後即刻(0週)和術後1、2、4、6、8週共6箇時間點行在體MR檢查,測定各項心功能指標,包括:左心室舒張末期容積(EDV)、每搏輸齣量(Sv)、射血分數(EF)、射血率峰值(PER)、充盈率峰值(PFR).比較心肌梗死後心功能參數隨時間變化的規律.在每箇時間點隨機取5隻動物的心髒離體標本,行MR擴散張量成像(DTI),測量ADC值、各嚮異性分數(FA)值.不同時間點的心功能參數組間比較採用重複測量方差分析,各時間點梗死區心肌及不同區域心肌的FA值與ADC值的比較採用單因素方差分析,相鄰2組均數的比較採用LSD-t檢驗.結果 隨著梗死時間的延長,左心室EDV呈現增加趨勢,由術前的(2.21±0.35) ml增加到術後8週時的(3.15±0.57)ml,但差異無統計學意義(F=1.384,P =0.220).EF則由(57.31±11.11)％下降至(34.71±8.72)％,呈明顯下降趨勢,差異有統計學意義(F =27.134,P=0.001).EF隨著EDV增加呈現下降趨勢,線性迴歸分析得齣一次方程:y=- 5.58x± 57.7 (F=8.855,P=0.005).隨梗死時間的延長,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則由(23.79±14.15) ml/s下降至(12.07±6.91) ml/s (F =2.366,P=0.011).梗死區FA值隨著梗死時間的延長而下降,由0.442±0.093下降至0.107±0.037(F=12.61,P=0.001),而ADC值則由(5.07±1.15)×10-4 mm2/s上升至(6.39±0.78)×10-4 mm2/s(F=4.166,P=0.022),差異均有統計學意義.梗死區、邊緣區和外圍區的FA值分彆為0.201±0.049、0.316±0.127、0.323 ±0.117,ADC值分彆為(6.19±1.78)×10-4、(5.44±2.63)×10-4、(5.29±2.02)×10-4 mm2/s,差異均有統計學意義(F=3.896,P =0.004;F =3.248,P=0.018).FA、ADC值在梗死區與邊緣區比較差異均有統計學意義(t=7.327,P=0.001:t =3.292,P=0.005),而邊緣區和外圍區的FA值、ADC值的差異無統計學意義(t=1.024,P=0.129;t=1.467,P=0.164).結論 MR心功能測定可以動態鑑測AMI後心室功能性重塑過程,通過DTI可以反映心室結構性重塑過程的心肌微觀察結構的改變.MRI可以作為心肌梗死後左心室重塑的一種可行性的評價方法.
목적 관찰토급성심기경사( AMI)후심공능수시간연변적규률,탐토MRI영상특정급심공능지표적변화여좌심실중소적관계.방법 일본장이백토45지,채용개흉결찰법건립심기경사모형.분별우술후즉각(0주)화술후1、2、4、6、8주공6개시간점행재체MR검사,측정각항심공능지표,포괄:좌심실서장말기용적(EDV)、매박수출량(Sv)、사혈분수(EF)、사혈솔봉치(PER)、충영솔봉치(PFR).비교심기경사후심공능삼수수시간변화적규률.재매개시간점수궤취5지동물적심장리체표본,행MR확산장량성상(DTI),측량ADC치、각향이성분수(FA)치.불동시간점적심공능삼수조간비교채용중복측량방차분석,각시간점경사구심기급불동구역심기적FA치여ADC치적비교채용단인소방차분석,상린2조균수적비교채용LSD-t검험.결과 수착경사시간적연장,좌심실EDV정현증가추세,유술전적(2.21±0.35) ml증가도술후8주시적(3.15±0.57)ml,단차이무통계학의의(F=1.384,P =0.220).EF칙유(57.31±11.11)％하강지(34.71±8.72)％,정명현하강추세,차이유통계학의의(F =27.134,P=0.001).EF수착EDV증가정현하강추세,선성회귀분석득출일차방정:y=- 5.58x± 57.7 (F=8.855,P=0.005).수경사시간적연장,PER유(27.31±13.06) ml/s하강지(17.31±6.41) ml/s (F=2.105,P=0.037),이PFR칙유(23.79±14.15) ml/s하강지(12.07±6.91) ml/s (F =2.366,P=0.011).경사구FA치수착경사시간적연장이하강,유0.442±0.093하강지0.107±0.037(F=12.61,P=0.001),이ADC치칙유(5.07±1.15)×10-4 mm2/s상승지(6.39±0.78)×10-4 mm2/s(F=4.166,P=0.022),차이균유통계학의의.경사구、변연구화외위구적FA치분별위0.201±0.049、0.316±0.127、0.323 ±0.117,ADC치분별위(6.19±1.78)×10-4、(5.44±2.63)×10-4、(5.29±2.02)×10-4 mm2/s,차이균유통계학의의(F=3.896,P =0.004;F =3.248,P=0.018).FA、ADC치재경사구여변연구비교차이균유통계학의의(t=7.327,P=0.001:t =3.292,P=0.005),이변연구화외위구적FA치、ADC치적차이무통계학의의(t=1.024,P=0.129;t=1.467,P=0.164).결론 MR심공능측정가이동태감측AMI후심실공능성중소과정,통과DTI가이반영심실결구성중소과정적심기미관찰결구적개변.MRI가이작위심기경사후좌심실중소적일충가행성적평개방법.
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 firing 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 anisotropy (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 =0.001 ).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 decreased from ( 23.79 ± 14.15 ) ml/s to ( 12.07 ± 6.91 ) ml/s ( F =2.366,P =0.011 ).FA value decreased from 0.442 ±0.093 to 0.107 ±0.037( F =12.61,P =0.001 ),and ADC valueshowed upward trend from (5.07 ± 1.15) ×10-4 mm2/s to(6.39 ±0.78) ×10-4 mm2/s (F=4.166,P =0.022 ).FA values of infarct,adjacent and remote region were 0.201 ± 0.049,0.316 ± 0.127 and 0.323 ± 0.117 respectively( F =3.896,P =0.004 ),and the ADC values in these regions were (6.19 ± 1.78 ) ×10 -4,(5.44 ± 2.63 ) × 1 0 -4,(5.29 ± 2.02 ) × 10 -4 mm2/s respectively ( F =3.248,P =0.018 ).FA and ADC values were significantly different between the infarct region and adjacent region ( t =7.327,P =0.001 ;t =3.292,P =0.005,respectively),but there was no significantly different between adjacent region and remote region ( t =1.024,P =0.129 ; t =1.467,P =0.164,respectively ).Conclusions MRI measurement of parameters of cardiac function can be used to monitor the process of left ventricular function remodeling after AMI.The process of micro-structural remodeling of myocardium can be reflected by DTI.MRI provides a feasible imaging modality for LVR after AMI.
