存活心肌定量分析评价溶栓及PTCA急诊治疗AMI的效果

目的采用硝酸酯类药物介入心肌断层显像,用存活心肌定量分析结果评价溶栓和PTCA治疗AMI的效果.方法将35例AMI病人随机分成溶栓组和PTCA组,10天后做静态及异舒吉介入心肌断层显像,分别计算心肌缺损面积(%).治疗12周后行静态显像,并计算出缺损面积(%).结果溶栓组和PTCA组比较静态显像缺损面积(%)为32.04±17.95和29.88±15.43(P＞0.05),异舒吉介入显像缺损面积(%)为26.62±15.13和15.07±13.80(P＜0.05),存活心肌面积(%)为9.45士6.63和14.81±4.97(P＜0.05).术后12周缺损面积增加者溶栓组和PTCA组各为4例和7例.结论PTCA较溶栓治疗AMI可以得到更大面积的存活心肌,但术后12周PTCA组中病变面积又扩大的病人较溶栓组有增多趋势.     

硝酸甘油介入^99mTc—MIBI心肌显像定量测定心肌梗死面积及心肌存活的实验研究

目的为了比较犬心肌梗死(MI)模型的静息心肌显像、潘生丁介入心肌显像、硝酸甘油(NTG)介入心肌显像所测定MI面积及存活心肌与病理性MI面积.方法选择12条杂种犬建立MI模型,给予NTG1.0mg后行心肌显像.次日将犬随机分为两组一组进行常规静息显像,另一组进行潘生丁介入显像,采用靶心图测定MI面积,并与病理性MI面积进行对比研究.结果犬病理性MI面积为(17.80±3.07)%,NTG介入显像、静息显像、潘生丁介入显像测定MI面积分别为(19.98±3.16)%、(25.53±3.91)%、(31.82±2.82)%.其中NTG介入显像测定MI面积与病理性MI面积大小最为接近(P＞0.05),并有很好相关性(r=0.91).静息显像有(21.52±4.8)%、潘生丁显像有(37.80±4.5)%的梗死心肌在使用NTG后得到恢复.结论利用NTG介入显像后可以降低静息显像、潘生丁介入显像所测得的MI面积与实际MI面积的误差,并可提高两者存活心肌的检出率.     

硝酸甘油介入~(99m)Tc-MIBI心肌显像定量测定心肌梗死面积及心肌存活的实验研究

目的　为了比较犬心肌梗死 (MI)模型的静息心肌显像、潘生丁介入心肌显像、硝酸甘油 (NTG)介入心肌显像所测定MI面积及存活心肌与病理性MI面积。方法　选择 12条杂种犬建立MI模型 ,给予NTG1.0mg后行心肌显像。次日将犬随机分为两组 :一组进行常规静息显像 ,另一组进行潘生丁介入显像 ,采用靶心图测定MI面积 ,并与病理性MI面积进行对比研究。结果　犬病理性MI面积为 ( 17.80± 3 .0 7) % ,NTG介入显像、静息显像、潘生丁介入显像测定MI面积分别为 ( 19.98± 3 .16 ) %、( 2 5 .5 3± 3 .91) %、( 31.82± 2 .82 ) %。其中NTG介入显像测定MI面积与病理性MI面积大小最为接近 (P >0 .0 5 ) ,并有很好相关性 (r =0 .91)。静息显像有 ( 2 1.5 2± 4.8) %、潘生丁显像有 ( 37.80± 4.5 ) %的梗死心肌在使用NTG后得到恢复。结论　利用NTG介入显像后可以降低静息显像、潘生丁介入显像所测得的MI面积与实际MI面积的误差 ,并可提高两者存活心肌的检出率。     

核素心肌显像判断AMI后心肌存活

目的观察急性心肌梗塞(AMI)患者NTG介入实验对顿拟和冬眠心肌的影响.方法将42例AMI患者分别行硝酸甘油(NTG)介入与静息+延迟99mTc-MIBI(甲氧基异丁基异晴)心肌SPECT显像,测定患者存活心肌,以再充填率和存活分数为判断指标.结果静息心肌显像检出灌注异常节段126个,延迟显像51个节段再充填,再充填率为40.5%,NTG介入后有81个节段再充填,再充填率为64.3%,两者间差异有显著性(χ2＝8.56,P＜0.01),心肌存活分数NTG介入为0.36±0.24明显高于未介入的0.18±0.16(P＜0.05).结论 NTG显像相结合的定量方法可用于测定AMI的存活心肌,且方法简单可靠,重复性强.     

小剂量多巴酚丁胺及硝酸异山梨酯负荷超声心动图检测左心室收缩功能严重减低患者存活心肌的准确性

目的与99mTc甲氧基异丁腈(MIBI)/18FDG双核素同时采集法(DISA)SPECT心肌显像对比,评价小剂量多巴酚丁胺、硝酸异山梨酯(异舒吉)单用及合用的二维超声心动图试验检测冠心病左心室收缩功能严重减低患者存活心肌的准确性和安全性。方法40例陈旧性心肌梗死患者,左心室射血分数(39.4±5.1)%,1周内分别完成小剂量多巴酚丁胺、异舒吉单用及合用的二维超声心动图试验和DISASPECT心肌显像。比较两种方法对存活心肌的检出率、符合率和Kappa值。结果对存活心肌的检出率,DISASPECT为64.0%,多巴酚丁胺10μg·kg-1·min-1二维超声为60.1%,异舒吉多巴酚丁胺5μg·kg-1·min-1二维超声为59.1%。以DISASPECT检测结果为标准,药物负荷二维超声识别存活心肌的特异性在85.7%～96.0%,各剂量间差异均无显著性意义(P均>0.05);而识别的敏感性和符合率以多巴酚丁胺10μg·kg-1·min-1二维超声最高,分别为86.5%和86.5%(Kappa=0.71);异舒吉与多巴酚丁胺合用时,敏感性比异舒吉单用、符合率比两者单用时均显著增加(P均<0.001),以异舒吉多巴酚丁胺5μg·kg-1·min-1二维超声最高,分别为84.6%和85.1%(Kappa=0.69),与多巴酚丁胺10μg·kg-1·min-1二维超声相当,且副作用更少。结论检测冠心病左心室收缩功能严重减低患者的存活心肌,多巴酚丁胺10μg·kg-1·min-1二维超声的检出率与DISASPECT心肌显像相当,识别的敏感性和准确性好;异舒吉与小剂量多巴酚丁胺合用,能提高两药单用时的检出率、识别敏感性和准确性,特别是异舒吉多巴酚丁胺5μg·kg-1·min-1二维超声已达多巴酚丁胺10μg·kg-1·min-1单用时水平,且更安全。     

KATP通道参与介导吸入麻醉药诱导的兔在体心肌预适应

目的探讨KATP通道在吸入麻醉药异氟醚、七氟醚和地氟醚所诱导的心肌预适应中的作用.方法64只新西兰白兔随机分成8组缺血-再灌注组(IR),异氟醚预处理组(IP),七氟醚预处理组(SP),地氟醚预处理组(DP),异氟醚预处理+优降糖组(IP+G),七氟醚预处理+优降糖组(SP+G),地氟醚预处理+优降糖组(DP+G),优降糖组(G).每组均接受左冠脉前降支3小时阻断和3小时再灌注.吸入药预处理组在缺血前分别吸入1.1%异氟醚、2%七氟醚、6%地氟醚30分钟后,洗脱15分钟,加用优降糖组在吸入麻醉药前或相当时间静脉注入优降糖0.33mg/kg.结果心肌梗死面积占缺血面积的比IR组为0.61±0.11,IP、SP、DP组分别减少至0.39±0.06、0.31±0.07和0.32±0.08,与IR组相比均有显著差异(P均<0.05);IP+G、SP+G、DP+G组分别是0.64±0.12,0.57±0.12和0.62±0.11,与IR组相比均无显著差异(P均>0.05);G组并不增加梗死面积(1.17±0.32)g,梗死面积占缺血面积比为0.63±0.13,与IR组相比无显著差异(P>0.05).结论异氟醚、七氟醚、地氟醚预处理产生的心肌保护作用与激活KATP通道有关.     

99mTc-MIBI心肌显像评价犬急性心肌梗塞激光心肌血管重建术治疗的效果

目的:评价心肌灌注显像在激光心肌血管重建术(TMR)治疗急性心肌梗塞(AMI)的作用。方法:心梗犬(n=9)和心梗后即刻TMR犬(n=12)术后24小时行99mTc-MIBI心肌灌注显像,靶心图定量测定缺损分数,与术后24小时以上不同时间的TTC测定的梗塞面积与左室面积之比的比较。同时,进行心肌组织学检查和评价犬的生存率。结果:①所有犬均见左室前壁和心尖区放射性分布明显稀疏或缺损,但激光组所见的缺损范围明显较梗塞组小,心梗组缺损分数DF(0.35±0.05,n=9)高于激光处理组(0.30±0.06,n=12),P<0.05。激光组梗塞面积和左室面积比IS?蛐LV(0.07±0.05,n=11)明显小于心梗组(0.18±0.06,n=8),P<0.05。②HE染色显示心梗组(术后14~90天)均见广泛的陈旧性心梗;激光组(术后30~90天)可见心肌坏死和炎性肉芽及瘢痕形成呈灶性分布,不同时期切片还可见到开放或半开放的陈旧激光管道,伴有内皮形成,腔内和周围心肌间隙均可见较多红细胞。管道周围见丰富的新生小血管。③心梗组生存时间?眼(18.0±2.7)天?演明显短于激光处理组?眼(51.3±3.4)天?演,P<0.05。结论:TMR能有效地增加缺血心肌的血流灌注,减轻AMI后的心肌细胞损害,缩小心梗范围,提高AMI动物的生存率;99mTc-MIBI心肌灌注显像可准确评价犬AMI行TMR后的局部心肌血流灌注状况,并能预测TMR治疗效果。     

硝酸甘油介入心肌断层显像判断心梗患者存活心肌的研究

探讨含服硝酸甘油(NTG)介入~(99m)Tc—甲氧基异丁基异晴(MIBI)心肌断层显像在评价心梗患者心肌存活中的价值。方法:37例心梗患者中病程≤4周的急性心梗(AMI)者18例,病程>4周的陈旧心梗(OMI)者19例。所有患者先行静息心肌断层显像,24～48小时后再行NTG介入心肌断层显像。结果:18例AMI患者静态心肌显像112个节段异常,NTG介入后有32个节段改善或明显改善,总改善率28.6％,无变化和恶化率71.4％;19例OMI患者静态心肌显像87个节段异常,NTG介入后有45个节段改善或明显改善,总改善率51.7％,无变化和恶化率48.3％。结论:AMI组和OMI组NTG介入后心肌灌注总改善率有明显差异(P<0.05)。NTG介入心肌显像对陈旧心梗患者心肌存活的判定具有一定的价值,但对AMI者应注意结果受临床用药的影响。     

利声显心肌声学造影显像在冠脉搭桥术中的应用

目的　评价经静脉注射利声显心肌声学造影间隙显像在冠脉搭桥术中的应用价值。方法　用经静脉注射利声显心肌声学造影间隙显像,对25例临床诊断为陈旧性心肌梗死准备行冠脉搭桥术患者手术前后的心肌灌注和心脏功能进行分析。结果　术前灌注正常、减弱和无灌注的节段分别为22、57和13个。术后灌注正常、减弱和无灌注的节段分别为55、35和2个。造影记分指数从术前的0.74±0.08增加到术后的0.89±0.06,差别有极显著性意义（P<0.001）。92个与搭桥相关的节段中,术后59个（64%）功能改善。室壁运动记分指数从术前的1.50±0.27减少到术后1.24±0.20（P<0.001）。左室射血分数从0.49±0.05增加到0.55±0.04（P<0.001）。手术前后室壁运动记分指数和左室射血分数的变化程度与心肌声学造影检测为存活心肌的节段数高度相关（r=0.96,0.82,P均<0.001）;术后室壁运动记分指数和左室射血分数与术前心肌造影记分指数相关（r=-0.64,0.60,P均<0.05）。心肌声学造影对冠脉搭桥术后心脏节段功能恢复的预测敏感性和特异性分别为98%和36%。结论　经静脉注射利声显心肌声学造影不仅可用于评价冠脉搭桥术的效果,还可预测术后左室功能的恢复。     

心脉通胶囊对急性心肌缺血大鼠心肌cNOS mRNA表达的影响

目的探讨心脉通胶囊对实验性大鼠急性心肌缺血的预防效果及与一氧化氮(NO)的相关机制.方法应用垂体后叶素致大鼠急性心肌缺血模型,测定其心室肌组织一氧化氮合酶(cNOS)mRNA的表达,结果用积分光密度(IOD)表示.结果急性心肌缺血组大鼠心室肌组织cNOSmRNA的表达为20.8±4.1,明显低于正常对照组56.5±12.0,差异非常显著(P<0.01);心肌缺血前使用心脉通胶囊组的心室肌组织cNOSmRNA的表达为38.2±8.0,高于急性心肌缺血组(P<0.05),但仍低于正常对照组(P<0.05).结论心脉通胶囊可能通过提高心室肌组织表达cNOSmRNA,进而使NO产生增加,达到改善心肌缺血的作用.     

Technetium-99m-labelled HL91 and technetium-99m-labelled MIBI SPECT imaging for the detection of ischaemic viable myocardium: a preliminary study

Purpose: The assessment of myocardial viability has become an important aspect of the diagnostic and prognostic work‐up of patients with coronary artery disease. Technetium‐99m labelled sestamibi (^99mTc‐MIBI) myocardial perfusion imaging may underestimate the viability of ischaemic myocardium. Technetium‐99m labelled 4,9‐diaza‐3,3,10,10‐tetramethyldodecan‐2,11‐dione dioxime (^99mTc‐HL91) is a hypoxia‐avid agent which can identify acutely ischaemic viable myocardium in a canine model using a standard gamma camera. The aim of this study was to evaluate uptake character of ischaemic viable myocardium and diagnostic performance of single‐photon emission computed tomography (SPECT) imaging by ^99mTc‐HL91 and ^99mTc‐MIBI in detecting ischaemic viable myocardium in coronary heart disease. Methods: A total of 41 patients with coronary artery disease were recruited from March 2008 to May 2009. For detecting ischaemic viable myocardium, SPECT imaging by ^99mTc‐HL91 and ^99mTc‐MIBI were performed in all patients before coronary revascularization. Six patients with single ischaemic myocardial segment received a 2‐day SEPCT/CT imaging protocol and the uptake of ^99mTc‐HL91 in ischaemic myocardium was quantitatively analysed. The remaining 35 patients received a 1‐day ^99mTc‐HL91 and ^99mTc‐MIBI SPECT imaging protocol. Resting ^99mTc‐MIBI myocardial perfusion imaging in 3–18 months after revascularization was used as the standard methodology to evaluate the myocardial viability. Results: In 41 patients, 66 ischaemic myocardial segments were proven to be viable and 12 to be necrotic by resting ^99mTc‐MIBI myocardial perfusion imaging after coronary revascularization. Furthermore, 60 viable segments with negative uptake of ^99mTc‐MIBI showed positive uptake of ^99mTc‐HL91. The remaining six viable segments and 12 necrotic segments showed both negative uptake of ^99mTc‐HL91 and ^99mTc‐MIBI. The sensitivity, specificity, accuracy, Younden Index, positive predictive value and negative predictive value for evaluating ischaemic viable myocardium were 90·9%, 100%, 92·3%, 90·9%, 100% and 66·7%, respectively. Ischaemic viable myocardium had the negative ^99mTc‐MIBI uptake and positive ^99mTc‐HL91 uptake, which demonstrated a mismatched uptake character. Quantitative analysis indicated the uptake of ^99mTc‐HL91 in viable myocardium was increasing in the first 1–3 h and remained stable at the 3–4 h after injection. Conclusion: Functional SPECT imaging with ^99mTc‐HL91 and ^99mTc‐MIBI can be used to detect the seriously ischaemic but viable myocardium with a mismatched uptake character. The uptake of ^99mTc‐HL91 in the viable myocardium reached a stable level at 3–4 h after injection.     

Imaging Techniques in Nuclear Cardiology for the Assessment of Myocardial Viability

The assessment of myocardial viability has become an important aspect of the diagnostic and prognostic work-up of patients with ischemic cardiomyopathy. Although revascularization may be considered in patients with sufficient viable myocardium, patients with predominantly scar tissue should be treated medically. Patients with left ventricular dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischemia but at the same time benefit most from revascularization. It is important to identify viable myocardium in these patients, and radionuclide myocardial scintigraphy is an excellent tool for this. Single-photon emission computed tomography perfusion scintigraphy (SPECT), whether using ²⁰¹thallium, ^99mTc-sestamibi, or ^99mTc-tetrofosmin, in stress and/or rest protocols, has consistently been shown to be an effective modality for identifying myocardial viability and guiding appropriate management. Metabolic and perfusion imaging with positron emission tomography (PET) radiotracers frequently adds additional information and is a powerful tool for predicting which patients will have an improved outcome from revascularization. New techniques in the nuclear cardiology field, like attenuation corrected SPECT, dual isotope simultaneous acquisition (DISA) SPECT and gated FDG PET are promising and will further improve the detection of myocardial viability. Also the combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and non-invasive coronary angiography to myocardial perfusion imaging and quantification. Evaluation of the clinical role of these creative new possibilities warrants investigation.     

Myocardial reperfusion in thrombolysis A 99Tcm-Sestamibi SPECT study in patients with acute myocardial infarction

Summary. This study presents the outcome of myocardial scintigraphy performed before and after thrombolytic treatment in 16 patients with acute myocardial infarction using ⁹⁹Tc^m-Sestamibi (Cardiolite®, Du Pont Scandinavia AB, Kista, Sweden). The patients were given ⁹⁹Tc^m-Sestamibi intravenously as soon as possible after the decision to give thrombolytic treatment. When the patients were in a clinically stable state after the thrombolytic treatment, myocardial perfusion was analysed with the gamma camera using single photon emission computerized tomography (SPECT). A second ⁹⁹Tc^m-Sestamibi tomography was carried out on the second to fourth day after the myocardial infarction. Data reconstruction was done with the ‘Bull's eye technique’. Nine patients received thrombolysis < 3 h from the onset of pain. In this group six patients (66%) improved their myocardial perfusion by > 10% after treatment, while all seven patients who received treatment ≥ 3 h after the onset of pain improved their myocardial perfusion by < 10%. This study emphasises the importance of early diagnosis and treatment of patients with acute myocardial infarction in order to salvage myocardium.     

Myocardial ischemia assessed by Tc99m MIBI SPECT and left ventricle regional systolic and diastolic function evaluated by tissue Doppler echocardiography

Background: Tc99m MIBI single-photon emission computed tomography (SPECT) study facilitates the evaluation of the regional myocardial perfusion and tissue Doppler echocardiography imaging facilitates the quantitative assessment of the regional systolic and diastolic function of the myocardium. The aim of the study was an assessment of the correlation between regional rest myocardial perfusion defects and regional rest systolic and diastolic myocardial velocities in patients with ischemic heart disease (IHD). Material and methods: In 40 IHD patients (33 men, 7 women) aged 43–74 years (mean 56 years) rest SPECT imaging with Tc99m MIBI and rest tissue Doppler examinations were performed. The control group consisted of 35 healthy sex and age matched pesons. The left ventricle was divided into 13 segments. The number of non-perfused segments in three myocardial perfusion regions (left anterior descending artery, circumflex artery, right coronary artery) was assessed in IHD patients. During tissue Doppler examination the maximal systolic and maximal early diastolic velocity of the myocardium in each segment were established in both examined groups. Results: The systolic and diastolic myocardial velocities were significantly lower in IHD group as compared to control group. In the IHD group statistically significant decrease of systolic and diastolic velocities in relation to the number of non-perfused segments was found. In comparing the linear regression slopes for systolic and for diastolic myocardial velocities in terms of intensification of perfusion defects, a more pronounced decrease in diastolic velocity was encountered. Conclusions: Both systolic and diastolic myocardial velocities are decreased in the myocardial regions with perfusion defects, but the reduction of the diastolic velocity is higher than the reduction of the systolic velocities. Thus our results indicate a good correlation between the intensity of perfusion abnormalities and myocardial velocities. The levels of diastolic dysfunction is more pronounced than the level of systolic dysfunction in the ischemic myocardium.     

Myocardial contrast echocardiography for predicting functional recovery after acute myocardial infarction

Myocardial contrast echocardiography (MCE) is a promising diagnostic tool for detecting microvascular integrity. The aim of the study was to investigate the comparative specificity and sensitivity of intravenous MCE, technetium-99m Sestamibi single-photon emission computed tomography (SPECT) and dipyridamole–dobutamine (DIDO) stress echocardiography for predicting functional recovery after coronary revascularization in patients with acute myocardial infarction (AMI). Methods: In a prospective, observational study, 17 consecutive patients short after AMI who received successful treatment with primary percutaneous coronary angioplasty (PTCA) plus stent-implantation were examined with DIDO (dipyridamole with 0.28 mg/kg over 4 min plus dobutamine up to 10 mcg/kg/min), MCE (10 ml 4 g, 400 mg/ml Levovist^® intravenously; second harmonic power imaging) within 12–24 h and resting perfusion SPECT within 48–72 h after PTCA. Functional recovery of regional contractile function after 6-month follow-up was the gold standard to assess viability. Results: The rate of agreement between SPECT and MCE was 69% and between SPECT and a positive response to stress echo was 76% for combined DIDO. MCE showed a higher sensitivity (96%) in the identification of viability than SPECT (77%) and combined DIDO alone (79%). Specificity was lower for viability recognition with MCE (58%) compared with SPECT (93%) and DIDO (87%). Conclusions: The wall motion response during DIDO echocardiography is useful in the prediction of recovery of regional and global ventricular function after revascularization in patients after AMI. Combined intravenous MCE and DIDO is more accurate in the diagnosis of stunned myocardium than Tc-99m-MIBI SPECT alone.     

Quantitative imaging of myocardial infarct in rats with high resolution pinhole SPECT

Small animal imaging of cardiovascular disease using single photon emission tomography (SPECT) can be used to provide quantitative measurements of myocardial infarct. The purpose of this study was to demonstrate the accuracy of pinhole SPECT imaging with [^99mTc]sestamibi for estimation of infarct size in a rat model of coronary artery disease. Nine rats had their left anterior descending artery ligated to induce a region of myocardial infarct. These animals were injected with 37 MBq [^99mTc]sestamibi, and, 1 h later, scanned on a pinhole SPECT system for 30 min. The defect size measured with SPECT, which was dependent on a threshold applied to the short axis circumferential profiles, was compared against the gold standard triphenyltetrazolium chloride (TTC) staining. The size of the perfusion deficit measured using [^99mTc]sestamibi SPECT compared very favorably with the TTC staining result, for threshold values in the range 50–70%. The optimum threshold was approximately 70%, giving an excellent correlation (R ²=0.89, p<0.001). Estimation of infarct size by [^99mTc] sestamibi SPECT yielded an excellent agreement with TTC staining. In conclusion, measurement of myocardial infarct with SPECT can be used to study the rat heart in vivo, and provides a quantitative measure of myocardial viability.     

双核素心肌显像对老年冠心病CTO病变PCI术的指导意义

目的评价99 Tcm-甲氧基异丁基异腈（99 Tcm-sestamibi,99 Tcm-MIBI）/18F脱氧葡萄糖（18F-fluorodeoxy glu-cose,18F-FDG）双核素心肌灌注/代谢显像技术（DISA）检测冠状动脉完全闭塞导致心力衰竭型冠状动脉粥样硬化性心脏病老年患者存活心肌对经皮冠状动脉支架术（Percutaneous coronary intervention,PCI）后心功能的改善情况。方法 41例经冠状动脉造影证实至少1支以上冠脉闭塞导致心力衰竭型冠心病的老年患者,PCI术前1周行99 Tcm-MI-BI/18F-FDG双核素心肌灌注/代谢显像检查,根据DISA结果,分为有心肌存活组和无心肌存活组。分别比较PCI术前后2组患者血浆BNP值及左室射血分数（LVEF）等心功能指标。结果有心肌存活组经PCI术后LVEF由41.12±5.97升至47.12±4.86,LVFS由16.79±5.64升至25.86±7.43,血NT-proBNP值由4287.25±401.56ng/L降至427.43±91.47ng/L;术前与术后比较,有显著统计学意义;无心肌存活组经PCI术后LVEF由40.03±3.48升至41.31±3.56,LVFS由16.35±5.86升至18.75±3.51,血NT-proBNP值由4495.32±347.72ng/L降至3827.53±97.28ng/L,术前与术后比较,无统计学意义。结论双核素心肌显像能有效检测冠状动脉完全闭塞致心力衰竭型冠心病老年患者存活心肌,而有存活心肌者PCI术后心功能得到明显改善。故双核素心肌显像对老年冠心病CTO病变行PCI术有指导意义。     

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT

Background Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique.Methods Fourteen consecutive patients underwent MCE, MRI and ^99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist^®. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or “patchy” perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal.Results At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT.Conclusion MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.     

Value of absence of a transient myocardial perfusion defect during stress myocardial perfusion study in patients undergoing major vascular surgery

Pre-operative cardiac assessment is important in the evaluation of patients undergoing major vascular surgery. Our study aims to evaluate the value of absence of a transient myocardial perfusion defect during radionuclide myocardial perfusion study for prediction of cardiac events (myocardial infarction, sudden cardiac death, unstable angina, coronary artery revascularization and congestive heart failure) in patients undergoing major vascular surgery. We studied 63 consecutive patients (ages 35–83 [avg. 64], male 39, female 24) with radiographically proven, abdominal aortic aneurysm or severe aortofemoral occlusive disease who underwent major vascular surgery (abdominal aortic aneurysm repair [38] or aortofemoral bypass [25]). The subjects all had multiple coronary artery risk factors (hypertension 48, diabetes 10, hyperlipidemia 23, tobacco use 39, family history of coronary artery disease 10), but a negative pre-operative stress myocardial perfusion study for myocardial ischemia. Of these 63 patients, 17 patients were able to exercise and achieve their adequate 85% maximal predicted heart rate. Thirty-eight patients received adenosine infusion of 140 g/kg/min for 6 min. Six patients received dipyridamole infusion of 0.56 mg/kg over 4 min. Two patients received dobutamine infusion at 5, 10, 20, 30, and 40 mg/kg/min. Of the 63 patients, 60 received 3–4 mCi of thallium-201 (²⁰¹Tl) and 3 patients received 8–9 mCi of technetium-99^m (^99mTc) at rest and 25–30 mCi ^99mTc during stress. The subjects all underwent major vascular surgery and were followed up to one year for any cardiac events. Of the 63, who underwent pre-operative cardiac assessment with myocardial perfusion testing, 25 had a fixed myocardial perfusion defect (scar) and none had evidence of transient myocardial perfusion defect (ischemia). One subject had coronary artery bypass grafting 11 months after aortofemoral bypass surgery. One died from a stroke one month after aortofemoral bypass surgery. Of the remaining 61 patients, none had any cardiac events up to one year after major vascular surgery.