99mTc-MIBI心肌灌注显像预测急性心肌梗死患者延迟PCI疗效的临床意义

目的评价^99mTc-MIBI心肌灌注显像在急性心肌梗死（AMI）患者延迟经皮冠状动脉介入治疗（PCI）策略中的意义。方法 55例未行急诊PCI的AMI患者,以术前静息及硝酸甘油介入^99mTc-MIBI心肌灌注显像结果分为有存活心肌组和无存活心肌组,观察两组PCI前后1周静息心肌灌注缺损计分变化及PCI前、PCI后12个月后超声心动图改变。结果有存活心肌组和无存活心肌组静息心肌灌注显像缺损积分PCI前分别为（11.66±0.43）、（12.41±0.64）分,PCI后分别为（7.02±0.56）、（10.09±0.45）分,两组PCI前后心肌血流灌注均有改善（P均<0.05）,有存活心肌组心肌血流灌注改善更显著（P<0.01）。超声心动图检测显示PCI前两组左室射血分数（LVEF）及左室舒张末期内径（LVEDD）比较有统计学差异（P<0.05或<0.01）,PCI后12个月有存活心肌组LVEF、LVEDD改善优于无存活心肌组（P<0.05或<0.01）。结论静息及硝酸甘油介入^99mTc-MIBI心肌灌注显像可作为判断AMI患者延迟PCI疗效的可靠方法。     

99mTc-MIBI心肌灌注断层显像鉴别诊断扩张型和缺血性心肌病

目的 探讨核素心肌显像对扩张型心肌病和缺血性心肌病的诊断价值。方法 对23例扩张型心肌病(dilated cardiomyopathy，DCM)和29例缺血性心肌病(ischemic cardiomyopathy，ICM)进行^99mTc—MIBI心肌断层显像，观察其在心肌的分布情况。结果 所有52例患者的显像均有放射性分布异常。DCM组47．8％(11／23)放射性均匀减低，34．8％(8／23)呈花斑样改变；ICM组则96．6％(28／29)有节段性放射性缺损，无花斑样改变病例。若以节段性放射性缺损作为诊断缺血性心肌病的标准则其敏感性为96．6％，特异性为93．3％；若以均匀减低和／或花斑样分布而无完全缺损节段作为扩张型心肌病的诊断标准，则DCM组有82．6％的病例符合。结论 ^99mTc—MIBI心肌断层显像的特征对扩张型心肌病和缺血性心肌病的诊断和鉴别诊断具有较高的应用价值，与心血管造影有较好的相关性。     

硝酸甘油介入99 mTc-MIBI心肌断层显像对存活心肌的评价

为评价硝酸甘油（NTG）介入99m锝-甲氧基异丁基异脯（99mTc－MIBI）心肌显像估测存活心肌的价值，对24例心肌梗死病人不同日行两种方案的99mTc－MIBI心肌显像：一种在静息状态进行，另一种在舌下含服NTG0．6mg后进行。8例经皮腔内冠状动脉成形术（PTCA）的病人术后2～4周随访了99mTc－MIBI静息显像。结果显示，99mTc－MIBI静息显像有118个心肌节段摄取正常，98个摄取异常（16个节段摄取减低，82个摄取严重减低），在98个摄取异常的节段中，NTG介入99mTc－MIBI显像有39个（39．80％）节段摄取增加。8例行PTCA的病人，NTG介入99mTC－MIBI显像证实为可逆性缺损的心肌节没有84．21％在PTCA后心肌灌注改善（存活心肌），而为NTG介入99mTc－MIBI显像证实为不可逆性缺损的心肌节段有88．24％在PTCA后心肌灌注无改善。NTG介入99mTc－MIBI显像预测存活心肌的准确性为86．11％。表明，NTG介入99mTc－MIBI心肌显像可提高缺血但存活心肌的检出率。     

冠状动脉腔内心电图与核素心肌显像识别存活心肌的对照研究

目的 　 对照研究冠状动脉腔内心电图 (intracoronaryelectrocardiogram ,IC ECG)与核素心肌显像在识别存活心肌中的准确性及实用性 ,观察IC ECG是否较核素心肌显像具有准确率高、简便易行等优点 ,并从心电学角度为临床判断存活心肌提供一个新的指标。　方法　 4 2例心肌梗死患者 (梗死后 2周～ 3个月 ) ,采用经皮冠状动脉腔内成形术 (PTCA)支架术前静脉滴注小剂量多巴酚丁胺 (3μg·kg- 1 ·min- 1 )时合用舌下含服硝酸甘油 (0 5mg) 99mTc MIBI心肌显像 ,与术后 3周静息99mTc MIBI心肌显像的对照观察多巴酚丁胺与硝酸酯合用预测存活心肌的准确度及安全性。所有患者于PTCA支架术中同步记录IC -ECG及体表心电图 ,观察、测算J点后 4 0ms处ST段改变。根据IC ECG的ST段改变将患者分为 2组 ,A组 :IC ECG在术中ST段抬高 >0 2mV ;B组 :IC ECG在术中ST段抬高 <0 2mV。以术后 3周时静息99mTc MIBI心肌显像识别存活心肌者为阳性对照 ,观察IC ECG的ST段改变是否能够预测存活心肌。　结果　PTCA支架术前静息99mTc MIBI心肌灌注显像共有 16 4个节段心肌摄取异常。药物介入99mTc MIBI心肌灌注显像及PTCA支架术后 3周静息99mTc MIBI心肌灌注显像放射性分布异常节段心肌血流灌注改善。以PTCA支架术后 3周为标准 ,药物     

冠状动脉造影正常的心肌梗塞患者核素心肌灌注显像

目的 :分析冠状动脉造影正常的心肌梗塞患者核素心肌灌注显像表现。　　方法 :回顾总结了 18例冠状动脉造影正常的心肌梗塞患者 99m锝 -甲氧基异丁基异腈 (99m Tc- MIBI)静息心肌断层显像。　　结果 :18例心肌梗塞患者心肌灌注显像均显示异常 ,12例有节段性缺损 ,6例未见缺损但可见心肌节段性稀疏。心肌灌注显像对心肌梗塞的定位与心电图 Q波比较 ,显示病变部位更明确。　　结论 :心肌灌注显像提供了冠状动脉造影正常的心肌梗塞患者心肌损伤部位及程度。     

二硝酸异山梨酯介入99mTc-MIBI心肌显像对梗死后存活心肌的判定及比较

目的:评价二硝酸异山梨酯(Isoket)介入99mTc-甲氧基异丁基异腈(MIBI)心肌断层显像检测心肌梗死后存活心肌的价值,并观察99mTc-MIBI心肌显像评价急性心肌梗死(AMI)与陈旧性心肌梗死(OMI)存活心肌的差异.方法:对16例OMI患者和12例AMI患者,分别进行静息99mTc-MIBI显像和Isoket静脉介入后99mTc-MIBI心肌断层显像.结果:静息99mTc-MIBI显像出现灌注异常185个节段,根据心肌放射性分布情况打分,平均得分为15.1±3.8,Isoket介入99mTc-MIBI显像后出现灌注异常节段为160个,平均得分为10.8±1.6,两者比较差别有显著性(P＜0.01).静息99mTc-MIBI显像出现的185个灌注异常的节段中16例OMI占102个,12例AMI占83个;Isoket介入后87个得到不同程度改善的节段中OMI占40个,AMI占47个,两者比较,P＜0.05.结论:Isoket介入99mTc-MIBI显像与静息99mTc-MIBI显像比较可明显提高对存活心肌检测的灵敏度,并对AMI存活心肌的检出率要明显高于OMI.     

^201Tl静息—再分布显像后行再注射心肌断层显像检测存活心肌的价值

为评价＾２０１Ｔｌ静息－再分布显像后行再注射显像检测存活心肌的价值,对２４例心肌梗死患者行＾２０１Ｔｌ静息再分布－再注射显像。８例经皮穿刺腔内冠状动脉成形术（ＰＴＣＡ）的患者术前及术后２周￣４周随访了超声心动图,结果显示＾２０１Ｔｌ静息显像有９７个心肌节段放射性摄取异常,其中４ｈ再分布显像有可逆性灌注缺损３１个节段,再注射显像均为可逆性缺损,再分布显像为不可逆性灌注缺损的６６个节段,其中９个节段（     

高血压伴胸痛与心肌缺血的心肌核素显像分析

目的　探讨冠状动脉造影正常的高血压伴胸痛患者 SPECT心肌负荷显像特点及临床意义。方法　应用 99Tcm-甲氧基异丁基异腈 ( MIBI)门控心肌灌注断层显像定性与半定量记分法 ,比较了 2 0例冠状动脉造影 ( CAG)正常的高血压患者及正常对照组运动前后心肌显像特点。结果　 ( 1)心肌灌注断层分析 :高血压组心肌灌注显像阳性率为 65 % ,明显高于对照组 ( P<0 .0 5 ) ,其中 47( 75 .8% )个节段为可逆性缺损 ,8( 12 .9% )个节段为部分可逆性缺损 ,3 ( 4 .8% )个节段为固定性缺损 ,另有 4( 6.5 % )个节段存在反向分布 ;高血压组 7例心室壁肥厚患者 ,与 13例无心室壁肥厚患者心室壁节段灌注异常比较 ,两者之间差异显著 ( P<0 .0 5 )。 ( 2 )心功能参数分析 :高血压组运动负荷显像、静息显像左心室射血分数 ( L VEF )值测定未见明显差异。高血压组患者运动负荷显像左心室舒张末期心室容积 ( LVEDV)平均为 66.4± 12 .5 3 ,明显低于静息显像 L VEDV 73 .6± 14 .2 3 ( P<0 .0 0 1)。结论　 ( 1)心肌灌注显像异常可以发生在 CAG正常有 /或无心肌肥厚的高血压患者中 ,但随着心肌肥厚的加重 ,心肌缺血有加重趋势。 ( 2 ) CAG正常的高血压患者可能存在冠状动脉血流储备功能下降     

静息门控心肌灌注显像鉴别诊断缺血性和扩张型心肌病

目的:探讨静息门控心肌灌注显像(GMPS)对扩张型心肌病(DCM)和缺血性心肌病(ICM)的诊断价值.方法:对20例DCM和70例ICM进行~(99m)Tc-MIBI静息GMPS,观察2组心肌血流灌注情况及心功能指标.结果:ICM组心肌灌注显像呈节段性灌注异常;DCM组为非节段性分布的、散在的稀疏区.DCM组的左室射血分数比ICM组明显降低,舒张末心腔容积、收缩末心腔容积及心脏的重量比ICM组明显增大(P<0.01),差异有统计学意义.结论:~(99m)Tc-甲氧基异丁基异腈静息GMPS对DCM和ICM的诊断和鉴别诊断具有较高的应用价值.     

心电图ST段改变与99mTC—MIBI心肌灌注显像对比分析

为分析心电图ST段改变与^99m“TC—MIBI心肌灌注显像诊断心肌缺血。对126例心电图ST段改变患者同时行^99mTC—MIBI静息心肌灌注显像。126例均为我院门诊及住院患者，临床诊断冠心病或可疑冠心病。其中男性94例,女性32例，年龄35～72岁，进行2次以上心电图检查．均有ST段改变。同时行^99mTC—MIBI静息心肌灌注显像，采用Elscint APEX—SPX 6HR SPECT静息状态下采集，断层处理。连续两层并在两个不同方向的相应节段上，出现放射性分布减低区,考虑为心肌缺血。     

Comparison of rest thallium-201 imaging and rest technetium-99m sestamibi imaging for assessment of myocardial viability in patients with coronary artery disease and severe left ventricular dysfunction

Objectives. We prospectively compared myocardial uptake of thallium-201 (²⁰¹Tl) at rest with rest technetium-99m (^99mTc) sestamibi uptake in the same patients, using quantitative single-photon emission computed tomography (SPECT).

Background. Because of only slightly delayed redistribution, ^99mTc-sestamibi uptake at rest may be less than ²⁰¹Tl uptake, thereby underestimating the extent of viability.

Methods. Twenty patients (2.25 stenoses per patient) with a mean left ventricular ejection fraction of 33 ± 2% underwent early and 3-h delayed rest ²⁰¹Tl SPECT, rest ^99mTc-sestamibi SPECT and two-dimensional echocardiography.

Results. The 280 scan segments were classified as either a normal, mild reduction in viability, defined as delayed ²⁰¹Tl uptake ≤75% and ≥5%, or a severe reduction in viability, defined as delayed ²⁰¹Tl uptake <50%. Mild and severe defects were further classified as fixed or having rest ²⁰¹Tl redistribution. Comparisons by patients were made using repeated measures analysis of variance and Dunnett's multiple comparisons test to compare ^99mTc-sestamibi with initial rest ²⁰¹Tl and delayed ²⁰¹Tl uptake. Twenty patients had at least one mild fixed defect (95 total segments). The average percent uptake in these defects for initial ²⁰¹Tl, delayed ²⁰¹Tl and ^99mTc-sestamibi was 62.5 ± 2.7%, 63.1 ± 7.1% and 67.3 ± 9.7%, respectively (p = NS). Twelve patients (27 segments) had mild redistribution defects on serial rest ²⁰¹Tl imaging. The average percent uptake was 61.6 ± 5.2% for initial ²⁰¹Tl, 67.0 ± 9.1% for delayed ²⁰¹Tl and 67.7 ± 12.4% for ^99mTc-sestamibi defects. Technetium-99m sestamibi uptake was not significantly different than that for delayed ²⁰¹Tl but was significantly greater than initial ²⁰¹Tl uptake. Seventeen patients (52 segments) had severe fixed ²⁰¹Tl defects. The average percent uptake was 38.9 ± 7.3% for initial ²⁰¹Tl, 38.3 ± 12.2% for delayed ²⁰¹Tl and 42.7 ± 14.2% for ^99mTc-sestamibi defects in these patients (p = NS). Ten patients (19 segments) had severe redistribution defects on rest ²⁰¹Tl imaging. The average percent uptake was 37.0 ± 8.5% for initial ²⁰¹Tl, 42.9 ± 8.6% for delayed ²⁰¹Tl and 44.5 ± 11.3% for ^99mTc-sestamibi defects. As was seen for mild ²⁰¹Tl redistribution defects, ^99mTc-sestamibi uptake was significantly higher than initial ²⁰¹Tl uptake, but not significantly different than delayed ²⁰¹Tl uptake in these severe defects.

Conclusions. Technetium-99m sestamibi uptake after injection at rest is comparable to ²⁰¹Tl uptake after injection at rest in patients with severe coronary artery disease and left ventricular dysfunction, suggesting comparable worth for viability assessment.     

Cardiac imaging in women: use of radionuclide myocardial perfusion imaging and echocardiography for acute chest pain

Evidence for the value of noninvasive cardiac imaging in patients for the detection of ischemic heart disease has traditionally come from trials using male patients. The application of such technology for women is often presumptive. Because there is an overall lower prevalence of ischemic heart disease in women, difference in body habitus, and smaller heart size, cardiac imaging in women presents unique challenges for imaging specialists and cardiologists. With the introduction of technetium-99 meters perfusion agents, gated single-photon emission computed tomography, and attenuation correction, myocardial perfusion imaging (MPI) in women has achieved a high sensitivity and specificity for the detection of coronary artery disease similar to that observed in men. With harmonic imaging and myocardial contrast agents, two-dimensional echocardiography offers comparable diagnostic accuracy in women. More importantly, MPI and stress echocardiography have prognostic value in predicting future cardiovascular events. The severity and extent of the single-photon emission computed tomography myocardial perfusion defects independently predict future cardiovascular events. Myocardial perfusion rest imaging during acute chest pain has a 99% negative predictive value of subsequent cardiovascular events, and a positive study MPI is the most important predictor for future cardiac events. Both MPI and stress echocardiography can direct high-risk patients to more invasive management or selectively identify lower-risk patients, allowing safe discharge from the emergency department and unnecessary hospitalization. Using a triage approach incorporating MPI or rest echocardiography in patients with acute chest pain results in significant cost savings. However, data on rest imaging in women during acute chest pain are still lacking.     

Evaluation of myocardial uptake of 99mtechnetium pyrophosphate in clinical exercise-induced ventricular ischemia.

Although acute infarction of the myocardium is known to accumulate 99mtechnetium pyrophosphate, it is not entirely clear that ischemia alone without necrosis does not result in abnormal uptake of 99mtechnetium pyrophosphate. The present study investigates whether transient myocardial ischemia is associated with localization of 99mtechnetium pyrophosphate by evaluating images obtained with the scintillation camera at rest and after exercise in 15 patients with unequivocal myocardial ischemia. All patients had angina pectoris, multivessel coronary artery stenoses by selective arteriographic studies, and electrocardiographic ischemic responses on treadmill exercise. Eleven of the 15 patients also underwent radionuclide imaging with 81rubidium at rest and after exercise; the results demonstrated scintigraphic ischemia. The scintiscans with 99mtechnetium pyrophosphate revealed no evidence of increased myocardial radioactivity after exercise compared to rest in 14 of the 15 patients. In contrast, myocardial activity was observed with 99mtechnetium pyrophosphate after treadmill exertion in the remaining patient, in whom a small subendocardial infarction appeared to have occurred with the exercise. It is concluded from these results that transient myocardial ischemia does not cause localization of 99mtechnetium pyrophosphate. These findings support the specificity of abnormal localization of 99mtechnetium pyrophosphate for acute myocardial infarction.     

Combined assessment of technetium-99m SESTAMIBI planar myocardial perfusion images at rest and during exercise with rest/exercise left ventricular wall motion studies evaluated from gated myocardial perfusion studies.

The favorable physical characteristics of technetium-99m-labeled 2-methoxy-2-methylisopropyl-1-isonitril (Tc-SESTAMIBI) enable the combined evaluation of both myocardial perfusion and left ventricular wall motion. To assess the potential of rest and exercise regional myocardial function as an adjunct to planar myocardial perfusion imaging, 60 patients with coronary artery disease and documented arteriographic findings were studied with both protocols during a single study. Exact segmental concordance between myocardial perfusion and wall motion studies was 77% (701/900 segments). Overall sensitivity and specificity to detect hemodynamically significant coronary artery disease with Tc-SESTAMIBI myocardial perfusion imaging were 89% and 79%, respectively, with resting wall motion studies 83% and 71%, respectively, and with rest/exercise wall motion studies, 85% and 71%, respectively. If the results of both perfusion and rest/exercise studies were combined, sensitivity increased to 96% and specificity decreased to 64%. The differences with perfusion studies alone were not statistically significant. Thus despite a good correlation between regional left ventricular function and perfusion, no statistically significant incremental diagnostic value was found when the results of both perfusion and wall motion studies were combined.     

Incremental value of parametric quantitative assessment of myocardial perfusion by triggered Low-Power myocardial contrast echocardiography

OBJECTIVES: The purpose of this study was to compare the assessment of myocardial perfusion by myocardial parametric quantification (MPQ) with technetium-99m sestamibi single-photon emission computed tomographic (SPECT) imaging in humans. BACKGROUND: Accurate visual interpretation of myocardial contrast echocardiographic (MCE) images is qualitative and requires considerable experience. Current computer-assisted quantitative perfusion protocols are tedious and lack spatial resolution. Myocardial parametric quantification is a novel method that quantifies, color encodes, and displays perfusion data as a set of myocardial parametric images according to the relative degree of perfusion. METHODS: Forty-six consecutive patients underwent prospective stress/rest technetium-99m sestamibi gated-SPECT imaging and MCE using intravenous Optison or Definity. Apical two- and four-chamber cine loops at rest and after dipyridamole (0.56 mg/kg) stress were acquired. For each patient, the following assessments of myocardial perfusion were performed: 1). visual cine-loop assessment (VIS); 2). MPQ assessment; and 3). combined VIS + MPQ assessment. RESULTS: The segmental rates of agreement for myocardial perfusion with SPECT were 83%, 89%, and 92% (kappa = 0.46, 0.58, and 0.68) for VIS, MPQ, and VIS + MPQ, respectively. Similar trends were seen for the classification of the presence or absence of a moderate to severe perfusion defect, with the agreement for VIS, MPQ, and VIS + MPQ being 92%, 97%, and 97%, respectively. CONCLUSIONS: Myocardial parametric quantification demonstrates good agreement with SPECT and incremental agreement with VIS. Analysis strategies that incorporate MPQ demonstrate better agreement with SPECT than visual analysis alone.     

099mTc—MIBI硝酸异山梨酯介入显像对冠脉支架置入术后心肌血流灌注的评估

目的：探讨99mTc锝-甲氧基异丁基异腈（99mTc—methoxyisobutyl isonitrile,Tc—MIBI）评估冠状动脉支架置入术（支架置入术）后损伤区心肌细胞血流灌注状况的价值。方法：40例行支架置入术患者,分别在置入术前、后进行99mTc—MIBI心肌静态显像及其硝酸异山梨酯（ISDN）介入显像,对比分析损伤区心肌细胞血流灌注改善程度。结果：40例患者冠状动脉共有360个节段。术前Tc—MIBIISDN介入显像异常10g个节段（29．2％）,显著少于Tc—MIBI静态显像异常的178个节段（49．4％,P〈0．01）。支架置入术后ISDN介入显像异常91个（25．3％）节段也显著少于静态显像异常的112个节段（31．1％,P〈0．05）。结论：99mTc—MIBI—ISDN介入显像较99mTc—MIBI心肌静态显像更能反映支架置入术后心肌血流灌注情况。     

Segmental myocardial contractility versus perfusion in Kawasaki disease with coronary arterial aneurysm

The impact of Kawasaki-related coronary injury on the myocardium was evaluated in 13 patients with persistent coronary aneurysm after a follow-up period of 7.92+/-3.97 years (range 1.8 to 14.3). Myocardial segmental perfusion and contractility integrity were assessed by resting and exercise echocardiography and technetium-99 (Tc-99m) sestamibi scan. Eight patients (61.5%) had giant aneurysms (> or = 8 mm) and 9 had multivessel involvement; the mean diameter of the largest aneurysm was 8.6+/-2.5 mm (range 5 to 14). During the acute phase, myocardial infarction occurred in 1 patient and coronary thrombosis in another. At the latest echocardiographic evaluation, the mean aneurysm diameter was 6.8+/-2.4 mm (range 4.5 to 12), there was persistent giant aneurysms in 5 of 8 patients, and 3 of 9 patients had multivessel involvement. Coronary angiography demonstrated stenosis in 7 of 10 patients, with multiple levels in 2. At sestamibi scan, all 13 patients had perfusion anomalies at rest, whereas only 7 had detectable hypokinesia on echocardiography. With exercise, perfusion returned to near normal in 3 patients, improved in 3, remained unchanged in 4, and worsened in 3 patients. Segmental contractility similarly deteriorated in the latter 3 patients but also in 2 patients whose perfusion scan had improved with exercise. Three patients, normal at rest, developed segmental hypokinesia during exercise. When present, the location of observed changes in contractility on stress echocardiography corresponded to that of perfusion defect. In conclusion, abnormal myocardial perfusion is present long term after complicated Kawasaki disease, the worst anomalies accompanying persistent giant aneurysms. Unfavorable perfusion response was coupled with abnormal contractility; however, enhanced perfusion with exercise correlated poorly with segmental contractility response.     

Gated technetium-99m sestamibi for simultaneous assessment of stress myocardial perfusion,postexercise regional ventricular function and myocardial viability: Correlation with echocardiography and rest thallium-201 scintigraphy

Objectives. This study compares technetium-99m sestamibi (sestamibi) electrocardiographic (ECG) gated single-photon emission computed tomography (gated SPECT) and echocardiography for the evaluation of myocardial function and assesses the feasibility of single-injection, single-acquisition stress perfusion/rest function technetium-99m sestamibi-gated SPECT as an alternative to conventional stress/rest imaging for assessment of myocardial perfusion and viability.Background. Simultaneous assessment of stress perfusion and rest function is possible with gated SPECT acquisition of stress-injected technetium-99m sestamibi.Methods. Rest thallium-201 SPECT followed by stress sestamibigated SPECT (acquired 0.5 to 1 h after sestamibi injection) was performed in 58 patients. Echocardiography was performed immediately after or before gated SPECT in 43 of the patients. All studies were analyzed by semiquantitative visual scoring. Sestamibi-gated SPECT studies were read for stress perfusion and rest wall motion and thickening. Reversibility on sestamibi-gated SPECT was defined as the presence of a definite stress defect with normal or mildly impaired wall motion or thickening on gated SPECT.Results. There was high segmental score agreement between gated SPECT and echocardiography for wall motion (91%, kappa = 0.68, p < 0.001) and thickening (90%, kappa = 0.62, p < 0.001). Correlation for global wall motion (r = 0.9S, p < 0.001) and thickening (r = 0.96, p < 0.001) scores between the two modalities was excellent. In 32 patients without previous myocardial infarction, there was excellent agreement for reversibility between stress sestamibi-gated SPECT and rest thallium-201/stress sestamibi (98%, kappa = 0.93, p < 0.01). However, in 26 patients with previous infarction, discordance between the two approaches was frequent, with 26% (20 of 78) of nonreversible defects by stress sestamibi-gated SPECT being reversible by rest thallium-201/stress sestamibi and 21% (23 of 112) of reversible defects by stress sestamibi-gated SPECT being nonreversible by rest thallium-201/stress sestamibi.Conclusions. Gated SPECT of stress-injected sestamibi correlates well with echocardiographic assessment of regional function and thus adds information to perfusion SPECT. In patients without previous myocardial infarction, a single-injection stress perfusion/rest function approach using sestamibi-gated SPECT can substitute for conventional stress/rest myocardial perfusion imaging, adding a rest perfusion study only if there are nonreversible defects or consideration of attenuation artifacts. In patients with previous myocardial infarction, the gated SPECT approach does not replace the need for a rest perfusion study.     

Evaluation of myocardial infarction by radioisotope myocardial imaging with special reference on thallium-201 myocardial perfusion imaging

One hundred and three patients with myocardial infarctions were studied with 201-thallium chloride and/or 99m-technetium pyrophosphate myocardial imaging and were followed-up for an average of 23 months. There were 24 false negative cases with 201-thallium chloride, but no deaths or serious complications occurred during the follow-up period in these false negative cases. There were six patients with widened QRS complexes (more than 0.12 seconds) without bundle branch blocks and in three of them myocardial infarction was not identified by electrocardiography. However, there were large myocardial perfusion defects in the anterior-inferior wall of the left ventricle. All of this group of patients died suddenly during the follow-up period. The incidence of complications and mortality rose sharply in patients whose myocardial perfusion defects detected by thallium-201 were larger than 40% of the entire left ventricle. The myocardial infarction areas measured by 99m-technetium pyrophosphate were 28.5 +/- 9.8 cm2 in non-survivors and 16.5 +/- 1.7 cm2 in survivors. In addition, ten patients with acute myocardial infarction were studied by double scan methods with thallium-201; myocardial perfusion defect areas were reduced from 29 +/- 3% of the entire left ventricle to 19 +/- 4% by nitrate administration, indicating that there were reversibly ischemic areas in acute myocardial infarction which could be transiently reduced by nitrate. Thus, the study suggests the possibility of decreasing myocardial perfusion defects in the early phase of acute myocardial infarction, leading to a better long term prognosis for the patients.