磁共振评估心肌梗死再灌注后心肌内出血的研究进展

急性心肌梗死是危害人类健康的重大公共卫生问题,虽然血管再通术可明显降低急性心肌梗死患者的院内死亡发生率,但部分患者存在心肌微血管的灌注障碍,影响患者的远期预后。严重的微血管功能障碍可引起毛细血管内皮细胞连接破坏,红细胞漏出血管外,导致心肌内出血,后者可进一步加重心肌细胞的损伤,使心肌梗死面积扩大,并可预测左室不良重构及远期心血管事件的发生。心血管磁共振可利用红细胞裂解产生的含铁代谢物对局部心肌组织产生的顺磁性效应,实现对心肌内出血的在体评估。该文就磁共振评估心肌梗死再灌注后心肌内出血的研究进展进行综述。     

急性缺血再灌注心肌磁共振成像实验研究

目的：通过MR灌注成保评价急性梗死心肌组织血流灌注特点。方法：采用结扎左前降支90min存灌注的方法建立为存灌注梗死心肌组，对6只犬行MRI灌注成保及延迟扫描，观察犬心肌缺血存灌注模型梗死心肌MRI特点。结果：犬心肌缺血存灌注梗死心肌MR灌注成保表现为灌注缺损区，延迟扫描表现为高信号。结论：MR灌注成保有助于评价心肌血流，诊断心肌缺血存灌注梗死心肌。     

急性心肌梗死MR心肌灌注成像实验及临床应用研究

目的采用MR首过灌注成像评价急性心肌梗死心肌组织血流灌注特点及治疗效果。方法急性心肌梗死模型犬9条,对照组犬4条;心肌梗死患者16例,正常对照组8例。采用磁化准备梯度回波（turboFLASH）序列行MR首过灌注及延迟成像扫描,绘制左心室各壁心肌信号强度-时间曲线,分析病变心肌信号强度-时间曲线特点。结果心肌梗死模型犬及未溶栓治疗组心肌首过呈低强化,延迟扫描信号强度高于正常心肌,曲线上升时间、上升斜率、峰值时间和对比增强率明显低于正常心肌。心肌梗死溶栓再灌注组首过及延迟均强化,延迟扫描时病变心肌信号强度高于正常心肌,信号强度-时间曲线仅曲线上升时间延长。心肌梗死模型犬和未溶栓治疗组病变心肌峰值信号强度较正常心肌明显降低,分别为正常心肌的(44.8±13.0)%和(54.5±12.0)%,溶栓再灌注组病变心肌峰值信号强度可达正常心肌的(90.8±13.0)%。结论turboFLASHMR心肌首过灌注成像有助于评价心肌血流灌注及溶栓疗效。     

急性心肌梗死再灌注治疗前后心肌血流和代谢的变化及临床意义

目的　探讨急性心肌梗死患者行经皮冠状动脉腔内成形术 (PTCA)和支架术后心肌血流、脂肪酸代谢及糖代谢的变化及其临床意义。方法　 2 2例急性心肌梗死患者 ,于发病后 4周行延迟PTCA ,术前 (急性期 )及术后 (慢性期 )分别行2 0 1 Tl、1 2 3I β 甲基碘苯脂十五烷酸 (BMIPP)SPECT显像及1 8F 脱氧葡萄糖 (FDG)PET心肌显像。将左心室分成 13个节段 ,采用 4级评分法对2 0 1 Tl、1 2 3I BMIPP显像放射性分布进行视觉评价 ,两者得分差为2 0 1 Tl BMIPP不匹配。在血流减低部位 ,定量测定1 8F FDG摄取。慢性期复查冠状动脉造影。结果　急性期心肌血流 脂肪酸代谢不匹配的节段 ,1 8F FDG摄取率明显高于匹配节段 [(76 .5± 10 .6 ) %和 (4 5 .8± 8.6 ) % ,P <0 .0 1],慢性期两者无明显差异。冠状动脉非再狭窄患者其慢性期2 0 1 Tl BMIPP不匹配 (0 .2 5± 0 .4 2 )及1 8F FDG摄取率 [(5 2 .1± 8.1) % ]较急性期 [0 .36± 0 .5 1和 (72 .8± 9.8) % ]明显降低 (P均 <0 .0 1) ;冠状动脉再狭窄患者其慢性期与急性期比较 ,2 0 1 Tl BMIPP不匹配及1 8F FDG摄取率无明显变化。结论　观察急性心肌梗死PTCA前后心肌血流 脂肪酸代谢及糖代谢的变化 ,可间接预测PTCA后再狭窄。     

13N-NH3心肌灌注显像评价兔心肌梗死模型缺血再灌注

目的　探讨兔心肌梗死模型缺血再灌注与梗死面积之间的关系。方法　完全闭塞 16只雄性新西兰大白兔冠状动脉左前降支 4 5min ,随机分为再灌注组 (n =8)和无再灌注组 (n =8) ,7～10d后行1 3N NH3PET CT心肌灌注显像 ,与三氯四氮唑 (TTC)染色梗死灶缺损百分比进行比较。HE染色评价梗死灶病理学改变。结果　TTC染色示无再灌注组、再灌注组实际梗死灶缺损百分比分别为 (2 5 7± 2 3) %、(2 1 5± 2 4 ) % (P =0 0 0 31)。1 3N NH3PET CT心肌灌注显像示 ,无再灌注组与再灌注组缺损百分比分别为 (2 4 6± 2 2 ) %和 (2 0 5± 2 5 ) % (P =0 0 0 37)。组内TTC染色与PET CT显像结果差异无显著性 (P >0 0 5 )。结论　1 3N NH3PET CT心肌灌注显像较TTC染色能更准确测定心肌梗死灶范围。     

急性心肌梗死后心肌再灌注的MRI实验研究

急性心肌梗死后心肌再灌注的ＭＲＩ实验研究苏宏冯晓源沈天真陈君坤陈星荣随着心血管介入放射学的迅速进展，急性心肌梗死（ＡＭＩ）后血流再灌注成功率明显提高，其对于降低ＡＭＩ死亡率起到了重要作用［１］。准确判定ＡＭＩ溶栓治疗后有无血流再灌注，对评价临床疗效及...     

双核素心肌断层显像对急性心肌梗塞再灌注疗效的评价

目的：对比评价急性心肌梗塞（ＡＭＩ）的各种再灌注治疗对缺血性心肌挽救的疗效。材料和方法：３５例ＡＭＩ患者被分为接受静脉内组织纤溶酶原激活剂的ＩＶＴ组,接受急症经皮冠脉成形术的ＰＴＣＡ和ＩＶＴ＋ＰＴＣＡ组。用碘１２３标记的β甲基碘苯十五烷酸（１２３ＩＢＭＩＰＰ）和铊２０１（２０１Ｔｌ）双核素心肌断层显像分别评价心肌的缺血范围及梗塞面积,并计算出心肌挽救指数（ＳＩ）。结果：虽然三组间缺血范围无显著差别,但ＰＴＣＡ组的梗塞面积却明显大于ＩＶＴ和ＩＶＴ＋ＰＴＣＡ组。因而,ＩＶＴ和ＩＶＴ＋ＰＴＣＡ组的ＳＩ显著大于ＰＴＣＡ组。结论：ＩＶＴ＋ＰＴＣＡ是治疗ＡＭＩ的理想方案之一。     

犬急性心肌梗死磁共振心肌灌注及电影成像实验研究

目的　采用MR快速序列研究急性心肌梗死的首过灌注特点及心功能改变。材料与方法　犬心肌梗死模型 9只 ,均进行T1WI磁化准备梯度回波序列 (TurboFLASH)首过灌注扫描及MR电影成像 (cine MR) ,完成检查后处死 ,分析心肌首过灌注特点及局部心功能变化 ,并与病理检查比较。结果　首过灌注时梗死心肌表现为灌注缺损 ,信号强度 时间曲线上升延缓 ,曲线斜率和峰值信号强度分别为 0 .0 2 5± 0 .0 2 0和 0 .84± 0 .2 7,较正常心肌(0 .13± 0 .0 80和 2 .0 2± 0 .99,P <0 .0 0 0 1)明显下降 ,峰值时间和曲线上升时间分别为 37.78± 11.90s和 32 .70±14 .0 9s,较正常心肌 (17.14± 6 .0 6s和 14 .2 8± 5 .14s,P <0 .0 0 0 1)明显延长。延迟期正常心肌信号强度下降 ,而梗死心肌仍呈上升趋势。首过灌注中灌注缺损面积与TTC染色一致。梗死节段室壁运动及室壁厚度异常。结论　MR首过灌注成像可反映病变心肌组织血流灌注信息 ,cine MR能测定节段室壁功能。结合首过灌注和心功能分析 ,可对梗死心肌在形态学和功能学两方面进行定性、定量分析 ,有助于评价梗死心肌活力     

心肌声学造影估测冠脉血流储备及心内膜下心肌灌注的实？…

目的探讨心肌声学造影定量冠脉血流储备及心内膜下心肌灌注的意义。材料与方法13只开胸犬左旋支临界狭窄状态及静脉注射潘生丁后分别进行心肌声学造影并与放射性微球所测心肌血流量对比。结果静注潘生丁后,正常对照区心肌血流量及心肌造影曲线下面积、峰值强度、最大上升斜率指标均明显增加;而临界狭窄缺血区无明显变化。在临界狭窄缺血区,放射性微球所测的心内膜下／心外膜下心肌血流比率减低;但以造影曲线下面积指标所测则无明显变化。结论心肌声学造影曲线下面积、峰值强度及最大上升斜率是定量评价冠脉血流储备的可靠指标;在当前情况下心肌声学造影技术尚不能用于评价心内膜下心肌灌注。     

双核素显像对直接经皮冠脉治疗后再灌注心肌的评价

临床发现,直接经皮冠脉治疗(PCI)术后,TIMI 3级的患者,仍有1/4～1/3的病例心功能和预后没有得到改善.近年来,配备了超高能准直器的双探头SPECT可同时探测低、高能核素,可以无创、快捷而又准确地观察PCI后心肌的灌注及代谢变化[1～3].     

Teboroxime is a marker of reperfusion after myocardial infarction

Background  

It has been shown that serial teboroxime imaging can rapidly assess coronary perfusion in viable myocardial distributions. However, the myocardial uptake of teboroxime after reperfusion of acutely infarcted myocardium has not been critically evaluated. The study object was to assess whether teboroxime uptake in acutely infarcted myocardium is linearly related to blood flow.     

Prediction of myocardial recovery by dobutamine magnetic resonance imaging and delayed enhancement early after reperfused acute myocardial infarction

The purpose was to study dobutamine magnetic resonance cine imaging (DOB-MRI) and delayed myocardial contrast enhancement (DE) early after reperfused acute myocardial infarction (AMI) for the predicion of segmental myocardial recovery and to find the optimal dose of dobutamine. Fifty patients (56±12 years, 42 males) with reperfused AMI underwent DOB-MRI and DE studies 3.5 (1–19) days after reperfusion. In DOB-MRI systolic wall thickening (SWT) was measured in 18 segments at rest and during dobutamine at 5, 10 and 20 μg*kg⁻¹*min⁻¹. Dysfunctional segments were identified and the extent of DE was measured for each segment. Segmental recovery was examined after 8 (5–15) months. Two hundred-forty-eight segments were dysfunctional with presence of DE in 193. DOB-MRI showed the best prediction of recovery at 10 μg*kg⁻¹*min⁻¹ of dobutamine with sensitivity of 67%, specificity of 63% and accuracy of 66% using a cut-off value for SWT of 2.0 mm. DE revealed a sensitivity of 68%, specificity of 65% and accuracy of 67% using a cut-off value of 46%. Combined analysis of DOB-MRI and DE did not improve diagnostic performance. Early prediction of segmental myocardial recovery after AMI is possible with DOB-MRI and DE. No improvement is achieved by dobutamine >10 μg*kg⁻¹*min⁻¹ or a combination of DOB-MRI and DE.     

Prognostic value of adenosine Tl-201 myocardial perfusion imaging after acute myocardial infarction: Results of a prospective clinical trial

BACKGROUND: We have previously shown in retrospective studies that adenosine myocardial perfusion imaging (MPI) done after acute myocardial infarction (AMI) can effectively predict the risk of future cardiac events in these patients. The objective of this study was to validate these observations in a prospective clinical trial. METHODS AND RESULTS: One hundred twenty-six stable patients underwent quantitative adenosine MPI at a mean of 4.5 +/- 2.9 days after AMI. On the basis of the MPI results, they were divided into 3 risk groups: low risk (< 20% perfusion defect), intermediate risk (> or = 20% perfusion defect with < 10% ischemia), and high risk (> or = 20% perfusion defect with > 10% ischemia). The patients were followed up for 11 +/- 5 months for the occurrence of cardiac events: death, myocardial infarction, unstable angina, or congestive heart failure. The actual event rates correlated very well with the prespecified risk groups (19% for the low-risk group, 28% for the intermediate-risk group, and 78% for the high-risk group; P < .001). The significant multivariate predictors for events were female gender (relative risk [RR], 2.90; P = .002), left ventricular ejection fraction (RR, 1.34; P = .04), and ischemic defect size (RR, 1.46; P = .001), with a global chi2 value of 26.7. CONCLUSION: This study demonstrates, in a prospectively designed clinical trial, that quantitative adenosine MPI performed soon after AMI can effectively predict the risk of future cardiac events. These findings are currently being validated in an ongoing, large, multicenter, international clinical trial.     

Transplantation of progenitor cells after reperfused acute myocardial infarction: evaluation of perfusion and myocardial viability with FDG-PET and thallium SPECT

Clinical outcome after myocardial infarction depends on the extent of irreversibly damaged myocardium. Implantation of bone marrow-/circulating blood-derived progenitor cells has been shown to improve contractile cardiac function after myocardial infarction in both experimental and initial clinical studies. In the present study, first observations of the effect of local intracoronary progenitor cell infusion on the regeneration of infarcted cardiac tissue after acute myocardial infarction was evaluated by means of ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) and ²⁰¹Tl single-photon emission computed tomography (SPECT). Twenty-six patients underwent intracoronary infusion of bone marrow-derived (BMCs) (15 patients) or circulating blood-derived endothelial progenitor cells (EPCs) (11 patients) 4±2 days after acute myocardial infarction. Based on a left ventricular segmentation model (17 segments), mean signal intensities as a parameter of viability and perfusion in the infarct zone and non-infarct areas were calculated quantitatively by PET and SPECT at baseline and at 4 months of follow-up. Transplantation of progenitor cells was associated with a significant increase in the mean signal intensity (MSI) in the infarct zone from 54.5% (25th and 75th percentiles: 47.7%, 60.0%) to 58.0% (52.7%, 66.7%) on PET (P=0.013) and from 58.0% (49.5%, 63.0%) to 61.5% (52.5%, 70.2%) on SPECT (P=0.005). Global left ventricular ejection fraction (LVEF) increased from 53.5% (42.6%, 60.0%) to 58.0% (53.0%, 65.8%) (P<0.001). In the five patients without an increase in MSI on PET, LVEF changed from 60.0% (50.0%, 64.0%) to 72.0% (64.0%, 75.5%) at follow-up. PET and SPECT did not show any significant changes in MSI in the non-infarct areas [from 73% (68.5%, 76.2%) to 73% (69.7%, 78.0%) for PET and from 72.0% (66.5%, 77.6%) to 73.0% (67.5%, 78.2%) for SPECT]. There were no significant differences in myocardial viability and perfusion between BMC and EPC infusion. These preliminary results show that coronary stenting and transplantation of progenitor cells result in a significant increase in myocardial viability and perfusion. Therapeutic effects can be reliably measured by PET and SPECT.     

Patterns of myocardial perfusion in the acute and chronic stage after myocardial infarction: a cardiac magnetic resonance study

Objectives

The aim of the present study was to monitor the microvascular perfusion damage in the acute and chronic stage after myocardial infarction (MI) using first-pass dynamic magnetic resonance imaging (MRI). Furthermore we compared improvement of myocardial microcirculation and function in infarcted and non-infarcted left midventricular segments over a 4 months period.

Materials and methods

Cardiac magnetic resonance imaging (CMR) was performed in 46 consecutive patients within 8 days after successful reperfused first acute ST-elevation MI and 4 months thereafter. First-pass images were obtained by using Turbo-FLASH sequence during a bolus injection of Gd-based contrast agent. Signal-intensity-to-time (SIT) curves of 276 left ventricular myocardial segments were generated. Furthermore, infarct volumes as well as parameters of regional left ventricular function of corresponding segments were calculated.

Results

SIT curves highly significantly correlate with MI size (r = −0.57, r = −0.43 respectively; all p < 0.0001) as well as with segmental wall thickening (SWT) of corresponding segments at baseline and follow-up scans (r = 0.20, r = 0.15 respectively; all p < 0.02). SWT differ highly significantly between segments with and those without LE at baseline (p < 0.003) and follow-up examinations (p < 0.008), presenting either clear improvements at follow-up (all p < 0.0001). In contrast, infarcted segments showing microvascular obstruction evidenced neither significant recovery of SIT nor of SWT (p = NS).

Conclusion

Our data indicate a close relationship between MI size and myocardial perfusion as well as function. Beyond epicardial artery patency, the assessment of quantitative parameters of myocardial perfusion and contractile function with the help of CMR appears to be a useful tool for estimating myocardial recovery after acute MI.     

甘丙素在急性心肌梗塞发病中的临床意义

测定31例急性心肌梗塞(AMI)患者血浆甘丙素(GAL)的放免活性,结果提示AMI患者急性期各次血浆GAL水平明显高于对照组.伴高血压、糖尿病和心功能不全者升高更显著.GAL和内皮素(ET)、血糖水平均呈正相关.实验性心肌梗塞大鼠血浆GAL、血清肌酸激酶(CK).CK同功酶(CK-MB)、丙二醛(MDA)含量亦明显高于对照大鼠.用GAL抗血清治疗心梗大鼠,减少坏死面积45.4%和缩小了梗塞范围47.1%,血浆GAL水平明显降低,血清CK、CK-MB、MDA活性有所抑制,提示早期阻断GAL的生物学效应,对防治AMI有重要意义.实验还发现牛磺酸对GAL亦有拮抗效用,显示牛磺酸有心肌细胞保护作用.     

不同年龄急性ST段抬高型心肌梗死患者再灌注时间延迟分析

目的分析不同年龄急性ST段抬高型心肌梗死(STEMI)患者的再灌注延迟时间分布,探讨不同年龄组之间的差异。方法选取2011年7月至2015年10月急诊收治并符合入选标准的STEMI患者309例,根据年龄分为3组,年龄≥75岁组(n=32)、60~74岁组(n=118)与年龄≤59岁组(n=159),分析各急救时间分布,包括发病至首次医疗接触时间(SO-to-FMC)、转运时间、首次医疗接触到再灌注(FMC-to-B)、导管室启动延迟时间、介入操作延迟时间、急诊至球囊扩张血管再通时间(D-to-B),并观察其临床预后。结果年龄≥75岁组患者合并高血压病、多支病变者及高Killip分级者比例较高;与年龄≤59岁组比较,年龄≥75岁组STEMI患者30 d和1年内的死亡率和总主要不良心脑血管事件(MACCE)发生率均明显增高,差异有统计学意义(P<0.05);年龄≥75岁组与年龄≤59岁组比较,在转运延迟时间上增加,差异有统计学意义(P<0.05),其余各项指标差异均无统计学意义(P>0.05)。结论年龄≥75岁高龄患者合并症多、临床预后差,年龄因素可能是影响院前延迟的重要原因。     

急性心肌梗死药物溶栓后早期介入治疗

目的　直接经皮冠状动脉腔内成形术 (PTCA)为急性心肌梗死 (AMI)提供了积极的有效的又安全的恢复心肌灌注的手段 ,优于常规溶栓治疗 ,但直接PTCA仍有时间延误问题。本研究旨在探讨AMI患者在等待PTCA时间延误期内 ,使用常规治疗剂量短效溶栓剂 (rt PA)治疗 ,促使梗死相关动脉(IRA)早期开通的有效性 ,及溶栓后立即进行加速PTCA可行性和安全性。方法　 75例AMI患者用阿司匹林和肝素后接受rt PA 2 0mg 1次团注 ,随后 80mg半小时内快速滴入 ,尽快行急诊冠状动脉造影术 ,对IRA行PTCA或支架植入术 ,如果血管开通 ,仍有残余狭窄 ,亦行PTCA及支架术 ,和同期进行 88例AMI直接PTCA进行对比分析。本试验终点包括 ,到达导管室血管开通率 ,PTCA的结果 ,治疗后导管室血管开通率 ,PTCA的结果 ,治疗后 2周内左室功能及不良事件发生率。结果　到达导管室时 ,联合治疗 (溶栓加PTCA)血管开通率 88% (2 6 %TIMIⅡ级 ,6 2 %TIMIⅢ级血流 ) ,直接PTCA组为 36 % (2 0 %为TIMIⅡ级血流 ,16 %TIMIⅢ级血流 ) (P <0 .0 0 1)两组PTCA血流再通率相似 ,分别为 96 %、94 %。对IRA恢复TIMIⅢ级血流效果相同 ,分别为 84 % ,82 %。 2周内左室功能 (超声法EF)联合治疗组优于PTCA组(6 5 .4 % ,5 4 .6 % ,P <0 .0 5 )两组住院期间不良事件发生     

Early detection of the no-reflow phenomenon in reperfused acute myocardial infarction using technetium-99m tetrofosmin imaging

Evaluation of myocardial perfusion in the early stage of acute myocardial infarction (MI) is clinically important for adjunctive therapies to minimize infarct size. To determine the role of early scintigraphic detection of impaired myocardial reperfusion after primary coronary angioplasty (PTCA) in patients with acute MI, semiquantitative technetium-99m tetrofosmin single-photon emission tomographic (SPET) imaging was performed before primary PTCA (before; area at risk), 60 min after PTCA (after) and at 1 month (1 M; final infarct) in 35 patients with acute MI. The left ventricle was divided into 13 segments and the defect score was calculated as the sum of the perfusion defect of each segment, from 3 (complete defect) to 0 (normal perfusion). A significant myocardial perfusion change after PTCA was defined as a change in the defect score (before minus after PTCA) of ≥4. The echocardiographic asynergic score was defined as the number of asynergic (severe hypokinetic or akinetic) segments corresponding to the analogous segments on SPET images, and recovery of wall motion was calculated as absolute change in the asynergic score (before PTCA minus 1 M). Among the 35 patients, 15 (43%) had a change in the defect score of <4 (no reflow: group 1) while 20 had a change in the defect score of ≥4 (reflow: group 2). There were no significant differences between the two groups with respect to the time between admission to PTCA, revascularization time, collateral grade or Thrombolysis in Myocardial Infarction (TIMI) flow grade before PTCA. Despite the lack of a difference in area at risk between the two groups (group 1 = 12.8±4.3 and group 2 = 15.1±4.7), final infarct size in group 1 was significantly larger compared with that in group 2 (8.1±4.3 vs 4.9±3.0, P<0.001). Recovery of wall motion was significantly smaller in group 1 than in group 2 (4.3±1.7 to 3.5±1.5 vs 4.1±2.1 to 1.6±1.6, P<0.001). In conclusion, a small change (<4) in defect score (scintigraphic no-reflow phenomenon) after primary PTCA indicates persisting impaired myocardial perfusion or irreversible cellular damage just after PTCA which is associated with poor recovery of wall motion, as compared with that observed in cases of reflow (≥4 in defect score). Received 12 September and in revised form 11 November 1998     

急性心肌梗死患者心率变异性临床分析

对８４例急性心肌梗死患者进行心率变异性分析。应用２４ｈ磁带记录器。进行２４ｈＨｏｌｔｅｒ心电图记录，对记录磁带采用电子计算机分析，对急性心肌梗死的病变范围和程度及预后进行估计。