心脏磁共振量化指标在心肌活性评价中的应用

目的探讨心脏磁共振(CMR)的量化指标在心肌梗死后存活心肌评价中的应用价值。方法收集临床资料完整的有心肌梗死病史的冠心病患者29例,行CMR检查,获取相关影像学数据。运用磁共振后处理工作站,观察评估心室壁的运动情况及室壁心肌灌注的信号特征;测定心肌延迟强化区与邻近正常心肌区域首过灌注时间、首过灌注最大上升斜率及心肌延迟强化信号值;同时分析心肌梗死透壁程度与室壁运动情况间的关系。结果所有患者均出现至少1个节段的延迟强化,29例患者共计493个心肌节段被评价,有32个节段出现延迟强化。延迟强化区首过灌注时间较正常心肌区域长[(4.45±1.20)vs(3.60±2.0),P=0.005],首过灌注最大上升率小[(27.70±15.70)vs(39.63±18.21),P=0.000],病变区延迟强化的信号值较正常心肌区域高[(69.81±34.15)vs(21.67±13.26),P=0.015]。一元线性回归分析显示,心肌延迟强化程度与其运动能力呈负相关(r=-0.467,P<0.05)。心室壁内延迟强化灶越大,运动能力越差:即存在3分或透壁性延迟强化灶的心室壁运动能力为2级或3级;非透壁延迟强化灶<50%的心室壁运动能力为0级或1级。结论 CMR的cine-MR,FP-MPI及DE-MRI的量化指标均可用于心肌活性评价,只有综合运用各种扫描技术才能准确评估存活心肌的情况。     

对比心肌灌注显像与心脏磁共振延迟增强成像在原发性扩张型心肌病中的诊断价值

目的：对比MPI（心肌灌注显像）与DE-MRI（心脏磁共振延迟增强成像）在原发性扩张型心肌病中的诊断价值。方法回顾性分析该院2012年5月—2014年9月收治的80例原发性扩张型心肌病患者的临床资料,均接受DE-MRI及MPI,间隔时间＜7 d。DE-MRI显现无延迟、内膜下延迟、透壁性延迟、壁间延迟强化,而MPI显现放射性弥漫性及放射性节段性缺损或减低,对两样本率行X2检验。结果（1）MPI及DE-MRI结果：80例患者行MPI,其中38例(47.50％)心肌呈放射性分布状,伴有弥漫性减低情况,DE-MRI延迟强化发生率为26.32％(10/38);42例(52.50％)呈节段性缺损或减低状,DE-MRI延迟强化发生率为85.71％(36/42),两组DE-MRI延迟强化发生率比较差异具有统计学意义（P＜0.05）;（2）DE-MRI分型。结果立足于心肌节段角度,将36例延迟强化及节段性放射性异常者划分为A（灌注正常）、B（灌注减低）、C（灌注缺失）三组,在DE-MRI分型组成上,A组（112：35：2：5）与B组（98：23：7：1）及C 组（13：0：5：5）比较差异具有统计学意义（P＜0.05）。结论行DE-MRI者的MPI特征多表现为放射性节段性及放射性弥漫性减低,前者DE-MRI易显现延迟强化情况,临床上应引起足够重视。     

MR电影判断急性心肌梗死后存活心肌的价值

目的:探讨MR电影心肌运动影像判断急性心肌梗死后存活心肌的价值。方法:分析22例急性心肌梗死患者(急性梗死组)和20例正常对照组的MR电影,判断MR电影对急性心肌梗死后存活心肌检测率。结果:正常对照组心肌各室壁厚度变化一致(P>0.05),梗死心肌节段室壁厚度变化明显小于正常心肌(P<0.05)。室壁厚度变化减小(<2mm)对梗死心肌节段的检测敏感性为77%,特异性为100%;结合首过及延迟灌注异常可将其敏感性提高到91%。结论:MR电影心肌运动影像是MRI诊断急性心肌梗死后存活心肌可靠的指标,可初步判断心肌存活性,行靶区首过心肌灌注可以明显提高检查的敏感性。     

Evaluation of Myocardial Viability after Myocardial Infarction with Intravenous Real-time Myocardial Contrast Echocardiography

The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Viable myocardium was defined by evident improvement of segmental wall motion 3 months after coronary revascularization. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification; partial or reduced opaciflcation or subendocardial contrast defect; contrast defect. The former two conditions were used as the standard to define the viable myocardium. The results showed that 109 abnormal wall motion segments were detected among 18 patients with myocardial infarction, including 47 segments of hypokinesis, 56 segments of akinesis and 6 segments of dyskinesis. The wall motion of 2 segments with hypokinesis before coronary revascularization which showed homogeneous opacification, 14 of 24 segments with hypokinese and 20 of 24 segments with akinese before coronary revascularization which showed partial or reduced opaciflcation or subendocardial contrast defect was improved 3 months after coronary revascularization. In our study, the sensitivity and specificity of evaluation of myocardial viability after myocardial infarction by intravenous real-time myocardial contrast echocardiography were 94.7% and 78.9%, respectively. It was concluded that intravenous real-time myocardial contrast echocardiography could accurately evaluate myocardial viability after myocardial infarction.     

磁共振心肌灌注成像评价心肌梗死PTCA治疗前后心肌存活

目的 评价磁共振心肌灌注成像(MRMPI) 检测心肌梗死存活心肌的作用. 方法 选择心肌梗死患者51 例.采用1.5 T MR扫描仪,反转恢复快速小角度激励( IR-turbo FLASH) 序列,全部患者均在静脉注射钆喷替酸葡甲胺(Gd-DTPA) 0.1 mmol/kg、MRMPI 首过期及5~30 min 延迟期成像.21 例行静息、负荷99锝单光子发射计算机体层摄影术( single photon emission computed tomography, SPECT) 进行对照研究.首过期行短轴面成像,延迟期行短轴面及长轴面成像.结果 51例心肌梗死患者,42 例(82.3%) 首过期显示灌注减低;50 例(98%) 延迟增强.在21例168个心肌段SPECT诊断无活性心肌段48个,MRMPI 示梗死区均有延迟增强,SPECT诊断存活心肌段120 个,MRMPI 示97段无延迟增强.以静息、负荷99m锝SPECT 作为参考标准,MRMPI 的敏感度、特异度分别为100%、80.8%. 结论 MRMPI 可有效地检测心肌梗死的存活和非存活心肌,以及其程度和范围.     

MRI心肌延迟增强扫描在心肌梗死诊断中的初步应用

目的 初步评价MRI心肌延迟强化在诊断心肌梗死中的价值.方法 2005～2006年对本院9例确诊为心肌梗死的患者,8例疑诊患者进行MRI多技术扫描.结果 9例确诊患者MRI延迟增强扫描心肌都有不同程度强化.8例疑诊患者中2例心内膜下心肌梗死,2例心肌缺血,1例肥厚型心肌病伴多灶性心肌坏死,1例广泛心肌损害,2例心肌显示正常.结论 MRI心肌延迟增强扫描对冠心病急慢性心肌梗死坏死心肌诊断是准确和可靠的.     

硝酸甘油介入心肌核素显像检测存活心肌的意义

目的探讨急性心肌梗死(AMI)与陈旧性心肌梗死(OMI)心肌存活状态的差异。方法应用SPECT对63例Q波MI患者行常规99mTc-MIBI心肌显像(静息显像),隔日舌下含服NTG(1.0mg)后5分钟静注99mTc-MIBI,再行心肌显像(介入显像),其中4例患者行冠脉搭桥术(CABG),3例于CABG术后3月再行心肌显像。结果静息显像中239个节段灌注异常,NTG介入后有97个节段得到不同程度的改善,改善率为40.59%,静息显像平均得分为9.65±4.31,介入显像平均得分为7.75±4.66,两者比较差别有统计学意义(P<0.001)。3例CABG术前检测有改善的6个节段,术后均得到不同程度的改善。AMI组与OMI组1月-6月组,6月-3年组相比较,存活心肌的检出率分别为43.10%,42.80%,35.15%,虽呈逐渐下降,但无统计学意义(P>0.05)。结论NTG介入99mTc-MIBI心肌显像可明显提高存活心肌的检出率,且该方法简便易行,安全可靠。OMI患者亦有存活心肌,也可从血运重建中获益。     

磁共振心肌灌注检测猪急性心肌梗死的实验研究

目的:探讨磁共振心肌灌注成像技术在检测猪急性心肌梗死后心肌活性中的作用。方法:猪心肌梗死模型13只,均进行快速梯度回波序列(FGREET)首过灌注扫描及反转恢复梯度回波序列(MDE)延迟时相扫描。扫描后处死,分析心肌首过灌注和延迟时相特点,并与病理检查结果进行对照。结果:9只首过灌注时梗死心肌表现为灌注减低,其信号强度显著低于周围心肌,12只延迟期梗死心肌表现为延迟强化,而正常心肌信号强度下降,低于梗死心肌。结论:MR心肌灌注成像可有效检测急性心肌梗死后的梗死心肌。     

Comparison of two visual angiographic perfusion grades in acute myocardial infarction

Introduction. Prognosis after opening the obstructed coronary artery in acute myocardial infarction (AMI) is influenced by several factors. In routine clinical practice, revascularization is considered to be successful when the restoration of epicardial blood-flow is complete. However, the patent epicardial artery does not always provide functional recovery in the myocardium. There are two visual angiographic grades to assess myocardial perfusion: myocardial blush grade (MBG) and TIMI myocardial perfusion grade (TMP). The aim of our study was to compare these two parameters, how they correlate with short-term indicators of myocardial damage.

Patients and methods. The two visual grades were assessed along with enzymatic infarct size as creatine kinase release (CK), echocardiographic left ventricular ejection fraction (LVEF), and ST-segment resolution (STR) in 62 patients with acute myocardial infarction and successful revascularization.

Results. Better correlation was found with TMP in case of all clinical parameters (CK: R= ? 0.687, P<0.001; LVEF: R=0.586, P<0.001; STR: R=0.574, P<0.001). MBG also showed significant correlations with clinical measurements, except for enzymatic infarct size (CK: R=? 0.062, P=0.626; LVEF: R=0.389, P=0.002; STR: R=0.348, P=0.006).

Conclusion. Our findings suggest that the clearance of the dye (described by TMP) is more characteristic to myocardial recovery after AMI, than maximal contrast density (described by MBG) in the clinical practice.     

Factors affecting thrombolysis in myocardial infarction myocardial perfusion frame count: insights of myocardial tissue-level reperfusion from a novel index for assessing myocardial perfusion

Background  Myocardial tissue-level perfusion failure is associated with adverse outcomes following ST-elevation myocardial infarction (STEMI) despite successful epicardial recanalization. We have developed a new quantitative index—thrombolysis in myocardial infarction (TIMI) myocardial perfusion frame count (TMPFC)—for assessing myocardial tissue level perfusion. However, factors affecting this novel index of myocardial perfusion are currently unknown.

Methods  A total of 255 consecutive STEMI patients undergoing primary angioplasty were enrolled. Myocardial tissue level perfusion was assessed by TMPFC, which measures the filling and clearance of contrast in the myocardium using cine-angiographic frame counting. We differentiate three groups with two cut off values for TMPFC: a TMPFC of 90 frames was the upper boundary of the 95% confidence interval (CI) for the TMPFC observed in normal arteries, and a TMPFC of 130 was the 75th percentile of TMPFC.

Results  STEMI patients with TMPFC >130 frames (68 patients, 26.7%) had higher clinical and angiographic risk factor profiles as well as a higher 30-day MACE rate compared with those with TMPFC ≤90 frames and those with TMPFC >90 and ≤130 frames. Multivariable analysis identified that the independent predictors of TMPFC >130 frames were age ≥75 years (OR 2.08, 95% CI 1.21 to 3.58, P=0.007), diabetes (OR 1.37, 95% CI 1.01 to 1.86, P=0.042), Killip class ≥2 (OR 1.52, 95% CI 1.05 to 2.21, P=0.027), and prolonged pain-to-balloon time (OR 1.73, 95% CI 1.07 to 2.79, P=0.013). TMPFC >130 frames was identified as the strongest independent predictor of 30-day major adverse cardiac event (MACE) (OR 2.77, 95% CI 1.21 to 6.31, P=0.008), along with age ≥75 years (OR 2.19, 95% CI 1.11 to 4.33, P=0.016), female gender (OR 1.67, 95% CI 1.03 to 2.70, P=0.038), and Killip class ≥2 (OR 1.83, 95% CI 1.07 to 3.14, P=0.021).

Conclusions  STEMI patients with poor myocardial perfusion assessed by TMPFC had higher risk factor profiles. Advanced age, diabetes, higher Killip class, and longer ischemia time were independent predictors of impaired TMPFC after primary percutaneous coronary intervention. These results emphasize that particular attention should be paid on myocardial microvascular reperfusion in STEMI patients with these risk factors.

     

实验性犬急性心肌梗塞早期MRI诊断研究

目的 :探讨 MRI对急性心肌梗塞早期的诊断价值。方法 :采用闭胸式方法复制犬急性心肌梗塞模型 5只 ,于术前行 MRI平扫 ,术后 1h行 MRI平扫及 Gd- DTPA增强扫描 ,观察不同时间磁共振信号强度改变。结果 :栓塞后 1h平扫 T1WI示正常心肌与梗塞区之间信号强度差异无显著性 ;T2 WI示栓塞区信号强度明显增高 ,增强后示栓塞区明显强化。结论 :MRI对急性心肌梗塞早期诊断具有重要价值。     

替罗非班不同用药剂量对急性心肌梗死再灌注及疗效的影响

目的 探讨急性ST段抬高心肌梗死(STEMI)患者行急诊直接经皮冠状动脉成形术(PCI)前应用不同用药剂量替罗非班(商品名为欣维宁)对梗死相关血管(IRA)及疗效的影响.方法 172例STEMI患者分为3组.A组(61例)术前只予基础用药,阿司匹林300 mg、氯吡格雷300 mg顿服.B组(56例)在术前基础用药上加用替罗非班300～400μg/h静脉滴注.C组(55例)在B组用药基础上再静脉注射替罗非班10μg/kg.对3组IRA自溶率、术中无复流、ST段回落＞50%、心肌灌注分级,及住院期间临床事件(心力衰竭、大出血、死亡)进行比较分析.结果 急诊冠状动脉造影发现,A、B、C组的IRA自溶率分别为31.1%、41.7%和72.7%,ST段回落＞50%构成比分别为75.4%、87.5%和94.5%,3组间的差异均有统计学意义(P值均＜0.05).术中B、C组的无复流发生率有低于A组的趋势,但差异无统计学意义(P值均＞0.05).3组在住院期间的心力衰竭、严重出血并发症、病死率的差异均无统计学意义(P值均＞0.05).结论 急诊PCI术前静脉滴注联合静脉注射替罗非班能显著减少STEMI患者的血栓负荷,明显升高患者IRA自溶率,减少术中无复流的发生.