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Myocardial Perfusion (myocardial + perfusion)

Distribution by Scientific Domains
Medical Sciences96%
Distribution within Medical Sciences
Cardiovascular Disease58%
Radiology & Imaging13%
5 Other Subdomains29%

Terms modified by Myocardial Perfusion

  • myocardial perfusion imaging
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  • myocardial perfusion mri
    		•
  • myocardial perfusion scintigraphy
    		•

    Selected Abstracts

    Myocardial Perfusion As Assessed by Positron Emission Tomography During Long-Term Mechanical Circulatory Support

    CONGESTIVE HEART FAILURE, Issue 2 2006
    George V. Letsou MD
    Although mechanical circulatory support (MCS) can improve myocardial function in patients with advanced heart failure, its effects on relative myocardial perfusion are unclear. Using positron emission tomographic imaging techniques, the authors assessed relative myocardial perfusion in patients with ischemic or idiopathic cardiomyopathy who were receiving chronic MCS with a left ventricular assist device (pulsatile HeartMate [n=2] [Thoratec Corporation, Pleasanton, CA] or nonpulsatile Jarvik 2000 [n=4] [Jarvik Heart, Inc., New York, NY]). Relative myocardial perfusion was compared at lower and higher levels of MCS (50 vs. 100,110 ejections/min for the HeartMate and 8000 vs. 12,000 rpm for the Jarvik 2000). The size and severity of perfusion defects at rest and after dipyridamole stress were measured objectively and subjectively by computer algorithms and visual inspection, respectively. Relative myocardial perfusion increased >5% from baseline in only one of six patients when MCS was increased. No change in relative myocardial perfusion of >5% was seen in any of the other five patients, even after subsequent dipyridamole stress positron emission tomographic imaging. These pilot study findings suggest that the decreased metabolic requirements induced by ventricular unloading correspondingly decreased blood flow requirements to physiologically inactive myocardium. [source]

    Design of an Ultrasound Contrast Agent for Myocardial Perfusion

    ECHOCARDIOGRAPHY, Issue 2000
    Michel Schneider Ph.D.
    Myocardial contrast echography (MCE) has been a major research objective in cardiovascular ultrasound for almost two decades. The design of a contrast agent fulfilling the needs of MCE requires taking into consideration a number of points: a basic decision has to be made whether a deposit agent or a free-flowing agent would be more appropriate and whether an agent active at low/medium mechanical index (MI) is preferable to an agent active only at high MI; only a small percentage of the cardiac output enters the coronary microcirculation, which means that highly sensitive bubble detection methods, such as harmonic imaging or pulse inversion, are needed; the low velocity of blood in the microcirculation that leads to extensive bubble destruction during imaging means that intermittent imaging and/or an agent active at low MI is (are) required; the duration of the contrast effect must be sufficient to allow a complete examination and is affected by the rate of contrast administration; the performance of the contrast agent should not be equipment-dependent. The ultimate goal in MCE is to be able to quantify blood flow in the various segments to determine if adequate oxygenation is achieved. Ultrasound-mediated bubble destruction followed by the measurement of bubble replenishment kinetics opens new perspectives for quantification. SonoVue is a free-flowing ultrasound contrast agent made of sulphur hexafluoride microbubbles stabilized by a highly elastic phospholipid monolayer. SonoVue is able to produce myocardial opacification at a wide range of acoustic pressures and in particular at Mis as low as 0.1. Its performance is not equipment-dependent. Good results for myocardial opacification have been observed in all animal species tested (dogs, minipigs, rabbits), using continuous as well as intermittent imaging. Trials are in progress to demonstrate the clinical utility of SonoVue for rest and stress perfusion studies, in particular for the diagnosis of CAD, the detection of myocardial infarction, the assessment of the success of interventions and myocardial viability, and the detection of hibernating myocardium. [source]

    Surgery for Cardiac Valves and Aortic Root Without Cardioplegic Arrest ("Beating Heart"): Experience with a New Method of Myocardial Perfusion

    JOURNAL OF CARDIAC SURGERY, Issue 6 2007
    Tomas A. Salerno M.D.
    Similarly, beating heart mitral valve surgery via the trans-septal approach with the aorta unclamped, is a novel technique. We, herein, report a series of 346 patients with a variety of cardiac pathologies who were operated upon utilizing a new modality of myocardial perfusion. Among this group of patients, there were 55 patients who were diagnosed with endocarditis of one or more valves. These patients were excluded from this series of patients. Mean age was 59 ± 12, and there were 196 (67.3%) males and 95 (32.7%) females. There were six aortic root procedures, 90 mitral valve replacements (MVR), 46 mitral valve repairs, 20 MVR+ coronary artery bypass grafting (CABG), 28 tricuspid valve repairs, 106 aortic valve replacements (AVR), 17 AVR+CABG, and 8 AVR/MVR. Crude mortality for the group was 20 of 291 (6.8%). Intra-aortic balloon pump utilization at time of weaning from cardiopulmonary bypass was 6/291 (2.06%), and re-operation for bleeding was needed in 12 of 291 (4.1%) patients. Postoperative stroke occurred in 4 of 291 (1.3%) patients. In these patients, the clinical diagnosis of stroke was made prior to surgery. This initial experience with this new method of myocardial perfusion indicates that results are at least comparable, if not superior, to conventional techniques utilizing intermittent cold blood cardioplegia. [source]

    Proximal Coronary Hemodynamic Changes Evaluated by Intracardiac Echocardiography during Myocardial Ischemia and Reperfusion in a Canine Model

    ECHOCARDIOGRAPHY, Issue 3 2008
    Beibei Han M.D.
    Background: The purpose of this study was to assess whether the dynamic changes in coronary flow velocity and coronary flow velocity reserve (CFVR) by intracardiac echocardiography (ICE) within proximal coronary arteries are related to myocardial perfusion status and infarct size in a myocardial ischemia-reperfusion injury model. Methods: In 14 dogs, left anterior descending coronary artery (LAD) was ligated for 2 hours followed by 2 hours reperfusion. Coronary flow velocity was obtained by ICE within coronary arteries at baseline, and at the end of both occlusion and reperfusion period. The CFVR was calculated as the ratio of hyperemic to resting peak diastolic velocity (PDV). Myocardial perfusion was evaluated by real time myocardial contrast echocardiography (MCE). The infarct area was detected by triphenyltetrazolium chloride (TTC) staining and expressed as the percentage of the whole left ventricular (LV) area. Results: CFVR significantly decreased both in proximal LAD and left circumflex (LCx) artery at the end of occlusion, and did not recover at the end of reperfusion. However, no significant difference in flow parameters was observed between dogs with myocardial perfusion defect and those without. CFVR in LAD at the end of reperfusion did not correlate with the infarct size (r =,0.182, P = NS) either. Conclusions: Decreased CFVR detected by ICE occurs both in ischemic and in nonischemic proximal arteries during myocardial ischemia and early stage of reperfusion. This change in CFVR has poor correlation with the extent of microvascular impairment and cannot be used to predict infarct size. [source]

    Myocardial perfusion defects in Bartter and Gitelman syndromes

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2008
    R. Scognamiglio
    ABSTRACT Background, Normotensive hypokalaemic tubulopathies (Bartter and Gitelman syndromes (BS/GS)) are genetic diseases that are considered benign. However, QT prolongation, left ventricular dysfunction and reduction of cardiac index upon exercise leading to arrhythmias and sudden cardiac death have been reported in these patients. Hence, we aimed to verifying whether an isometric exercise could represent a useful tool for the identification of patients at risk for future cardiac events. Patients and methods, Myocardial function (MF) and perfusion, evaluated as myocardial blood flow (MBF) of 10 BS/GS patients and 10 healthy controls, were investigated at rest and during isometric exercise. MF and MBF were evaluated using quantitative two-dimensional and myocardial contrast echocardiography. Results, BS/GS patients had normal baseline MF and MBF. During exercise in BS/GS patients, corrected QT (QTc) was prolonged to peak value of 494 ± 9·1 ms (P < 0·001). In controls, MF increased from resting to peak exercise (left ventricular ejection fraction: 65 ± 4% to 78 ± 5%, P < 0·003) while in seven BS/GS patients (Group 1) it declined (64 ± 5% to 43 ± 9%, P < 0·001). Myocardial perfusion increased upon exercise in controls as shown by changes of its markers: , (a measure of myocardial flow velocity; 0·89 ± 0·12 vs. 0·99 ± 0·12, P < 0·001) and myocardial blood volume (14·4 ± 2 vs. 20·2 ± 0·25, P < 0·001), while in Group 1 BS/GS it decreased (0·87 ± 0·15 vs. 0·67 ± 0·15, P < 0·001; and 14·5 ± 1·9 vs. 8·3 ± 0·22, P < 0·001, respectively). Conclusions, Our results document for the first time that exercise induce coronary microvascular and myocardial defects in BS/GS patients. Therefore, this may challenge the idea that BS/GS are benign diseases. In addition, the diagnostic approach to these syndromes should include an in-depth cardiac assessment in order to identify patients at higher risk. [source]

    Quantitative analysis of first-pass contrast-enhanced myocardial perfusion MRI using a patlak plot method and blood saturation correction

    MAGNETIC RESONANCE IN MEDICINE, Issue 2 2009
    Takashi Ichihara
    Abstract The objectives of this study were to develop a method for quantifying myocardial K1 and blood flow (MBF) with minimal operator interaction by using a Patlak plot method and to compare the MBF obtained by perfusion MRI with that from coronary sinus blood flow in the resting state. A method that can correct for the nonlinearity of the blood time,signal intensity curve on perfusion MR images was developed. Myocardial perfusion MR images were acquired with a saturation-recovery balanced turbo field-echo sequence in 10 patients. Coronary sinus blood flow was determined by phase-contrast cine MRI, and the average MBF was calculated as coronary sinus blood flow divided by left ventricular (LV) mass obtained by cine MRI. Patlak plot analysis was performed using the saturation-corrected blood time,signal intensity curve as an input function and the regional myocardial time,signal intensity curve as an output function. The mean MBF obtained by perfusion MRI was 86 ± 25 ml/min/100 g, showing good agreement with MBF calculated from coronary sinus blood flow (89 ± 30 ml/min/100 g, r = 0.74). The mean coefficient of variation for measuring regional MBF in 16 LV myocardial segments was 0.11. The current method using Patlak plot permits quantification of MBF with operator interaction limited to tracing the LV wall contours, registration, and time delays. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source]

    Effect of Chronic Sustained-Release Dipyridamole on Myocardial Blood Flow and Left Ventricular Function in Patients With Ischemic Cardiomyopathy

    CONGESTIVE HEART FAILURE, Issue 3 2007
    Mateen Akhtar MD
    Dipyridamole increases adenosine levels and augments coronary collateralization in patients with coronary ischemia. This pilot study tested whether a 6-month course of sustained-release dipyridamole/aspirin improves coronary flow reserve and left ventricular systolic function in patients with ischemic cardiomyopathy. Six outpatients with coronary artery disease and left ventricular ejection fraction (LVEF) <40% were treated with sustained-release dipyridamole 200 mg/aspirin 25 mg twice daily for 6 months. Myocardial function and perfusion, including coronary sinus flow at rest and during intravenous dipyridamole-induced hyperemia, were measured using velocity-encoded cine magnetic resonance stress perfusion studies at baseline, 3 months, and 6 months. There was no change in heart failure or angina class at 6 months. LVEF increased by 39%±64% (31.0%±13.3% at baseline vs 38.3%±10.7% at 6 months; P=.01), hyperemic coronary sinus flow increased more than 2-fold (219.6±121.3 mL/min vs 509.4±349.3 mL/min; P=.01), and stress-induced relative myocardial perfusion increased by 35%±13% (9.4%±3.4% vs 13.9%±8.5%; P=.004). Sustained-release dipyridamole improved hyperemic myocardial blood flow and left ventricular systolic function in patients with ischemic cardiomyopathy. [source]

    Myocardial Perfusion As Assessed by Positron Emission Tomography During Long-Term Mechanical Circulatory Support

    CONGESTIVE HEART FAILURE, Issue 2 2006
    George V. Letsou MD
    Although mechanical circulatory support (MCS) can improve myocardial function in patients with advanced heart failure, its effects on relative myocardial perfusion are unclear. Using positron emission tomographic imaging techniques, the authors assessed relative myocardial perfusion in patients with ischemic or idiopathic cardiomyopathy who were receiving chronic MCS with a left ventricular assist device (pulsatile HeartMate [n=2] [Thoratec Corporation, Pleasanton, CA] or nonpulsatile Jarvik 2000 [n=4] [Jarvik Heart, Inc., New York, NY]). Relative myocardial perfusion was compared at lower and higher levels of MCS (50 vs. 100,110 ejections/min for the HeartMate and 8000 vs. 12,000 rpm for the Jarvik 2000). The size and severity of perfusion defects at rest and after dipyridamole stress were measured objectively and subjectively by computer algorithms and visual inspection, respectively. Relative myocardial perfusion increased >5% from baseline in only one of six patients when MCS was increased. No change in relative myocardial perfusion of >5% was seen in any of the other five patients, even after subsequent dipyridamole stress positron emission tomographic imaging. These pilot study findings suggest that the decreased metabolic requirements induced by ventricular unloading correspondingly decreased blood flow requirements to physiologically inactive myocardium. [source]

    Assessment of the Vascularity of a Left Atrial Mass Using Myocardial Perfusion Contrast Echocardiography

    ECHOCARDIOGRAPHY, Issue 5 2008
    Sahar S. Abdelmoneim M.D. M.Sc.
    Emerging applications of myocardial contrast echocardiography (MCE) include the evaluation of myocardial perfusion, the improvement of the definition of intracavitary structures, and evaluation of the relative perfusion of a cardiac mass. We present a case of a patient that was found incidentally to have a cardiac mass on transthoracic echocardiography. MCE was used to evaluate the vascularity of the mass. This case is compared with another patient with a left atrial thrombus, which represents an "avascular" cardiac mass by MCE. [source]

    Diagnostic and Prognostic Value of Myocardial Perfusion Imaging in Patients with Known or Suspected Stable Coronary Artery Disease

    ECHOCARDIOGRAPHY, Issue 6 2000
    Aman M. Amanullah M.D., Ph.D.
    Coronary artery disease is the leading cause of complications and death in the United States and other Western countries, and stress myocardial perfusion study is an important component of the clinical evaluation, stratification, and management. This imaging technique is a well-established modality and has been widely used for the past three decades. New quantitative techniques for the assessment of ventricular function using quantitative gated single-photon emission computed tomography in addition to myocardial perfusion will potentially enhance the role of nuclear cardiology in the management of these patients. This review summarizes the current knowledge of the diagnostic and prognostic uses of stress myocardial perfusion imaging using exercise and pharmacological stress in patients with stable coronary artery disease. [source]

    Contrast Echocardiography: Clinical Utility

    ECHOCARDIOGRAPHY, Issue 2000
    Gerald Maurer M.D.
    This article reviews the advances made by the echocardiography contrast agents from their first appearance in the early 1970s with homemade preparations up to the new generation of transpul-monary contrast agents made of small microbubbles capable of transversing the lung's capillary bed. The great progress in contrast agent development has kept pace with the progress made by echocar-diographic equipment, thus making the study of myocardial perfusion in the clinical settings a near-future reality. This article also discusses the medical need that myocardial contrast echo has the potential to satisfy. [source]

    Role of Intravenous Ultrasound Contrast in Stress Echocardiography

    ECHOCARDIOGRAPHY, Issue 1 2000
    F.A.C.C., THOMAS R. PORTER M.D.
    Intravenous newer generation perfluorocarbon containing microbubbles have been shown to enhance endocardial borders, especially during harmonic imaging. Although this significantly improves the detection of wall-motion abnormalities during stress echocardiography, intermittent imaging consistently results in myocardial contrast following intravenous infusions or injections of perfluorocarbon microbubbles. Detection of myocardial perfusion abnormalities during both exercise and pharmacologic stress echocardiography appears to be feasible clinically with either intravenous injections or continuous infusions of microbubbles using intermittent harmonic imaging. Accelerated intermittent harmonic imaging allows one to rapidly acquire both myocardial perfusion and wall motion during exercise and dobutamine stress echocardiography. (ECHOCARDIOGRAPHY, Volume 17, January 2000) [source]

    Surgery for Cardiac Valves and Aortic Root Without Cardioplegic Arrest ("Beating Heart"): Experience with a New Method of Myocardial Perfusion

    JOURNAL OF CARDIAC SURGERY, Issue 6 2007
    Tomas A. Salerno M.D.
    Similarly, beating heart mitral valve surgery via the trans-septal approach with the aorta unclamped, is a novel technique. We, herein, report a series of 346 patients with a variety of cardiac pathologies who were operated upon utilizing a new modality of myocardial perfusion. Among this group of patients, there were 55 patients who were diagnosed with endocarditis of one or more valves. These patients were excluded from this series of patients. Mean age was 59 ± 12, and there were 196 (67.3%) males and 95 (32.7%) females. There were six aortic root procedures, 90 mitral valve replacements (MVR), 46 mitral valve repairs, 20 MVR+ coronary artery bypass grafting (CABG), 28 tricuspid valve repairs, 106 aortic valve replacements (AVR), 17 AVR+CABG, and 8 AVR/MVR. Crude mortality for the group was 20 of 291 (6.8%). Intra-aortic balloon pump utilization at time of weaning from cardiopulmonary bypass was 6/291 (2.06%), and re-operation for bleeding was needed in 12 of 291 (4.1%) patients. Postoperative stroke occurred in 4 of 291 (1.3%) patients. In these patients, the clinical diagnosis of stroke was made prior to surgery. This initial experience with this new method of myocardial perfusion indicates that results are at least comparable, if not superior, to conventional techniques utilizing intermittent cold blood cardioplegia. [source]

    Improved myocardial perfusion in chronic diabetic mice by the up-regulation of pLKB1 and AMPK signaling

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2010
    Claudia Kusmic
    Abstract Previous studies related impaired myocardial microcirculation in diabetes to oxidative stress and endothelial dysfunction. Thus, this study was aimed to determine the effect of up-regulating pAMPK-pAKT signaling on coronary microvascular reactivity in the isolated heart of diabetic mice. We measured coronary resistance in wild-type and streptozotocin (STZ)-treated mice, during perfusion pressure changes. Glucose, insulin, and adiponectin levels in plasma and superoxide formation, NOx levels and heme oxygenase (HO) activity in myocardial tissue were determined. In addition, the expression of HO-1, 3-nitrotyrosine, pLKB1, pAMPK, pAKT, and peNOS proteins in control and diabetic hearts were measured. Coronary response to changes in perfusion pressure diverged from control in a time-dependent manner following STZ administration. The responses observed at 28 weeks of diabetes (the maximum time examined) were mimicked by L-NAME administration to control animals and were associated with a decrease in serum adiponectin and myocardial pLKB1, pAMPK, pAKT, and pGSK-3 expression. Cobalt protoporphyrin treatment to induce HO-1 expression reversed the microvascular reactivity seen in diabetes towards that of controls. Up-regulation of HO-1 was associated with an increase in adiponectin, pLKB1, pAKT, pAMPK, pGSK-3, and peNOS levels and a decrease in myocardial superoxide and 3-nitrotyrosine levels. In the present study we describe the time course of microvascular functional changes during the development of diabetes and the existence of a unique relationship between the levels of serum adiponectin, pLKB1, pAKT, and pAMPK activation in diabetic hearts. The restoration of microvascular function suggests a new therapeutic approach to even advanced cardiac microvascular derangement in diabetes. J. Cell. Biochem. 109: 1033,1044, 2010. © 2010 Wiley-Liss, Inc. [source]

    Clinical Experience with a Novel Intracoronary Perfusion Catheter to Treat No-Reflow Phenomenon in Acute Coronary Syndromes

    JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2010
    GABRIEL MALUENDA M.D.
    Background:,The no-reflow phenomenon is an often seen complication in patients presenting with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). This event is associated with poor prognosis and poses a therapeutic challenge. Methods:,This retrospective study cohort was composed of 30 patients who presented with ACS between September 2007 and April 2009, and developed no-reflow during subsequent PCI. The primary end-point was defined as normal Thrombolysis In Myocardial Infarction (TIMI) 3 flow with myocardial blush grade (MBG) ,2 or an increase in TIMI flow by ,2 grades with a MBG ,2 after intracoronary drug infusion via the ClearWay (CW) RX perfusion catheter. Results:,The population presented with a relatively high prevalence of cardiovascular risk factors. ST-elevation myocardial infarction was the most common presentation (60.0%), while 20% of the patients presented with cardiogenic shock. After intracoronary infusion of nicardipine or nitroprusside using the CW catheter, TIMI flow improved from the baseline in 19 cases (63.3%, P < 0.001), and 16 patients (53.3%, P < 0.001) achieved normal coronary flow at the end of the procedure. The rate of in-hospital death was 6.7% (2 cases). No clinical differences were noted between those patients who successfully achieved normal coronary flow and those with persistent no-reflow. Conclusion:,The infusion of intracoronary drugs using the novel perfusion CW RX catheter seems to be safe and could help to improve myocardial perfusion in a selected group of patients presenting with ACS who developed no-reflow during PCI. (J Interven Cardiol 2010;23:109-113) [source]

    Comparison of dual to single contrast bolus magnetic resonance myocardial perfusion imaging for detection of significant coronary artery disease

    JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2010
    Jan G.J. Groothuis MD
    Abstract Purpose: To investigate the incremental diagnostic value of dual-bolus over single-contrast-bolus first pass magnetic resonance myocardial perfusion imaging (MR-MPI) for detection of significant coronary artery disease (CAD). Materials and Methods: Patients (n = 49) with suspected CAD underwent first pass adenosine stress and rest MR-MPI and invasive coronary angiography (CA). Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) was injected with a prebolus (1 mL) and a large bolus (0.1 mmol/kg). For the single-bolus technique, the arterial input function (AIF) was obtained from the large-contrast bolus. For the dual-bolus technique, the AIF was reconstructed from the prebolus. Absolute myocardial perfusion was calculated by Fermi-model constrained deconvolution. Receiver operating characteristic (ROC) analysis was used to investigate diagnostic accuracy of MR myocardial perfusion imaging for detection of significant CAD on CA at vessel-based analysis. Results: The area under the curve (AUC) of the minimal stress perfusion value for the detection of significant CAD using the single-bolus and dual-bolus technique was 0.85 ± 0.04 (95% confidence interval [CI], 0.77,0.93) and 0.77 ± 0.05 (95% CI, 0.67,0.86), respectively. Conclusion: In this study the dual-bolus technique had no incremental diagnostic value over single-bolus technique for detection of significant CAD with the used contrast concentrations. J. Magn. Reson. Imaging 2010;32:88,93. © 2010 Wiley-Liss, Inc. [source]

    Fast mapping of myocardial blood flow with MR first-pass perfusion imaging

    MAGNETIC RESONANCE IN MEDICINE, Issue 6 2008
    Thomas A. Goldstein
    Abstract Accurate and fast quantification of myocardial blood flow (MBF) with MR first-pass perfusion imaging techniques on a pixel-by-pixel basis remains difficult due to relatively long calculation times and noise-sensitive algorithms. In this study, Zierler's central volume principle was used to develop an algorithm for the calculation of MBF with few assumptions on the shapes of residue curves. Simulation was performed to evaluate the accuracy of this algorithm in the determination of MBF. To examine our algorithm in vivo, studies were performed in nine normal dogs. Two first-pass perfusion imaging sessions were performed with the administration of the intravascular contrast agent Gadomer at rest and during dipyridamole-induced vasodilation. Radiolabeled microspheres were injected to measure MBF at the same time. MBF measurements in dogs using MR methods correlated well with the microsphere measurements (R2 = 0.96, slope = 0.9), demonstrating a fair accuracy in the perfusion measurements at rest and during the vasodilation stress. In addition to its accuracy, this method can also be optimized to run relatively fast, providing potential for fast and accurate myocardial perfusion mapping in a clinical setting. Magn Reson Med, 2008. © 2008 Wiley-Liss, Inc. [source]

    Perfusion MRI with radial acquisition for arterial input function assessment,

    MAGNETIC RESONANCE IN MEDICINE, Issue 5 2007
    Eugene G. Kholmovski
    Abstract Quantification of myocardial perfusion critically depends on accurate arterial input function (AIF) and tissue enhancement curves (TECs). Except at low doses, the AIF is inaccurate because of the long saturation recovery time (SRT) of the pulse sequence. The choice of dose and SRT involves a trade-off between the accuracy of the AIF and the signal-to-noise ratio (SNR) of the TEC. Recent methods to resolve this trade-off are based on the acquisition of two data sets: one to accurately estimate the AIF, and one to find the high-SNR TEC. With radial k -space sampling, a set of images with varied SRTs can be reconstructed from the same data set, allowing an accurate assessment of the AIF and TECs, and their conversion to contrast agent (CA) concentration. This study demonstrates the feasibility of using a radial acquisition for quantitative myocardial perfusion imaging. Magn Reson Med 57:821,827, 2007. © 2007 Wiley-Liss, Inc. [source]

    Fluid resuscitation from severe hemorrhagic shock using diaspirin cross-linked hemoglobin fails to improve pancreatic and renal perfusion

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2004
    A. Pape
    Background:, Fluid resuscitation from hemorrhagic shock is intended to abolish microcirculatory disorders and to restore adequate tissue oxygenation. Diaspirin cross-linked hemoglobin (DCLHb) is a hemoglobin-based oxygen carrier (HBOC) with vasoconstrictive properties. Therefore, fluid resuscitation from severe hemorrhagic shock using DCLHb was expected to improve perfusion pressure and tissue perfusion of kidneys and pancreas. Methods:, In 20 anesthetized domestic pigs with an experimentally induced coronary stenosis, shock (mean arterial pressure 45 mmHg) was induced by controlled withdrawal of blood and maintained for 60 min. Fluid resuscitation (replacement of the plasma volume withdrawn during hemorrhage) was performed with either 10% DCLHb (DCLHb group, n = 10) or 8% human serum albumin (HSA) oncotically matched to DCLHb (HSA group, n = 10). Completion of resuscitation was followed by a 60-min observation period. Regional blood flow to the kidneys and the pancreas was measured by use of the radioactive microspheres method at baseline, after shock and 60 min after fluid resuscitation. Results:, All animals (10/10) resuscitated with DCLHb survived the 60-min observation period, while 5/10 control animals died within 20 min due to persisting subendocardial ischemia. In contrast to HSA survivors, pancreas and kidneys of DCLHb-treated animals revealed lower total and regional organ perfusion and regional oxygen delivery. Renal and pancreatic blood flow heterogeneity was higher in the DCLHb group. Conclusion:, DCLHb-induced vasoconstriction afforded superior myocardial perfusion, but impaired regional perfusion of the kidneys and the pancreas. [source]

    Noninvasive Imaging of Angiogenesis Inhibition Following Nitric Oxide Synthase Blockade in the Ischemic Rat Heart in Vivo

    MICROCIRCULATION, Issue 4 2005
    CHRISTIANE WALLER MD
    ABSTRACT Objective: Nitric oxide synthase inhibition has anti-angiogenic properties. Magnetic resonance (MR) imaging was used to image the functional significance of these microvascular changes in a rat model of chronic ischemic myocardium in vivo. Methods: The authors quantitatively determined myocardial perfusion and regional blood volume, left ventricular geometry, and function using MR imaging. Animals received either L-NAME + hydralazine or no treatment and were investigated 1 and 2 weeks after induction of coronary artery stenosis or sham operation at rest and during vasodilatation. Double-labeling immunohistochemistry was used to visualize angiogenesis and to compare with data obtained by MR imaging. Results: Left ventricular mass and end-diastolic volumes were comparable in both groups 2 weeks after treatment. However, basal and maximum perfusion in animals with L -NAME + hydralazine treatment were reduced compared to animals not treated (p < .05). Basal regional blood volume remained constant in all groups, whereas maximum regional blood volume was reduced by L -NAME + hydralazine (p < .05). Endothelial cell proliferation, a direct marker for angiogenesis, was reduced by L -NAME + hydralazine (p < .01). Conclusions: MR imaging allows noninvasive quantification of functional microcirculation and angiogenesis in the rat heart in vivo. Nitric oxide synthase blockade results in changes in functional microcirculation and in an inhibition of angiogenesis in both ischemic and nonischemic myocardial tissue. [source]

    Strain-Encoded Cardiac Magnetic Resonance for the Evaluation of Chronic Allograft Vasculopathy in Transplant Recipients

    AMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2009
    G. Korosoglou
    The aim of our study was to investigate the ability of Strain-Encoded magnetic resonance imaging (MRI) to detect cardiac allograft vasculopathy (CAV) in heart transplantation (HTx)-recipients. In consecutive subjects (n = 69), who underwent cardiac catheterization, MRI was performed for quantification of myocardial strain and perfusion reserve. Based on angiographic findings subjects were classified: group A including patients with normal vessels; group B, patients with stenosis <50%; and group C, patients with severe CAV (stenosis , 50%). Significant correlations were observed between myocardial perfusion reserve with peak systolic strain (r =,0.53, p < 0.001) and with mean diastolic strain rate (r = 0.82, p < 0.001). Peak systolic strain and strain rate were significantly reduced only in group C, while mean diastolic strain rate and myocardial perfusion reserve were already reduced in group B and A. Myocardial perfusion reserve and mean diastolic strain rate had higher accuracy for the detection of CAV (AUC = 0.95, 95% CI = 0.87,0.99 and AUC = 0.93, 95% CI = 0.84,0.98, respectively) and followed peak systolic strain and strain rate (AUC = 0.80, 95% CI = 0.69,0.89 and AUC = 0.78, 95% CI = 0.67,0.87, respectively). Besides the quantification of myocardial perfusion, the estimation of the diastolic strain rate is a useful parameter for CAV assessment. In combination with the clinical evaluation, these parameters may be effective tools for the routine surveillance of HTx-recipients. [source]

    Effects of Primary Percutaneous Coronary Intervention on P Wave Dispersion

    ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2005
    Turgay Celik M.D.
    Background: Several studies demonstrated that P wave dispersion (PWD) increased after coronary occlusion. The effect of primary percutaneous coronary intervention (PCI) on PWD needs to be elucidated. Methods: The study consisted of 125 patients with acute myocardial infarction (110 men, mean age 59.8 ± 7.8 years) undergoing primary PCI. The patients were divided into three groups according to thrombolysis in myocardial infarction myocardial perfusion grade (TMPG) after successful PCI. Groups 1 (n = 12), 2 (n = 9), and 3 (n = 104) included the patients with TMPG 0/1, 2, 3, respectively. Electrocardiograms were obtained before and approximately 66 ± 18 minutes after PCI. Results: PWD and Pmaximum after PCI were significantly lower than the preintervention values (P < 0.001 for both). When PWD and Pmaximum values after PCI were compared among groups, PWD and Pmaximum in groups 1 and 2 were found to be higher than those of group 3 (P < 0.001 for PWD and Pmaximum). Atrial fibrillation (AF) occurred in 14 patients. Pmaximum and PWD in patients with AF were higher compared to those of the patients without AF (P < 0.001 for both P wave parameters). Also more frequent AF attacks were observed in group 1 compared to group 3 (P < 0.001). Conclusions: PWD and Pmaximum after primary PCI were lower compared to the preintervention values. Prolonged PWD in patients with poor myocardial perfusion can contribute to increased mortality, and also it can can be combined with ST segment resolution to predict clinical reperfusion and might help in predicting AF. [source]

    The Effect of Myocardial Surgical Revascularization on Left Ventricular Late Potentials

    ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2001
    Levent Can M.D.
    Background: The presence of ventricular late potentials (LP) is an important indicator for the development of ventricular tachyarrhythmias due to ischemic heart disease. The effect of myocardial revascularization on LP has remained controversial. The purpose of this study was to determine whether complete myocardial surgical revascularization (CABG) documented by myocardial perfusion scintigraphy might alter the substrate responsible for LP. Methods: Prospectively, enrolled patients undergoing elective CABG were evaluated with thallium-201 myocardial perfusion scintigraphy and signal- averaged ECG pre- and postoperatively. SAECG recordings were obtained serially: before, 48,72 hours and 3 months after CABG. LPS were defined as positive if SAECG met at least two of Gomes criteria. Scintigraphies were performed pre-and 3 months postoperatively for determination of the success of revascularization. Changes observed in SAECG recordings after CABG were compared between those with and without successful revascularization. Results: CABG resulted in successful revascularization in 23 patients and was unsuccessful in 17 (no change or deterioration of the perfusion defects). Preoperative SAECG values were not different between groups except for RMS values. The incidence of LP decreased significantly postoperatively in patients with improved myocardial perfusion, whereas there were no changes in patients who did not have postoperative perfusion improvement (McNemar test, P < 0.05). Conclusions: LPs disappear following the elimination of myocardial ischemia by complete surgical revascularization. Persistence of ischemia following CABG usually results in the persistence of late potentials. The incidence of ventricular arrhythmias is expected to be unchanged in these patients and they should be reevaluated for reinterventions. A.N.E. 2001;6(2):84,91 [source]

    Feasibility and applicability of computer-assisted myocardial blush quantification after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction,

    CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 5 2010
    Joost D.E. Haeck MD
    Abstract Objectives: The aim of the study was to evaluate whether the "Quantitative Blush Evaluator" (QuBE) score is associated with measures of myocardial reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) treated in two hospitals with 24/7 coronary intervention facilities. Background: QuBE is an open source computer program to quantify myocardial perfusion. Although QuBE has shown to be practical and feasible in the patients enrolled in the Thrombus Aspiration during Percutaneous Coronary Intervention in Acute Myocardial Infarction Study (TAPAS), QuBE has not yet been verified on reperfusion outcomes of primary percutaneous coronary intervention (PCI) patients treated in other catheterization laboratories. Methods: Core lab adjudicated angiographic outcomes and QuBE values were assessed on angiograms of patients who were enrolled in the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-Elevation (PREPARE) trial. ST-segment resolution immediately after PCI measured by continuous ST Holter monitoring was calculated by a blinded core lab. Results: The QuBE score could be assessed on 229 of the 284 angiograms (81%) and was significantly associated with visually assessed myocardial blush grade (P < 0.0001). Patients with improved postprocedural Thrombolysis in Myocardial Infarction-graded flow, myocardial blush grade, ST-segment resolution immediately after PCI, or a small infarct size measured by peak CK-MB had a significant better QuBE score. Conclusions: QuBE is feasible and applicable at angiograms of patients with STEMI recorded at other catheterization laboratories and is associated with measures of myocardial reperfusion. © 2010 Wiley-Liss, Inc. [source]

    Catheter-based ventricle-coronary vein bypass

    CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2005
    Motoya Hayase MD
    Abstract The goal of this study was to investigate the feasibility of a catheter-based ventricle-to-coronary vein bypass (VPASS) in order to achieve retrograde myocardial perfusion by a conduit (VSTENT) from the left ventricle (LV) to the anterior interventricular vein (AIV). Percutaneous coronary venous arterialization has been proposed as a potential treatment strategy for otherwise untreatable coronary artery disease. In an acute setting, the VSTENT implant was deployed percutaneously using the VPASS procedure in five swine. Coronary venous flow and pressure patterns were measured before and after VSTENT implant deployment with and without AIV and left anterior descending artery (LAD) occlusion. In a separate chronic pilot study, the VPASS procedure was completed on two animals that had a mid-LAD occlusion or LAD stenosis. At day 30 post-VPASS procedure, left ventriculography and magnetic resonance imaging (MRI) were performed to assess the patency and myocardial viability of the VSTENT implants. Pre-VSTENT implantation, the mid-AIV systolic wedge pressure was significantly lower than LV systolic pressure during AIV blockage (46 ± 19 vs. 90 ± 16 mm Hg; P < 0.01). The VSTENT implant deployment was performed without complication and achieved equalization of the AIV and LV systolic pressures and creation of retrograde flow in the distal AIV (maximal flow velocity: 37 ± 7 cm/sec). At day 30 post-VPASS procedure, left ventriculography showed VSTENT implant patency. MRI perfusion images demonstrated myocardial viability even with an LAD occlusion. Coronary retrograde perfusion using the VPASS procedure is feasible and may represent a potential technique for end-stage myocardial ischemia. Catheter Cardiovasc Interv 2005. © 2005 Wiley-Liss, Inc. [source]

    Abnormal myocardial perfusion and contractile recruitment during exercise in type 1 diabetic patients

    CLINICAL CARDIOLOGY, Issue 2 2005
    Roldano Scognamiglio M.D.
    Abstract Background: No data are available on the relationship between myocardial perfusion and left ventricular (LV) function in type 1 diabetes mellitus (T1DM), which may constitute a factor explaining the progressive contractile dysfunction to the overt phase of diabetic cardiomyopathy. Hypothesis: This study was undertaken to test whether myocardial perfusion abnormalities are present at rest and during exercise and whether they are related to contractile dysfunction in T1DM. Methods: Twenty-two patients with T1DM, aged 32 ± 8.3 years, without macro-or microvascular complications, and 10 controls, aged 31 ± 3 years, were studied. Left ventricular function and myocardial perfusion were assessed by two-dimensional and myocardial contrast echocardiography at rest and during handgrip (HG). Results: Fourteen patients with T1DM showed a decline in LV ejectionfraction (LVEF) during HG (Group 1) while 8 had a normal response (Group 2). Both basal myocardial blood volume (MBV) and velocity ((3) were normal inT1DM. During exercise, MBV and (3 increased and were associated with an increase in myocardial blood flow (MBF) in controls. In T1DM, (3 did not change and MBV increased only in Group 2, while this increase was not observed in Group 1 (controls: 14.9 ±2.3 vs. Group 1:7.6± 1.6, p< 0.001; and vs. Group2:10.2± 2.8, p<0.001), (3(0.86±0.12vs.0.68±0.14, p<0.001;and vs. 0.67±0.15, p<0.001). A correlation between the ratio exercise MBF/resting MBF and LVEF at peak exercise in T1DM was observed (r=0.805, p< 0.001). Conclusions: A large proportion of patients with T1DM exhibit abnormalities in myocardial adaptable capacity to match an acute overload, which are related to a defective increase in myocardial perfusion. [source]

    Low radiation dose imaging of myocardial perfusion and coronary angiography with a hybrid PET/CT scanner

    CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2009
    S. Kajander
    Summary Objectives:, To test the image quality and feasibility of a sequential low radiation dose protocol for hybrid cardiac PET/CT angiography (CTA). Background:, Multidetector computed tomography (MDCT) is a non-invasive method for coronary angiography. The negative predictive value of MDCT is high but perfusion imaging has a role in detecting functional significance of coronary lesions. This has encouraged combining these techniques. However, radiation dose is of concern. We report our first experiences with a low dose sequential CTA mode applicable to hybrid imaging. Methods:, In the first phase, 10 consecutive cardiac MDCT angiographies were performed with spiral acquisition and compared in terms of image quality and dose with the following 10 patients performed with a new sequential mode. In the second phase, feasibility and radiation dose of a combined 15O-water rest-stress PET perfusion/sequential CTA protocol were assessed in another group of 61 consecutive patients. Results:, Mean effective radiation dose was 60% lower in the sequential group than in the spiral group (19·3 versus 7·6 mSv, P<0·001). In the second phase, the new sequential hybrid protocol proved possible in 87% of the patients given the preconditions determined by the manufacturer. Mean effective dose of the CT acquisition was 7·6 mSv and total dose from the PET/CTA hybrid study 9·5 mSv. Conclusion:, Low dose PET/CT allows cardiac hybrid studies with <10 mSv. The protocol can be applied to almost nine out of 10 patients with CT image quality comparable to spiral acquisition. [source]

    To what degree is amelioration of angina following coronary revascularization associated with improvement in myocardial perfusion?

    CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2006
    Allan Johansen
    Summary Objective:, To examine the association between changes in chest pain and changes in perfusion following revascularization as assessed by clinical evaluation and myocardial perfusion imaging (MPI) in patients with stable angina. Design:, In a prospective series of 380 patients (58·8 ± 8·8 years) referred to angiography because of known or suspected stable angina, changes in chest discomfort and changes in perfusion after 2 years were assessed in 144 patients, who underwent revascularization, and 236, who did not. The decision to treat invasively was made without knowledge of the result of MPI. Results:, In revascularized patients, the presence of typical/atypical angina was reduced from 93% to 36% and the improvement was associated with improvement in perfusion. A small improvement in perfusion induced a high frequency of change from angina to no pain, whereas a further reduction caused little extra change. In non-revascularized patients the change in chest discomfort was not related to changes in perfusion, which were rarely present. Conclusion:, Alleviation of chest discomfort 2 years after revascularization is associated with improvements in perfusion. This association appeared to be an all-or-nothing phenomenon. Non-revascularized patients also exhibited improvements in chest discomfort despite insignificant changes in perfusion. [source]

    Evaluation of left ventricular volumes and ejection fraction by automated gated myocardial SPECT versus cardiovascular magnetic resonance

    CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 3 2005
    Eva Persson
    Summary Background:, Electrocardiogram-gated myocardial single-photon emission computed tomography (SPECT) with 99mTc-tetrofosmin allows simultaneous evaluation of myocardial perfusion and function. In this study, left ventricular volumes, ejection fraction (LVEF), and left ventricular wall volume (LVWV) derived from gated SPECT were compared with measurements from cardiovascular magnetic resonance (CMR), performed within a few hours. Methods:, The study population included 55 patients with known or suspected coronary artery disease, including 13 patients with recent acute myocardial infarction. End-diastolic (EDV) and end-systolic (ESV) volumes, LVEF and LVWV were derived automatically from gated SPECT using commercially available software (QGS). In the CMR studies, manually delineated endocardial and epicardial borders on short-axis slices were used to calculate the volumes. Results:, Gated SPECT underestimated EDV by 35 ± 14 ml (mean ± SD) (P<0·001), ESV by 10 ± 13 ml (P<0·001), and LVEF by 4 ± 7 percentage points (P<0·001). There were no systematic difference in EDV, ESV or LVEF between the methods. SPECT underestimated LVWV by 49 ± 30 ml (P<0·001), with a trend towards increasing underestimation by SPECT for larger wall volumes. Conclusion:, These findings show that gated SPECT slightly underestimates EDV, ESV and LVEF compared with CMR. This underestimation is systematic, however, indicating that ventricular volumes derived from gated SPECT are robust enough to guide clinical management. Estimates of LVWV in patients with large wall volumes are less accurate. [source]