实时心肌声学造影对冠心病患者心肌灌注的定量评价

目的探讨实时心肌声学造影(RTMCE)定量分析冠心病患者心肌血流量的临床应用价值。方法对20例冠脉造影左前降支冠脉狭窄>75%以上的冠心病患者(观察组)和20例健康体检者(对照组)行静息状态下RTMCE检查,同时应用超声心动图检测造影剂峰值密度(A)、心肌血流速率(β)、心肌血流量(MBF,MBF=A×β)、左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)、射血分数(EF)、舒张早期峰值血流速度(Emax)、舒张晚期峰值血流速度(Amax)。比较两组相应节段的心肌灌注情况和心脏功能。结果观察组β及MFB均显著低于对照组(P均<0.01),LVEDD、LVSED、EF、Emax、Amax、Emax/Amax、Dt等两组比较无明显差异。结论冠心病患者心肌血流速度减慢,存在心肌微循环损伤;RIMCE可定量评价缺血心肌的血流灌注状况。     

A head-to-head comparison of infusion and bolus doses of adenosine for stress myocardial contrast echocardiography

BACKGROUND: This study was a head-to-head, intraindividual comparison of the diagnostic accuracy and side effect profile of bolus and infusion administration of adenosine for stress myocardial contrast echocardiography (MCE). METHODS: Adenosine MCE was performed in 64 subjects, referred for stress thallium-201 single-photon emission computed tomography (SPECT) for known or suspected CAD. Each patient received adenosine by multiple boluses (6-12 mg/bolus) and infusion (140 mug/kg per min for 6 min) forms in random order, given at least 20 minutes apart. RESULTS: No prolonged or serious adverse events occurred during either adenosine bolus or infusion. Compared to SPECT imaging, the sensitivity, specificity, and concordance for the diagnosis of CAD were 77%, 87%, and 82% for adenosine infusion MCE and 81%, 90%, and 86% for adenosine bolus MCE, respectively. CONCLUSIONS: Both adenosine infusion and adenosine bolus protocols are safe for MCE in humans and can be used for the diagnosis of CAD.     

腺苷负荷试验心肌灌注显像对冠心病的诊断价值

目的:分析腺苷负荷试验心肌核素显像对于冠心病诊断的敏感性、特异性及其特点,评价其诊断冠心病的临床价值.方法:对68例临床疑诊冠心病患者,将其腺苷负荷试验心肌灌注显像结果与冠状动脉造影(CAG)结果进行对比分析.结果:在68例患者中,36例CAG阳性,其中腺苷心肌灌注显像检出病变33例(91.7%),未检出病变3例(8.3%);32例CAG阴性,其中腺苷心肌灌注显像异常3例(9.4%),正常29例(90.6%);腺苷心肌灌注显像对冠心病诊断的敏感性92.3%,特异性90.6%.结论:腺苷核素心肌灌注显像诊断冠心病敏感性及特异性均较高,是协助诊断冠心病的有效的无创性检查方法.     

Real time myocardial contrast echocardiography during supine bicycle stress and continuous infusion of contrast agent. Cutoff values for myocardial contrast replenishment discriminating abnormal myocardial perfusion

BACKGROUND: Myocardial contrast echocardiography (MCE) is a new imaging modality for diagnosing coronary artery disease (CAD). OBJECTIVE: The aim of our study was to evaluate feasibility of qualitative myocardial contrast replenishment (RP) assessment during supine bicycle stress MCE and find out cutoff values for such analysis, which could allow accurate detection of CAD. METHODS: Forty-four consecutive patients, scheduled for coronary angiography (CA) underwent supine bicycle stress two-dimensional echocardiography (2DE). During the same session, MCE was performed at peak stress and post stress. Ultrasound contrast agent (SonoVue) was administered in continuous mode using an infusion pump (BR-INF 100, Bracco Research). Seventeen-segment model of left ventricle was used in analysis. MCE was assessed off-line in terms of myocardial contrast opacification and RP. RP was evaluated on the basis of the number of cardiac cycles required to refill the segment with contrast after its prior destruction with high-power frames. Determination of cutoff values for RP assessment was performed by means of reference intervals and receiver operating characteristic analysis. Quantitative CA was carried out using CAAS system. RESULTS: MCE could be assessed in 42 patients. CA revealed CAD in 25 patients. Calculated cutoff values for RP-analysis (peak-stress RP >3 cardiac cycles and difference between peak stress and post stress RP >0 cardiac cycles) provided sensitive (88%) and accurate (88%) detection of CAD. Sensitivity and accuracy of 2DE were 76% and 79%, respectively. CONCLUSIONS: Qualitative RP-analysis based on the number of cardiac cycles required to refill myocardium with contrast is feasible during supine bicycle stress MCE and enables accurate detection of CAD.     

13N-NH3PET腺苷负荷—静息心肌灌注显像在冠状动脉病变功能学评价中的应用价值

目的探讨13N-NH3PET腺苷负荷—静息心肌灌注显像（MPI）在疑诊或确诊冠心病患者冠脉病变功能学评价中的应用价值。方法 30例疑似或确诊的冠心病患者,均接受13N-NH3PET腺苷负荷—静息MPI和冠状动脉造影（CAG）检查。结果用13N-NH3PET腺苷负荷—静息MPI评估30例患者197个冠状动脉节段供血区,结果50个节段供血区确定为存活心肌（24个节段供血区发现可逆性灌注缺损,26个节段供血区呈固定性灌注缺损）,3个节段供血区确定为无存活心肌,其余144个节段供血区为正常心肌。以CAG发现≥50%狭窄为CAG检查结果阳性标准,30例中MPI与CAG结果相符合者24例。阳性22例、假阳性5例、假阴性1例、阴性2例。敏感度95.65%、特异度28.57%、阳性预测值81.48%、阴性预测值66.67%。以CAG发现≥75%狭窄为CAG阳性标准,30例中MPI结果与CAG结果相符合者25例。其中阳性22例、假阳性5例、假阴性0例、阴性3例。敏感度为100%、特异度为37.5%、阳性预测值为81.48%、阴性预测值为100%。结论 MPI用于疑似或确诊冠心病患者冠状动脉功能学评价效果较好。     

超声四维应变技术结合实时心肌超声造影技术评价冠心病患者左室心肌灌注及运动功能改变的价值

目的 探索四维应变技术（4D-SI）结合实时心肌超声造影技术（MCE）评价冠心病患者心肌灌注及运动功能的临床价值。 方法 选取经冠状动脉造影确诊为冠心病的患者 30 例,血供异常的心肌节段按供血冠脉狭窄程度分为轻度、中度和重度狭窄组,并选取 15 例健康体检者作为正常对照组。所有分组均进行 MCE 和 4D-SI 检查,得出长轴应变 (4D-GLPS) 、环向应变 (4D-GCPS) 、面积应变 (4D-GAPS) 及径向应变 (4D-GRPS) 参数指标分析左室各节段心肌运动功能,并应用 MCE 再灌注充盈曲线获得 A 值和 β 值分析各节段心肌血流灌注情况。 结果 在异常冠脉供血区,中度和重度狭窄组的 β 值和各应变值均低于对照组 (P<0.05),轻度狭窄组的 4D-GLPS、4D-GAPS 值低于对照组 (P<0.05)。单参数 ROC 曲线分析结果显示,4D-GLPS 和 4D-GAPS 诊断早期心肌损伤价值较高;多参数联合的 ROC 曲线分析结果显示,和单一技术相比,各应变值联合 β 值诊断中、重度冠脉狭窄节段的 AUC 较大 ,灵敏度及特异度相对较高。 结论 MCE 的再灌注参数 β 值和 4D-SI 技术参数 4D-GLPS、4D-GCPS、4D-GAPS 和 4D-GRPS 均可发现静息状态下 >75% 的冠脉狭窄引起的心肌缺血,其中 4D-GLPS、4D-GAPS 能够发现轻度狭窄组早期的心肌损伤改变,且两种技术结合诊断中、重度冠脉狭窄的价值明显高于仅应用单一技术。     

Myocardial perfusion imaging in coronary artery disease

Radionuclide myocardial perfusion imaging (MPI) can be used to demonstrate the presence of coronary heart disease and to risk stratify and guide management of patients with known disease. It has the ability to localize hemodynamically important coronary stenoses, and assess the extent and severity of coronary obstruction by the presence and extent of perfusion defects. A normal stress MPI indicates the absence of coronary obstruction and hence of clinically significant disease. Cardiac PET has the advantage from SPECT of higher spatial and temporal resolution, and a decreased radiation exposure to patients. Hybrid cardiac imaging combining SPECT or PET with CT data appears to offer superior diagnostic and prognostic information in patients with intermediate risk for CAD. A significant progress in better quantification of myocardial blood flow and coronary flow reserve has recently been seen. Also several studies have demonstrated that the combination of imaging apoptosis and matrix metalloproteinases production can help imaging vulnerable plaque and identifying the group of high-risk asymptomatic patients who will benefit most by an imaging procedure.     

Functional assessment of sequential coronary artery fistula and coronary artery stenosis with fractional flow reserve and stress adenosine myocardial perfusion imaging

Coronary artery fistula is an abnormal connection between one coronary artery to another coronary artery or cardiac chambers. The coronary artery fistula may cause significant shunting of blood and cause “pseudo-stenosis” or “steal phenomenon”. This will also accentuate pre-existing mild-moderate de novo coronary lesions with resultant greater pressure gradient difference across the lesions. Thus, fractional flow reserve can be a useful tool to guide intervention decision on the coronary artery fistula. There are very few published reports regarding the use of FFR to assess coronary artery fistula. In fact, there is no outcome data regarding the deferment of coronary artery fistula intervention when the FFR is not physiologically significant. This case highlighted the use of FFR to evaluate the functional significance of coronary fistula in the setting of ischemia evaluation and it was proven to be safe to defer intervention with good 3 year clinical outcome. Stress adenosine myocardial perfusion imaging correlated with the FFR result.     

Impact of hypertension on the accuracy of exercise stress myocardial perfusion imaging for the diagnosis of coronary artery disease

AIM—To compare the accuracy of exercise stress myocardial perfusion single photon emission computed tomography (SPECT) imaging for the diagnosis of coronary artery disease in patients with and without hypertension.
METHODS—A symptom limited bicycle exercise stress test in conjunction with 99m technetium sestamibi or tetrofosmin SPECT imaging was performed in 332 patients (mean (SD) age, 57 (10) years; 257 men, 75 women) without previous myocardial infarction who underwent coronary angiography. Of these, 137 (41%) had hypertension. Rest SPECT images were acquired 24 hours after the stress test. An abnormal scan was defined as one with reversible or fixed perfusion defects.
RESULTS—In hypertensive patients, myocardial perfusion abnormalities were detected in 79 of 102 patients with significant coronary artery disease and in nine of 35 patients without. In normotensive patients, myocardial perfusion abnormalities were detected in 104 of 138 patients with significant coronary artery disease and in 16 of 57 patients without. There were no differences between normotensive and hypertensive patients in sensitivity (77% (95% confidence interval (CI) 69% to 86%) v 75% (95% CI 68% to 83%)), specificity (74% (95% CI 60% to 89%) v 72% (95% CI 60% to 84%)), and accuracy (77% (95% CI 70% to 84%) v 74% (95% CI 68% to 80%)) of exercise SPECT for diagnosing coronary artery disease. The accuracy of SPECT was greater than electrocardiography, both in hypertensive patients (p = 0.005) and in normotensive patients (p = 0.0001). For the detection of coronary artery disease in individual vessels, sensitivity was 58% (95% CI 51% to 65%) v 57% (95% CI 51% to 64%), specificity was 86% (95% CI 82% to 90%) v 85% (95% CI 81% to 89%), and accuracy was 74% (95% CI 70% to 78%) v 74% (95% CI 70% to 78%) in patients with and without hypertension (NS).
CONCLUSIONS—In the usual clinical setting, the value of exercise myocardial perfusion scintigraphy for diagnosing coronary artery disease is not degraded by the presence of hypertension.


Keywords: hypertension; coronary artery disease; exercise stress test; myocardial perfusion     

Real-time perfusion adenosine stress echocardiography in the coronary care unit: a feasible bedside tool for predicting coronary artery stenosis in patients with acute coronary syndrome.

Myocardial contrast echocardiography using power modulation real-time perfusion (RTP) is an appealing method for bedside risk stratification of patients with acute coronary syndrome. In this study, we aimed to evaluate the accuracy in predicting significant coronary stenosis of a bedside RTP adenosine stress protocol in patients with acute coronary syndrome. METHODS: Prior to coronary angiography, 36 consecutive in-patients with acute coronary syndrome underwent a bedside adenosine stress echocardiography with RTP in the coronary care unit. Visual assessment of both perfusion and wall motion was made, comparing rest and hyperaemia images. Each segment was attributed to one of the three main coronary vessel areas. RESULTS: The sensitivity of predicting significant stenosis was 87, 83 and 81% for left anterior descending, circumflex and right posterior descending areas, respectively. Specificity was 69, 67 and 60%, respectively. The positive predictive values were 83, 79 and 74%, respectively. CONCLUSIONS: RTP using adenosine is a feasible bedside tool in predicting the area of significant coronary stenosis and could be helpful as a bedside decision-making tool in the clinical setting. More studies are required to assess the clinical value of RTP adenosine stress echocardiography.     

心脏腺苷负荷磁共振成像在冠心病早期诊断中的应用

目的:评价心脏腺苷负荷磁共振成像在冠心病早期诊断中的作用。方法: 选择临床无急性冠脉综合征,选择性冠状动脉造影（CAG）证实冠脉有不同程度狭窄的患者34例,根据CAG结果将患者分为3组,第1组管腔狭窄＞75%、第2组狭窄50%~75%以及第3组狭窄<50%。在3.0T磁共振成像仪上分别行静息和腺苷负荷磁共振心脏灌注扫描和延迟增强成像,对比分析不同状态下磁共振（MR）成像心肌灌注变化。结果: 在未发生急性冠脉综合征患者,静息磁共振心肌灌注成像显示心肌缺血主要表现为心肌灌注减少,总阳性率38%(13/34),不同冠状动脉狭窄组间无显著性差异。磁共振腺苷负荷试验可增加患者心肌灌注降低检测的阳性率［62%(21/34)］。统计结果显示,对于心肌缺血的检测,心脏磁共振腺苷负荷试验与静息心脏磁共振心肌灌注之间有显著性差异(P<0.01)。延迟扫描成像在34例患者中无延迟增强改变。结论: 腺苷负荷MR灌注成像可以显著提高心肌缺血诊断的阳性率,有助于冠心病的早期诊断。     

不同程度狭窄病变冠心病患者介入治疗后心肌灌注变化及临床意义

目的利用经冠状动脉超声心肌声学造影（MCE）比较单支血管不同程度狭窄病变冠心病患者经皮冠状动脉介入术（PCI）后心肌灌注的变化,并探讨其临床意义。方法62例进行PCI治疗的住院患者根据选择性冠状动脉造影结果,按血管狭窄程度分组:A组,血管狭窄75%95%;B组,血管狭窄>95%;C组,急性血管闭塞。PCI前及术后15 min进行经冠状动脉MCE,检测心肌灌注状况。其中,MCE有关定量参数分别为:造影剂峰值密度反映心肌血容量;峰值时间反映心肌灌注速度;曲线下面积反映心肌血流量。结果所有患者PC I后均达到TIMIⅢ级血流;A组术后心肌血流量较术前增加（P<0.05）;B组心肌血容量及血流量也较术前增加（P<0.05）;而C组心肌血容量、血流量及灌注速度较术前增加更显著（P<0.01）。结论不同狭窄程度病变冠心病患者,PCI后心肌灌注均得到不同程度改善,其中,以急性闭塞病变改善最明显,该类患者为PCI治疗的最大获益者。     

Complications of pharmacologic stress echocardiography in coronary artery disease

In the last few years, pharmacologic stress echocardiography is emerging as a promising diagnostic tool with a favorable cost/benefit ratio. Its main clinical applications include the assessment of coronary artery disease, the identification of viable myocardium, and risk stratification before major vascular surgery. However, cardiac (arrhythmic, ischemic, or hemodynamic) as well as noncardiac complications have been reported, so that a risk/benefit analysis is advisable in view of the extensive introduction of this technique in the clinical arena. The most popular pharmacologic agents employed for stress echocardiography are dipyridamole, do-butamine, and adenosine. A comparative analysis with exercise stress testing, the classical standard of reference of all ischemia-provoking tests, confirms that in terms of safety and tolerability pharmacologic stress echocardiography may be considered a good alternative in patients unable to exercise maximally. No appreciable difference among the safety profiles of the most common pharmacologic agents has been found, but a careful evaluation of the risk/benefit ratio is advisable for any stressor in the individual patient by considering the relative importance of the expected diagnostic contribution and the pharmacodynamic impact of the test. Finally, adequate training of the operator and monitoring of the patient during stress and recovery are essential for getting optimal safety conditions.     

The grade of worsening of regional function during dobutamine stress echocardiography predicts the extent of myocardial perfusion abnormalities

AIM—To evaluate the angiographic, myocardial perfusion, and wall motion abnormalities in patients with severe compared with mild worsening of regional function during dobutamine stress echocardiography (DSE) for evaluation of myocardial ischaemia.
METHODS—147 patients with significant coronary artery disease and new or worsening wall motion abnormalities during DSE were enrolled. Left ventricular function was evaluated using a 16 segment/4 grade score model where 1 = normal and 4 = dyskinesis. Simultaneous sestamibi SPECT myocardial perfusion imaging was performed in all patients.
RESULTS—Severe worsening of regional function (an increase in wall motion score of two grades or more in  1 segment) was detected in 37 patients, while 110 patients had mild worsening (an increase in wall motion score of no more than one grade in  1 segment). Patients with severe worsening of regional function had more stenotic coronary arteries (2.31 (0.8) v 1.97 (0.8) (mean (SD)) (p <0.05), a higher prevalence of left anterior descending coronary artery disease (95% v 73%) (p < 0.05), a higher resting wall motion score index (1.71 (0.42) v 1.51 (0.40) (p = 0.01), and more stress perfusion defects (3.8 (1.5) v 2.8 (1.5) (p < 0.001) compared with patients with mild worsening. Multivariate analysis identified the number of stress perfusion defects (p < 0.005, χ² = 8.8) and the number of ischaemic segments on echocardiography (p < 0.05, χ² = 4.3) as independent variables associated with severe worsening of regional function.
CONCLUSIONS—The grade of worsening of regional function during DSE predicts the underlying extent of myocardial perfusion abnormalities. The occurrence of severe worsening of regional function is associated with variables known to predict worse prognosis in patients with coronary artery disease.


Keywords: coronary artery disease; myocardial perfusion; ventricular function; echocardiography     

Physiologic assessment of left anterior descending coronary artery stenosis by quantitative intravenous myocardial contrast echocardiography in humans: comparison with exercise single-photon emission computed tomography

OBJECTIVE: To clarify the potential of quantitative intravenous myocardial contrast echocardiography (MCE) for physiologic assessment of the left anterior descending artery (LAD) stenosis. METHODS: We studied 38 patients with suspected coronary artery disease. MCE was performed by continuous infusion of Levovist and intermittent ultrasonic exposure. Images were obtained from the apical four-chamber view at rest and after dipyridamole infusion. The background-subtracted intensity versus pulsing interval plots were fitted to an exponential function,Y=A(1 e-ss), to obtain the plateau level (A) and rate of rise (ss) of background-subtracted intensity both at rest and after dipyridamole infusion. We compared the results with those of exercise thallium-201 single-photon emission computed tomography (SPECT). RESULTS: Of the 38 patients, 18 patients exhibited redistribution in the LAD territories with SPECT (group A), although 20 did not (group B). The ss reserve (DIP/rest) in group A was significantly lower than those in group B (0.8 +/- 0.5 versus 2.0 +/- 1.1, P < 0.001), while the A reserve did not differ between the two groups (1.2 +/- 0.6 versus 1.0 +/- 0.5, P = NS). The ss reserve <1.1, which was the optimal cutoff value, provided sensitivity of 79% and specificity of 84% for the presence of redistribution in SPECT. CONCLUSIONS: Quantitative intravenous MCE allows us to estimate physiologic severity of the LAD stenosis in the clinical setting.     

Detection of coronary artery disease with perfusion stress echocardiography using a novel ultrasound imaging agent: two Phase 3 international trials in comparison with radionuclide perfusion imaging

Aims: To determine if perfusion stress echocardiography (PSE) withImagify^TM (perflubutane polymer microspheres) is comparableto stress perfusion imaging using ^99mTc single photon emissioncomputed tomography (SPECT) for coronary artery disease (CAD)detection. PSE is a novel technique for evaluating myocardialperfusion. RAMP (real-time assessment of myocardial perfusion)-1and -2 were international, Phase 3 trials that evaluated theability of PSE with Imagify, to detect CAD. Methods and results: Chronic, stable, chest pain patients (n = 662) underwent ImagifyPSE and gated SPECT imaging at rest and during dipyridamolestress. Independent blinded cardiologists [three PSE readersper trial, and four SPECT readers (one for RAMP-1, three forRAMP-2)] interpreted images. CAD was defined by quantitativecoronary angiography or 90-day outcome with clinical review.Accuracy, sensitivity, and specificity were evaluated usingnon-inferiority analysis (one-sided alpha = 0.025) comparedwith SPECT. SPECT results for RAMP-1 and -2 were: accuracy (70%,67%), sensitivity (78%, 61%), and specificity (64%, 76%). Accuracyof all six PSE readers was non-inferior to SPECT (66–71%,P 0.004). Four demonstrated non-inferior sensitivity (68–77%,P 0.002), three demonstrated non-inferior specificity (72–88%,P 0.013). Three PSE readers (RAMP-2) were superior for sensitivity.Two PSE readers (RAMP-1) were superior for specificity. Areaunder the multi-reader receiver operating characteristics curve(0.72) was equal for both modalities. Majority of adverse eventsfollowed dipyridamole dosing, and were mild, transient, andrequired no treatment. Conclusions: Imagify PSE was well-tolerated. Its diagnostic performance inchest pain patients is comparable with SPECT perfusion imaging.     

等负荷运动心电图、二维超声心动图及心肌灌注断层显像对冠心病的诊断价值

对28例冠状动脉造影阳性和18例冠状动脉造影阴性患者进行等负荷运动心电图(运动ECG)、二维超声心动图(2-DE)及心肌灌注断层显像(SPECT)试验。结果表明:单项负荷试验以SPECT敏感性最高、2-DE的特异性最高,而运动ECG的敏感性及特异性则介于二者之间;联合负荷试验三项均阳性诊断冠心病的可靠性最大,二项阳性有诊断冠心病的可能.一项阳性诊断冠心病的可能性小,阳性意义需结合临床考虑,三项阴性者可排除冠心病。认为三项等负荷试验联合判定是筛选和诊断冠心病的准确、可靠的无创性检查方法。     

Radiation dose difference between state of the art myocardial perfusion scintigraphy and computed tomography coronary angiography in patients undergoing evaluation for suspected coronary artery disease

Minimisation of radiation exposure with cardiac imaging reduces the potential of secondary side effects. Radiation exposure from myocardial perfusion scintigraphy and computed tomography coronary angiography (CTCA) was compared. Overall doses were low with both modalities. Doses were lower in the CTCA group, but by only a small difference of 1.1 mSv. Radiation exposure should not be the primary consideration when choosing between these two modalities.     

腺苷负荷超声心动图诊断冠心病的临床评价

目的:以冠状动脉造影(CAG)为金标准,评价腺苷负荷超声心动图(ASE)试验诊断冠心病(CHD)的敏感性和特异性.方法:40例临床疑诊CHD患者,分别静脉注射腺苷(140 μg·kg-1·min-1)6 min(总剂量为0.8 mg/kg).出现节段性室壁运动异常为阳性.所有患者1周内行CAG检查.结果:ASE诊断CHD的敏感性为82.6%,特异性为88.2%,准确性为85.0%;诊断单支、双支和3支冠状动脉病变的敏感性分别为75.0%,85.7%,100%,且不良反应少.结论: ASE诊断CHD安全可靠.     

A method of detecting and quantifying severity of myocardial perfusion defects with intravenous ultrasound contrast and breath holding during stress echocardiography

Although breath holding is commonly used to improve and maintain image quality during stress echocardiography, its effects on the qualitative and quantitative analysis of myocardial contrast enhancement (MCE) following intravenously injected microbubbles is unknown. The purpose of this study was to determine how breath holding affects MCE following either an intravenous bolus or continuous infusion of perfluorocarbon containing microbubbles. In 48 patients, intravenous Optison was given at peak dobutamine stress to assess myocardial perfusion. The degree of myocardial opacification was assessed immediately following a breath hold in inspiration (BH(ini)), at the end of a breath hold (BH(term)), and following expiration and a subsequent second breath hold (BH(reinsp)). Pulmonary venous time velocity integrals were recorded during these different phases as well. Eleven patients had quantitative coronary angiography. Mean duration of the breath hold was 7 +/- 1 seconds. Pulmonary venous return fell by 29% +/- 18% at BH(term) (P < 0.001). There was complete disappearance of MCE at BH(term) in 27 of 35 bolus injection patients at peak stress, and no return of MCE following flash destruction during breath holding in 11 of 13 patients receiving continuous infusions. BH(reinsp) resulted in a boluslike return of contrast, with a transient, bright MCE in 44 of 48 patients, and a time intensity plot that resembled a gamma variate function. Perfusion defects were visualized in 25 patients during BH(ini) and 28 patients during BH(reinsp). Coronary artery territory agreement between perfusion assessed during BH(ini) and BH(reinsp) and quantitative coronary angiography was 76% and 81%, respectively.