骨髓间质干细胞治疗家猪急性心肌梗死的SPECT显像

目的评价心肌 SPECT 显像对自体骨髓间质干细胞治疗家猪心肌梗死的价值。方法选择21头中国小型家猪,应用闭胸经股动脉介入的方法制作心肌梗死模型。10余天后实验组(11头)在心肌梗死区移植培养的骨髓间质干细胞,对照组(10头)在梗死区植入培养液。移植前及移植后8周对2组进行(99)~Tc~m-甲氧基异丁基异腈(MIBI)心肌显像及图像半定量分析;同时进行超声心动图及免疫组织化学检查。结果心肌显像示实验组在移植后心肌异常节段数从46个下降至26个,心肌梗死的面积从(34±12)%缩小至(21±10)%,心肌缺血总分值(SS)从20.0±4.3下降至12.1±3.6,与对照组相比差异均有显著性(P<0.05)。与同期进行的超声心动图及免疫组织化学检查结果一致。结论骨髓间质于细胞移植可改善心肌缺血区血流灌注及心肌活力。心肌 SPECT 显像可准确观察骨髓间质干细胞在心肌梗死部位的存活情况。     

心肌灌注及代谢显像检测存活心肌及对心肌梗死伴左室功能不全患者治疗策略的影响

目的用99Tcm-甲氧基异丁基异腈(MIBI)SPECT和18F-脱氧葡萄糖(FDG)PET心肌灌注/代谢显像对陈旧性心肌梗死伴左室功能不全患者心肌存活状况及治疗策略进行评价。方法70例陈旧性心肌梗死伴左室功能不全[左室射血分数(LVEF)为(35±10)%]患者,均行99Tcm-MIBISPECT、18F-FDGPET心肌灌注/代谢显像预测存活心肌。灌注缺损、代谢填充(灌注-代谢不匹配)为心肌存活;灌注、代谢均缺损(灌注-代谢匹配)为心肌无存活;同时进行超声心动图检查评价左室壁运动、LVEF、左室舒张末径(LVDd)及收缩末径(LVDs)。血运重建术或内科保守治疗后3-6个月进行超声心动图复查,评价左室壁运动改善情况及LVEF、LVDd及LVDs的变化。结果41例患者接受血运重建术,29例患者接受内科保守治疗。心肌代谢显像判定为存活心肌节段≥20%的46例患者中,31例接受血运重建术(A1组)、15例内科保守治疗(A2组);存活心肌节段<20%的24例患者中,10例接受血运重建术(B1组),14例内科保守治疗(B2组)。4组患者基本临床情况无差异。血运重建术后,A1组LVEF由(37.19±9.52)%增至(46.10±7.62)%(P<0.05),LVDd由(57.62±5.89)mm降至(52.38±4.42)mm(P<0.01),LVDs从(44.4±9.53)mm降至(38.35±8.02)mm(P<0.05),存活心肌节段运动情况记分由(10.67±8.14)分改善为(6.77±6.32)分(P<0.05);上述指标在A2、B1、B2组治疗前后未见明显改变(P>0.05)。结论99Tcm-MIBISPECT、18F-FDGPET显像对心肌存活的评价有助于心肌梗死伴左室功能不全患者治疗策略的选择。     

PET-CT在冠状动脉疾病的临床应用

PET-CT可无创性检测心肌血流灌注、定量测定冠状动脉血流储备,并提供冠状动脉解剖影像、冠状动脉钙化积分,观察粥样斑块性质,对心肌存活性、心脏功能测定都有重要临床价值。将以上各种信息综合应用于临床,则对冠心病的诊断、治疗方案的选择及预后判断等具有重要意义。     

心肌代谢-灌注半定量评分在冠状动脉旁路移植术中的应用

目的评估放射性核素心肌显像代谢-灌注半定量评分在冠状动脉旁路移植术（CABG）中的应用价值。方法选择21例多支冠状动脉病变的冠心病患者进行前瞻性研究。所有患者术前均进行^99Tc^m-甲氧基异丁基异腈（MIBI）门控心肌灌注显像（G—MH）与^18F-脱氧葡萄糖（FDG）PET心肌代谢显像，评估心肌缺血的范围、程度及心肌活力。检查后2周内行CABG。所有患者术后第3个月随访行G—MH。结果G—MH和PET图像的定性和半定量分析均根据美国核心脏病学会（ASNC）提出的阅片指南，分别计算每一心肌节段的静息灌注评分（RS）、代谢-灌注差值（DS）及静息灌注总分（SRS）和代谢-灌注总差值（SDS）。心肌节段的DS〈0分即认为该部位心肌存活，反之则认为心肌活力丧失。在共420个心肌节段中，G—MH共检出164个缺血节段，其中93个节段活力丧失，71个节段存活。根据术前SDS结果，将患者分为3组：A组SDS≥0分，5例；B组-5分≤SDS〈0分，8例；C组SDS〈-5分，8例。随访G—MH发现上述3组术后左室射血分数绝对值较术前分别提高-3．60％，3．38％和6．88％。结论心肌代谢-灌注半定量评分可准确评价患者CABG后疗效，并可预测术后左室功能恢复程度。     

201Tl与13N-NH3、18F-FDG PET心肌显像判断存活心肌的对比研究

目的　比较再注射2 0 1T1心肌显像与联合应用13 N NH3 及18F 脱氧葡萄糖 (FDG)心肌PET显像判断存活心肌的临床价值。方法　 2 0例心肌梗死患者 ,行2 0 1T1SPECT负荷、再分布、再注射显像及13 N NH3 、18F FDGPET心肌显像。将左室分成 9个节段 ,以视觉评价法对放射性分布进行 4级评分。获得2 0 1T1SPECT再分布、再注射像及18F FDGPET显像的局部心肌摄取率 (%ID)。结果　PET判定为存活心肌的 48个节段中 ,45个节段 (93.8% ) 2 0 1T1再注射像也判定为存活心肌。在2 0 1T1再分布像示放射性分布严重低下的 2 4个节段 ,2 0 1T1再注射像与PET显像判定存活心肌的一致率为 87.5 % ,其中 37.5 %为存活心肌节段 ,5 0 %为无存活心肌节段。 2种显像方法的 %ID无明显差异 ,且呈显著正相关 (r=0 .72 2 )。结论　再注射2 0 1T1心肌显像判断存活心肌的准确性与PET心肌显像相似 ,有较大的临床应用价值。     

99Tcm-MIBI与18F-FDG双核素同时采集法心肌显像检测存活心肌

目的 评价辨99Tcm-甲氧基异丁基异腈(MIBI)与18F-脱氧葡萄糖(FDG)双核素同时采集法心肌显像(DISA SPECT)检测存活心肌的临床价值.方法 21例经彩超检查证实存在左室壁节段运动障碍的冠心病患者,进行DISA SPECT、冠状动脉造影(CAG)及经皮冠状动脉介人治疗(PCI),对所有狭窄病变行完全血运重建术.参照美国超声心动图学会16节段划分法获得心肌各运动异常节段DISA SPECT图像,并对心肌存活情况进行判定.DISA SPECT图像用目测半定量法分析.术后1,3和6个月时复查心脏超声,以冠状动脉血运重建后室壁节段收缩功能改善为判断存活心肌的"金标准",根据诊断试验四格表评价DISA SPECT检测存活心肌的价值.结果 21例冠心病患者共获得符合条件的室壁运动异常节段156个,根据"金标准"判断其中105个为存活心肌,51个为非存活心肌,DISA SPECT检测存活心肌的灵敏度、特异性、阳性预测值、阴性预测值、准确性分别是93.3%(98/105)、82.4%(42/51)、91.6%(98/107)、85.7%(42/49)、89.7%(140/156).结论 DISASPECT目测半定量法检测存活心肌有较高的临床价值.     

衰减校正处理对提高99Tcm-MIBI心肌显像准确性的价值

目的　探讨衰减校正(AC)处理对提高99Tcm-甲氧基异丁基异腈(MIBI)心肌显像诊断冠心病和判断存活心肌准确性的作用。方法　16例正常对照者和25例经冠状动脉造影证实的冠心病患者进行了99Tcm-MIBI心肌断层显像,分别应用AC和非衰减校正(NC)处理,其中9例冠心病患者在显像后1周内接受了经皮冠状动脉腔内成形术(PTCA)治疗。将左心室分成9个心肌节段,心肌各节段相对放射性分布值以左室心肌最高计数的百分率表达。结果　在正常对照组中,NC显示的心肌各节段放射性分布呈显著的不均匀性,后基底部与前壁的左室峰计数百分率(LVP%)相差26.9%;而在AC图中,左心室心肌放射性分布的均匀性明显改善,后基底部与前壁的LVP%相差仅5.6%。在冠心病的定位诊断中,经AC处理后,99Tcm-MIBI心肌显像对左前降支(LAD)和左回旋支(LX)检测的灵敏度可由常规NC显像的77%和58%分别提高到91%和89%(P<0.05),右冠状动脉(RCA)定位的特异性由NC的67%提高到88%(P<0.05)。在缺血区存活心肌判断中,当心肌节段的99Tcm-MIBI相对分布值小于30%,AC与NC结果相似;节段放射性分布值在30%～75%范围内,以PTCA术后心室壁活动改善为标准,AC对存活心肌检测的准确性明显高于NC,AC改善存活心肌判断的部位主要是下壁、后基底部和间隔部。结论　99Tcm-MIBI心肌显像的AC处理能明显改善整个心肌显像的图像质量,并在提高冠心病早期诊断与存活心肌判断中有独特价值。     

^99Tc^m—MIBI与^18F-FDG双核素同时采集法心肌显像检测存活心肌

目的评价^99Tc^m-甲氧基异丁基异腈（MIBI）与^18F-脱氧葡萄糖（FDG）双核素同时采集法心肌显像（DISA SPECT）检测存活心肌的临床价值。方法21例经彩超检查证实存在左室壁节段运动障碍的冠心病患者,进行DISA SPECT、冠状动脉造影（CAG）及经皮冠状动脉介入治疗（PCI）,对所有狭窄病变行完全血运重建术。参照美国超声心动图学会16节段划分法获得心肌各运动异常节段DISA SPECT图像,并对心肌存活情况进行判定。DISA SPECT图像用目测半定量法分析。术后1,3和6个月时复查心脏超声,以冠状动脉血运重建后室壁节段收缩功能改善为判断存活心肌的“金标准”,根据诊断试验四格表评价DISA SPECT检测存活心肌的价值。结果21例冠心病患者共获得符合条件的室壁运动异常节段156个,根据“金标准”判断其中105个为存活心肌,51个为非存活心肌,DISA SPECT检测存活心肌的灵敏度、特异性、阳性预测值、阴性预测值、准确性分别是93．3％（98／105）、82．4％（42／51）、91．6％（98／107）、85．7％（42／49）、89．7％（140／156）。结论D1SA SPECT目测半定量法检测存活心肌有较高的临床价值。     

冠心病无创性检查的研究进展

无创性检查方式是评价冠心病和亚l临床冠心病的有效手段,包括CT、核心脏病学、MRI以及图像融合.此综述重点阐述了各种无创性检查方式用于评价冠心病和亚临床冠心病的优缺点.利用CT可行钙化积分,对冠状动脉钙化程度进行定量分析,亦可行无创性冠状动脉造影.目前核心脏病学是评价心肌血流灌注应用最广泛的无创性检查方式,包括SPECT和PET,分别可对心肌血流和冠脉血流行半定量和定量分析.现研究多致力于无创性冠脉造影和MRI心肌血流灌注显像.如今图像融合设备亦迅猛发展,可同时包含解剖和功能信息,对诊断冠心病具有很大的价值.     

门控心肌灌注SPECT在冠心病方面的应用进展

门控心肌灌注SPECT能同时获得心肌血流灌注情况和左心室功能参数,是目前核素心脏检查中常用的方法。此法可重复性强,在临床应用广泛,为冠心病患者的诊断、危险度分层、心肌活力评价、治疗、预后及疗效的评价提供了可靠的依据。     

18-Fluorodeoxyglucose imaging with positron emission tomography and single photon emission computed tomography: cardiac applications

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 extensive viable myocardium, patients with predominantly scar tissue should be treated medically or evaluated for heart transplantation. Among the many viability tests, noninvasive assessment of cardiac glucose use (as a marker of viable tissue) with F18-fluorodeoxyglucose (FDG) is considered the most accurate technique to detect viable myocardium. Cardiac FDG uptake has traditionally been imaged with positron emission tomography (PET). Clinical studies have shown that FDG-PET can accurately identify patients with viable myocardium that are likely to benefit from revascularization procedures, in terms of improvement of left ventricular (LV) function, alleviation of heart failure symptoms, and improvement of long-term prognosis. However, the restricted availability of PET equipment cannot meet the increasing demand for viability studies. As a consequence, much effort has been invested over the past years in the development of 511-keV collimators, enabling FDG imaging with single-photon emission computed tomography (SPECT). Because SPECT cameras are widely available, this approach may allow a more widespread use of FDG for the assessment of myocardial viability. Initial studies have directly compared FDG-SPECT with FDG-PET and consistently reported a good agreement for the assessment of myocardial viability between these 2 techniques. Additional studies have shown that FDG-SPECT can also predict improvement of LV function and heart failure symptoms after revascularization. Finally, recent developments, including coincidence imaging and attenuation correction, may further optimize cardiac FDG imaging (for the assessment of viability) without PET systems.     

Assessment of myocardial viability by positron emission tomography

Accurate assessment of myocardial viability is critical for identifying patients likely to benefit from coronary revascularization. Positron emission tomography (PET) has several advantages over single photon emission computed tomography (SPECT), including higher sensitivity and specificity, as well as the ability to measure myocardial blood flow and myocardial metabolism in absolute terms, which is important in understanding the pathophysiology of ischemic cardiomyopathy. The most commonly used PET tracer is [18F]2-fluoro-2deoxy-D-glucose (FDG). The dependence of ischemic myocardium on glucose metabolism makes FDG an ideal tracer in this setting. Studies have shown positive and negative predictive values for the detection of viable myocardium in the range of 48-94%, and 73-96%, respectively. FDG is superior to SPECT using thallium or technetium myocardial perfusion agents, as well as echocardiography with dobutamine infusion. FDG PET also provides important prognostic information. Patients with evidence of myocardial viability by FDG PET have fewer cardiac events and survive longer if revascularized compared to patients who are treated medically. This article will review myocardial metabolism, PET procedures and interpretive criteria, as well as problems and limitations. Data from the literature regarding diagnostic and prognostic information will also be summarized.     

The integration of positron emission tomography into noninvasive cardiovascular diagnosis]

Cardiac positron emission tomography is a noninvasive imaging modality that can be used to assess regional myocardial blood flow and metabolism. This combined noninvasive approach to the evaluation of acute or chronic injury to the myocardium is superior to all other imaging modalities. With increasingly widespread use of positron emission tomography it is becoming evident that patients with impaired left ventricular ejection fraction (less than or equal to 35%) resulting from congestive heart failure and patients soon (72-96 h) after acute myocardial infarction in particular may benefit from definition of metabolically active myocardium to stratify therapeutic assessment.     

Simultaneous assessment of myocardial viability and function for the detection of hibernating myocardium using ECG-gated 99Tcm-tetrofosmin emission tomography: a comparison with 201Tl emission tomography combined with cine magnetic resonance imaging

The aims of this study were to evaluate the simultaneous assessment of myocardial viability and function for the detection of hibernating myocardium using ECG-gated 99Tcm-tetrofosmin single photon emission tomography (SPET), and to compare the technique with 201Tl SPET in combination with cine magnetic resonance imaging (MRI). Fifteen patients aged 41-70 years with impaired left ventricular function (mean LVEF 23.4 +/- 8.1%) and three-vessel coronary artery disease were studied before and after coronary artery bypass grafting (CABG). The following investigations were performed within the 3 months before surgery: stress/redistribution and separate-day rest 201Tl SPET with early and late imaging, stress and ECG-gated rest 99Tcm-tetrofosmin SPET, and resting cine MRI. Between 3 and 6 months post-surgery, stress/redistribution 201Tl SPET and cine MRI were repeated. Tracer uptake in nine segments of the left ventricle was graded visually and by quantitative analysis. Myocardial motion and thickening were graded visually from cine MRI and from gated 99Tcm-tetrofosmin SPET images. Segments were defined as hibernating pre-operatively if tracer uptake was moderately reduced or better but myocardial motion was severely hypokinetic or worse. The accuracy of pre-operative assessment was assessed by comparison with post-operative function assessed by MRI. The sensitivity and specificity for the prediction of functional improvement were 69% and 60% for late rest 201Tl uptake combined with MRI; 58% and 62% for rest 99Tcm-tetrofosmin uptake combined with MRI; and 62% and 45% when gated 99Tcm-tetrofosmin SPET was used to assess both tracer uptake and wall motion. In 21 of 135 segments, contractile function could not be assessed by gated 99Tcm-tetrofosmin SPET because of inadequate tracer uptake; function was improved in 5 (25%) of these segments after CABG. In conclusion, the combined assessment of viability and function using ECG-gated 99Tcm-tetrofosmin SPET is feasible and it allows the assessment of hibernating myocardium with similar accuracy to the combination of ungated 99Tcm-tetrofosmin SPET with MRI. Where tracer uptake is too poor for assessment of function, there is a low incidence of myocardial hibernation. However, ECG-gated 99Tcm-tetrofosmin SPET is not superior to 201Tl SPET combined with cine MRI in the identification of hibernation.     

Methodology governing the assessment of myocardial glucose metabolism by positron emission tomography and fluorine 18-labeled fluorodeoxyglucose

Positron emission tomography (PET) with fluorine 18-labeled fluorodeoxyglucose (FDG) has provided important insights into the alterations in myocardial glucose metabolism associated with normal cardiac physiology and pathophysiology. In patients with left ventricular dysfunction caused by coronary artery disease, PET-FDG studies have identified certain patterns of myocardial glucose metabolism relative to flow that are associated with viable myocardium. Consequently, in many centers, PET-FDG imaging is being used to identify patients with left ventricular dysfunction who are likely to benefit from coronary revascularization. However, myocardial glucose metabolism (and thus myocardial uptake of FDG) is markedly dependent on a variety of factors, particularly the substrate environment and level of myocardial perfusion. These and other factors must be considered to obtain and interpret myocardial FDG images accurately with respect to the underlying pathophysiologic process. In this review the impact of these factors on myocardial FDG imaging, as well as the relative advantages and disadvantages of approaches designed to optimize myocardial PET-FDG studies, will be discussed.     

Cardiac fusion imaging with low-dose computed tomography using prospective electrocardiogram gating

In a 66-year-old patient with prolonged episodes of chest pain, catheter angiography revealed total occlusions of the right coronary artery and the distal circumflex artery (CX) as well as 2 sequential significant stenoses in the proximal CX and one significant stenosis in the proximal left anterior descending artery (LAD). To identify the culprit lesions with their respective territory, noninvasive assessment of viability was performed by F-18 FDG positron emission tomography (PET) and fused with a low-dose computed tomography coronary angiography using prospective electrocardiogram gating. Fused PET/computed tomography coronary angiography images demonstrated a large scar in the inferior myocardium, corresponding to the total occlusion in the right coronary artery, viable myocardium in the territory of the CX, and infarcted scar tissue with partially preserved viability in the anterior myocardium, corresponding to the presumably recanalized lesion in the LAD. The patient was scheduled for revascularization of the lesions in the LAD and the CX to reverse dysfunctional but viable myocardial segments.     

Magnetic resonance imaging in determination of myocardial ischemia and viability: comparison with positron emission tomography and single-photon emission computed tomography in a porcine model

Background: In patients with chronic left ventricular dysfunction, the size of the viable cardiac muscle is correlated with the prognosis and the outcome of myocardial revascularization.

Purpose: To evaluate the diagnostic value of various imaging techniques in determination of myocardial ischemia and viability.

Material and Methods: A chronic myocardial ischemia animal model was established, in which 10 pigs underwent magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (²⁰¹Tl SPECT) before and 1-2 months after modeling. The size of myocardial ischemia and necrosis was judged, and the imaging manifestations were compared with pathologic findings.

Results: Seven of the 10 animals completed all examinations uneventfully. On dobutamine-stressed cine MRI, 10 (8.93%) segments were found to be akinetic. Perfusion was abnormal in 34 (30.35%) segments. Delayed hyperenhancement was observed in 12 (10.71%) segments. PET detected myocardial necrosis in 17 (15.18%) segments, and SPECT detected myocardial necrosis in nine (8.04%) segments. Histological examination with triphenyltetrazolium chloride (TTC) showed pale necrosis in 14 (12.50%) segments. The number of necrotic segments detected by PET was significantly greater than that by contrast-enhanced MRI (χ² = 5, P = 0.0253, kappa = 0.8028) and cine MRI (χ² = 7, P = 0.0082, kappa = 0.7079). It was also greater than that by TTC (χ² = 3, P = 0.0833, kappa = 0.8879), although the difference was statistically insignificant. The number of necrotic segments detected by SPECT was significantly smaller than that by TTC (χ² = 5, P = 0.0253, kappa = 0.7590), as was the number of necrotic segments detected by cine MRI (χ² = 4, P = 0.0455, kappa = 0.8100). There was no statistically significant difference in the detection of necrotic segments between contrast-enhanced MRI and TTC (χ² = 2, P = 0.1573, kappa = 0.9130).

Conclusion: Cardiac MRI can determine viable myocardium and clearly delineate the location and degree of myocardial necrosis. PET slightly overestimates the extent of the necrotic myocardium and is unable to distinguish transmural necrosis from subendocardial necrosis.     

Cardiac metabolism: A technical spectrum of modalities including positron emission tomography,single-photon emission computed tomography,and magnetic resonance spectroscopy

Noninvasive techniques for the assessment of cardiac metabolism are important for the detection of potentially salvageable tissue in jeopardized areas of the myocardium. The correct identification of hibernating and stunned myocardium in patients with severely depressed cardiac function can have vital therapeutic consequences for the patient. Changes in myocardial fatty acid and glucose metabolism during acute and prolonged ischemia can be traced by positron-emitting or gamma-emitting radiopharmaceuticals. Alternatively,³¹P-labeled magnetic resonance spectroscopy can be used for the assessment of high-energy phosphate metabolism. It is not yet clear which modality will emerge as the most useful in the clinical setting. Positron emission tomography (PET) that uses combinations of flow tracers and metabolic tracers offers unique opportunities for quantification and high-resolution static and rapid dynamic studies. Currently, assessment of glucose metabolism with¹⁸F-fluorodeoxyglucose is regarded as the gold standard for myocardial viability and prediction of improvement of impaired contractile function after revascularization. However, preserved oxidative metabolism may be required for potential functional improvement, and therefore assessment of residual oxidative metabolism by¹¹C-labeled acetate PET may prove to be more accurate than¹⁸F-fluorodeoxyglucose PET, which reflects both anaerobic and oxidative metabolism. Moreover, because fatty acids are metabolized only aerobically, they are excellent candidates for the clinical assessment of myocardial viability and prediction of functional improvement after revascularization. Especially derivatives of fatty acids that are not metabolized but accumulate in the myocyte are attractive for myocardial imaging. Examples are¹²³I-beta-methyl-p-iodophenyl pentadecanoic acid and 15-(o-¹²³I-phenyl)-pentadecanoic acid. These tracers can be detected by planar scintigraphy and single-photon emission computed tomography, which are more economical and widely available than PET. In addition, 511 keV collimators have been developed recently, making the detection of positron emitters by planar scintigraphy and single-photon emission computed tomography feasible. The experience with³¹P-labeled magnetic resonance spectroscopy in humans is still limited. With current magnetic resonance spectroscopic techniques, insufficient spatial resolution is achieved for clinical purposes, but the possibility of serial measurements to monitor rapid changes of phosphate-containing molecules in time makes magnetic resonance spectroscopy very valuable for the research of myocardial metabolism.     

Cardiac positron emission tomography imaging

Cardiac positron emission tomography (PET) imaging has advanced from primarily a research tool to a practical, high-performance clinical imaging modality. The widespread availability of state-of-the-art PET gamma cameras, the commercial availability of perfusion and viability PET imaging tracers, reimbursement for PET perfusion and viability procedures by government and private health insurance plans, and the availability of computer software for image display of perfusion, wall motion, and viability images have all been a key to cardiac PET imaging becoming a routine clinical tool. Although myocardial perfusion PET imaging is an option for all patients requiring stress perfusion imaging, there are identifiable patient groups difficult to image with conventional single-photon emission computed tomography imaging that are particularly likely to benefit from PET imaging, such as obese patients, women, patients with previous nondiagnostic tests, and patients with poor left ventricular function attributable to coronary artery disease considered for revascularization. Myocardial PET perfusion imaging with rubidium-82 is noteworthy for high efficiency, rapid throughput, and in a high-volume setting, low operational costs. PET metabolic viability imaging continues to be a noninvasive standard for diagnosis of viability imaging. Cardiac PET imaging has been shown to be cost-effective. The potential of routine quantification of resting and stress blood flow and coronary flow reserve in response to pharmacologic and cold-pressor stress offers tantalizing possibilities of enhancing the power of PET myocardial perfusion imaging. This can be achieved by providing assurance of stress quality control, in enhancing diagnosis and risk stratification in patients with coronary artery disease, and expanding diagnostic imaging into the realm of detection of early coronary artery disease and endothelial dysfunction subject to risk factor modification. Combined PET and x-ray computed tomography imaging (PET-CT) results in enhanced patient throughput and efficiency. The combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and noninvasive coronary angiography to myocardial perfusion imaging and quantification. Evaluation of the clinical role of these creative new possibilities warrants investigation.