George Beller - Academia.edu (original) (raw)
Papers by George Beller
Developments in Cardiovascular Medicine, 1992
Pharmacologic stress Tl-201 imaging utilizing either intravenous dipyridamole or adenosine is an ... more Pharmacologic stress Tl-201 imaging utilizing either intravenous dipyridamole or adenosine is an acceptable alternative to exercise imaging for detection of coronary artery disease (CAD) and determining prognosis. Data from multiple published series indicate an 85 % sensitivity and 90 % specificity for CAD detection for dipyridamole imaging. Ischemia can be distinguished from scar with the same accuracy as achieved with
Global Heart, 2015
The vision of the World Heart Federation is to drive efforts to reduce premature cardiovascular d... more The vision of the World Heart Federation is to drive efforts to reduce premature cardiovascular disease-related death globally by at least 25% by 2025. To help achieve this goal, the World Heart Federation has initiated the Emerging Leaders program, which aims to use expertise among leaders in implementation science, health systems, and health policy research and to work with at least 100 emerging leaders over the next decade to initiate and facilitate cardiovascular disease prevention activities globally and in every region of the world. In this report, we describe the rationale for and characteristics of the Emerging Leaders program, including its training objectives, methods, and future directions. The Emerging Leaders program represents a major opportunity for the World Heart Federation, its member organizations, and the emerging leaders themselves to leverage their collective strengths toward achieving the ambitious, yet achievable, "25 Â 25" goal through an innovative global collaborative leadership-enhancing experience.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2003
Bis(N-ethoxy,N-ethyldithiocarbamato)nitrido technetium (V) ((99m)Tc) ((99m)TcN-NOET) is a myocard... more Bis(N-ethoxy,N-ethyldithiocarbamato)nitrido technetium (V) ((99m)Tc) ((99m)TcN-NOET) is a myocardial perfusion imaging agent demonstrating significant redistribution and currently in phase III clinical trials. Previous studies have suggested that (99m)TcN-NOET is bound intravascularly. Therefore, we sought to determine whether modifications in the vascular compartment would provide further insights into the mechanisms of (99m)TcN-NOET myocardial washout and redistribution. (99m)TcN-NOET cardiac washout was studied ex vivo in 15 isolated perfused rat hearts after bolus injection (1.5 MBq) in the absence (n = 6) or presence of bovine serum albumin ([BSA] 0.03%) with (n = 5) or without (n = 4) bound lipids. The intrinsic myocardial washout of the tracer was also studied in vivo in 6 dogs after intracoronary bolus injection of the tracer (0.75 MBq) before and after hyperlipidemia induced by intravenous administration of 300 mL of 20% intralipids (n = 3) or hyperemia induced by intraveno...
Background-99m Tc-RP517 is a new leukotriene B 4 (LTB4) receptor antagonist developed for imaging... more Background-99m Tc-RP517 is a new leukotriene B 4 (LTB4) receptor antagonist developed for imaging acute inflammation or infection. A unique property of 99m Tc-RP517 is its ability to label white blood cells in vivo after intravenous injection. The goals of this study were to determine relative 99m Tc-RP517 binding to human leukocyte subtypes and the 99m Tc-RP517 uptake pattern in canine myocardium where inflammation was induced by either coronary occlusion and reperfusion or tumor necrosis factor ␣ (TNF␣) injection.
Journal of the American College of Cardiology, 2003
Background: Left ventricular systolic and diastolic functions have been recognized as important f... more Background: Left ventricular systolic and diastolic functions have been recognized as important factors in cardiovascular diseases. Conductance catheter has high temporal resolution and can provide accurate measurements of cardiac functions. However, it has been difficult to obtain an accurate assessment of left ventricular function by using noninvasive techn;ques. Steady state tine MR imaging is a new MR Imaging technique that can demonstrate improved temporal resolution in the cardiac cycle. In addition, high blood-to-myocardial contrast can be obtained in patients with heart failure. The purpose of this study was to evaluate the accuracy of steady state tine MR imaging for assessing left ventricular volumes and functions by using a conductance catheter method as a gold standard. Methods: Fourteen patients (9 man, mean age 60.4*11.3 years) with heart tailure (7 with dilated cardiomyopathy, 5 with old myocardial infarction, 2 with constrictive pericarditis) were studied. Left ventricular time-volume curves were obtained with steady state tree precession tine MR imaaina and with a smole-field conductance catheter usina a micromanometer. End-diastolic volume (EDV). end-systolic volume (ESV) and ejection fraction (EFI were calculated. In addition. oeak eiection rate (PER\. time to PER. oeak ., _ I. tilling rate (PFR) end time to PFR were assessed by the first derivative curve of the left ventricular time volume curve. Temporal resolutions was 26 msec by MR imaging and 3 msec by conductance catheter. Results: Excellent tine MR images were acquired in all patients by using steady state tine MR imaging. Significant linear correlation between the measurements by MR lmaglng and conductance catheter was found for EDV (r=0.98. pcO.OOi), ESV (r=0.99, pcO.OOl), EF (r&97, pcO.OOl), PER (r=0.76, pcO.Ol), time to PER (r=0.78. p<O.Ol), PFR (r=O.E6, ~~0.05) and time to PFR (rz0.77, p<O.Ol). Conclusion: MR measurements of LV volume, EF, PER and PFR obtained by using a steady state tine MR imagmg demonstrated good correlations with those assessed by conductance catheter. Cardiac MR imaging is a noninvasive method that can provide detailed analysis of the cardiac performance in patients with LV dysfunction.
Journal of the American College of Cardiology, 2003
Background: Left ventricular systolic and diastolic functions have been recognized as important f... more Background: Left ventricular systolic and diastolic functions have been recognized as important factors in cardiovascular diseases. Conductance catheter has high temporal resolution and can provide accurate measurements of cardiac functions. However, it has been difficult to obtain an accurate assessment of left ventricular function by using noninvasive techn;ques. Steady state tine MR imaging is a new MR Imaging technique that can demonstrate improved temporal resolution in the cardiac cycle. In addition, high blood-to-myocardial contrast can be obtained in patients with heart failure. The purpose of this study was to evaluate the accuracy of steady state tine MR imaging for assessing left ventricular volumes and functions by using a conductance catheter method as a gold standard. Methods: Fourteen patients (9 man, mean age 60.4*11.3 years) with heart tailure (7 with dilated cardiomyopathy, 5 with old myocardial infarction, 2 with constrictive pericarditis) were studied. Left ventricular time-volume curves were obtained with steady state tree precession tine MR imaaina and with a smole-field conductance catheter usina a micromanometer. End-diastolic volume (EDV). end-systolic volume (ESV) and ejection fraction (EFI were calculated. In addition. oeak eiection rate (PER\. time to PER. oeak ., _ I. tilling rate (PFR) end time to PFR were assessed by the first derivative curve of the left ventricular time volume curve. Temporal resolutions was 26 msec by MR imaging and 3 msec by conductance catheter. Results: Excellent tine MR images were acquired in all patients by using steady state tine MR imaging. Significant linear correlation between the measurements by MR lmaglng and conductance catheter was found for EDV (r=0.98. pcO.OOi), ESV (r=0.99, pcO.OOl), EF (r&97, pcO.OOl), PER (r=0.76, pcO.Ol), time to PER (r=0.78. p<O.Ol), PFR (r=O.E6, ~~0.05) and time to PFR (rz0.77, p<O.Ol). Conclusion: MR measurements of LV volume, EF, PER and PFR obtained by using a steady state tine MR imagmg demonstrated good correlations with those assessed by conductance catheter. Cardiac MR imaging is a noninvasive method that can provide detailed analysis of the cardiac performance in patients with LV dysfunction.
Journal of the American College of Cardiology, 2003
We hypothesized that combining functional assessment to perfusion enhances the ability of electro... more We hypothesized that combining functional assessment to perfusion enhances the ability of electrocardiographic gating Tc-99m sestamibi single photon emission computed tomography (gated SPECT) myocardial perfusion imaging (MPI) to detect defects in multiple vascular territories in patients with severe three-vessel coronary artery disease (3VD). BACKGROUND In patients with 3VD, perfusion defects in multiple vascular territories may not always be evident due to globally reduced perfusion.
Journal of the American College of Cardiology, 1989
The myocardial uptake of a new technetium-99m-labeled myocardial perfusion agent, methoxyisobutyl... more The myocardial uptake of a new technetium-99m-labeled myocardial perfusion agent, methoxyisobutyl isonitrile (Tc-99m MIBI), and thallium-201 was correlated with microsphere flow in an open chest canine model of low coronary flow and postischemic dysfunction. Eighteen dogs were given an injection of thallium-201 (0.5 mCi) and Tc-99m MIBI (5 mCi) either after 40 min of partial left anterior descending artery occlusion (Group I, 10 dogs) or during reperfusion after 15 min of left anterior descending artery occlusion (Group II, 8 dogs). Regional dysfunction was documented during injection in both groups by quantitative two-dimensional echocardiography. Regional blood flow was assessed by radiolabeled microspheres. The heart was excised 15 min after radionuclide injection and the left ventricle divided into 96 segments for gamma well counting.
Journal of the American College of Cardiology, 1983
Becausethallium-20l uptake relates directly to the amount of viable myocardium and nutrient blood... more Becausethallium-20l uptake relates directly to the amount of viable myocardium and nutrient blood flow, the potential for exercise scintigraphy to predict response to coronary revascularization surgery was investigated in 47 consecutive patients. All patients underwent thallium-201 scintigraphy and coronary angiography at a mean (± standard deviation) of 4.3 ± 3.1 weeks before and 7.5 ± 1.6 weeks after surgery. Thallium uptake and washout were computer-quantified and each of six segments was defined as normal, showing total or partial redistribution or a persistent defect. Persistent defects were further classified according to the percent reduction in regional thallium activity; PD 25 -50 denoted a 25 to 50% constant reduction in relative thallium activity and PD> 50 denoted a greater than 50% reduction. Of 82 segments with total redistribution before surgery, 76 (93%) showed normal thallium uptake and washout postoperatively, versus only 16 (73%) of 22 with partial redistribution (probability [p] = 0.01). Preoperative ventriculography revealed that 95% ofthe segments with total redistribution had preserved wall motion, versus only 74% of those with partial redistribution (p =0.01).
Journal of the American College of Cardiology, 1997
The purpose of this study was to determine how frequently and for what reasons the addition of el... more The purpose of this study was to determine how frequently and for what reasons the addition of electrocardiographically gated technetium-99m (Tc-99m) sestamibi single-photon emission computed tomographic (SPECT) images add value to nongated SPECT perfusion images. Electrocardiographic gating of Tc-99m sestamibi SPECT images permits assessment of regional and global left ventricular function and may assist in differentiating attenuation artifacts from myocardial scar. A total of 285 consecutive patients (143 women and 142 men; mean age 57.6 +/- 11.5 years) underwent gated SPECT Tc-99m sestamibi imaging (212 with exercise, 63 with dipyridamole and 10 with dobutamine). The conventional stress and rest tomograms were interpreted first by means of a 14-segment scoring system, and then the studies were reinterpreted while the gated images were viewed. In the total group of 285 patients, the number of "borderline" interpretations was reduced from 89 to 29. In the 137 patients with a < or = 10% pretest likelihood of coronary artery disease, the addition of gated images added significantly to the percentage of interpretations that were designated "normal" (74% [101 of 137] vs. 93% [127 of 137], p < 0.0001), due to a reduction in borderline normal and borderline abnormal readings. In 49 patients with a previous infarction or recent angiography with > or = 70% stenosis, or both, the addition of gated images changed the percentage of "abnormal" scan interpretations from 78% (38 of 49) to 92% (45 of 49). This result was not significant (p = 0.09, two-tailed), but the trend was toward a greater number of unequivocal abnormal interpretations in this subgroup. The addition of electrocardiographically gated Tc-99m sestamibi SPECT images to the reading of stress and rest perfusion images alone resulted in shifting the final scan interpretations to a more normal designation in patients with a low pretest likelihood of coronary artery disease, and to more abnormal defects consistent with coronary artery disease in patients with known coronary artery disease. The number of "borderline normal" and "borderline abnormal" interpretations are significantly reduced when gated SPECT images are interpreted simultaneously with stress and rest perfusion images.
Journal of the American College of Cardiology, 2003
Journal of the American College of Cardiology, 2002
The study was done to determine the effects of propranolol, enalaprilat, verapamil, and caffeine ... more The study was done to determine the effects of propranolol, enalaprilat, verapamil, and caffeine on the vasodilatory properties of the adenosine A(2A)-receptor agonist ATL-146e (ATL). ATL is a new adenosine A(2A)-receptor agonist proposed as a vasodilator for myocardial stress perfusion imaging. Beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium blockers are commonly used for the treatment of coronary artery disease (CAD), and their effect on ATL-mediated vasodilation is unknown. Dietary intake of caffeine is also common. In 19 anesthetized, open-chest dogs, hemodynamic responses to bolus injections of ATL (1.0 microg/kg) and adenosine (60 microg/kg) were recorded before and after administration of propranolol (1.0 mg/kg, ATL only), enalaprilat (0.3 mg/kg, ATL only), caffeine (5.0 mg/kg, ATL only), and verapamil (0.2 mg/kg bolus, ATL and adenosine). Neither propranolol nor enalaprilat attenuated the ATL-mediated vasodilation (225 +/- 86% and 237 +/- 67% increase, respectively, p = NS vs. control). Caffeine had an inhibitory effect (97 +/- 28% increase, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05 vs. control). Verapamil blunted both ATL- and adenosine-induced vasodilation (63 +/- 20% and 35 +/- 7%, respectively, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05 vs. baseline), and also inhibited the vasodilation induced by the adenosine triphosphate-sensitive potassium (K(ATP)) channel activator pinacidil. Beta-blockers and ACE inhibitors do not reduce the maximal coronary flow response to adenosine A(2A)-agonists, whereas verapamil attenuated this vasodilation through inhibition of K(ATP) channels. The inhibitory effect of verapamil and K(ATP) channel inhibitors like glybenclamide on pharmacologic stress using adenosine or adenosine A(2A)-receptor agonists should be evaluated in the clinical setting to determine their potential for reducing the sensitivity of CAD detection with perfusion imaging.
Journal of the American College of Cardiology, 2011
Journal of the American College of Cardiology, 2003
We hypothesized that fractional flow reserve (FFR) of an infarct-related artery (IRA) early after... more We hypothesized that fractional flow reserve (FFR) of an infarct-related artery (IRA) early after myocardial infarction (MI) identifies inducible ischemia on noninvasive imaging. BACKGROUND Early after MI, IRAs frequently have angiographically indeterminant lesions. Whether FFR can detect reversible perfusion defects early after MI when dynamic microvascular abnormalities are present is not known.
Journal of the American College of Cardiology, 2000
Journal of the American College of Cardiology, 2002
Journal of Nuclear Cardiology, 2012
This study examined short-term cardiac catheterization rates and medication changes after cardiac... more This study examined short-term cardiac catheterization rates and medication changes after cardiac imaging.
Journal of Nuclear Cardiology, 2004
Journal of Nuclear Cardiology, 2006
Technetium 99m N-DBODC5 is a new myocardial perfusion tracer shown to exhibit high heart uptake a... more Technetium 99m N-DBODC5 is a new myocardial perfusion tracer shown to exhibit high heart uptake and rapid liver clearance in normal rats. The objectives of this canine study were (1) to compare the organ biodistribution and myocardial uptake, washout, and redistribution kinetics of Tc-99m N-DBODC5 with Tc-99m sestamibi over a period of 3 hours in a more clinically relevant large animal species and (2) to compare the myocardial uptake of Tc-99m N-DBODC5 with thallium 201 when co-injected during vasodilator stress in dogs with coronary stenoses. At peak adenosine-induced hyperemia, 10 dogs with critical left anterior descending artery stenoses received either Tc-99m N-DBODC5 (n = 6) or Tc-99m sestamibi (n = 4) and microspheres, followed by serial imaging and blood sampling over a period of 3 hours. Another 14 dogs with either critical (n = 7) or mild (n = 7) left anterior descending artery stenoses underwent simultaneous injection of Tc-99m N-DBODC5, Tl-201, and microspheres during peak vasodilator stress. Like sestamibi, Tc-99m N-DBODC5 showed good myocardial uptake with slow washout and minimal redistribution over a period of 3 hours (P = not significant); however, Tc-99m N-DBODC5 cleared more rapidly from the liver (heart-lung ratio at 30 minutes, 0.92+/-0.11 versus 0.51 +/- 0.05; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). When injected during hyperemic flow, the myocardial extraction plateau for Tc-99m N-DBODC5 was lower than that for Tl-201 and was intermediate between Tc-99m sestamibi and Tc-99m tetrofosmin. Excellent organ biodistribution and myocardial uptake and clearance kinetic properties, combined with rapid liver clearance and a favorable flow-extraction relationship, make Tc-99m N-DBODC5 a very promising new myocardial perfusion imaging agent.
Developments in Cardiovascular Medicine, 1992
Pharmacologic stress Tl-201 imaging utilizing either intravenous dipyridamole or adenosine is an ... more Pharmacologic stress Tl-201 imaging utilizing either intravenous dipyridamole or adenosine is an acceptable alternative to exercise imaging for detection of coronary artery disease (CAD) and determining prognosis. Data from multiple published series indicate an 85 % sensitivity and 90 % specificity for CAD detection for dipyridamole imaging. Ischemia can be distinguished from scar with the same accuracy as achieved with
Global Heart, 2015
The vision of the World Heart Federation is to drive efforts to reduce premature cardiovascular d... more The vision of the World Heart Federation is to drive efforts to reduce premature cardiovascular disease-related death globally by at least 25% by 2025. To help achieve this goal, the World Heart Federation has initiated the Emerging Leaders program, which aims to use expertise among leaders in implementation science, health systems, and health policy research and to work with at least 100 emerging leaders over the next decade to initiate and facilitate cardiovascular disease prevention activities globally and in every region of the world. In this report, we describe the rationale for and characteristics of the Emerging Leaders program, including its training objectives, methods, and future directions. The Emerging Leaders program represents a major opportunity for the World Heart Federation, its member organizations, and the emerging leaders themselves to leverage their collective strengths toward achieving the ambitious, yet achievable, "25 Â 25" goal through an innovative global collaborative leadership-enhancing experience.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2003
Bis(N-ethoxy,N-ethyldithiocarbamato)nitrido technetium (V) ((99m)Tc) ((99m)TcN-NOET) is a myocard... more Bis(N-ethoxy,N-ethyldithiocarbamato)nitrido technetium (V) ((99m)Tc) ((99m)TcN-NOET) is a myocardial perfusion imaging agent demonstrating significant redistribution and currently in phase III clinical trials. Previous studies have suggested that (99m)TcN-NOET is bound intravascularly. Therefore, we sought to determine whether modifications in the vascular compartment would provide further insights into the mechanisms of (99m)TcN-NOET myocardial washout and redistribution. (99m)TcN-NOET cardiac washout was studied ex vivo in 15 isolated perfused rat hearts after bolus injection (1.5 MBq) in the absence (n = 6) or presence of bovine serum albumin ([BSA] 0.03%) with (n = 5) or without (n = 4) bound lipids. The intrinsic myocardial washout of the tracer was also studied in vivo in 6 dogs after intracoronary bolus injection of the tracer (0.75 MBq) before and after hyperlipidemia induced by intravenous administration of 300 mL of 20% intralipids (n = 3) or hyperemia induced by intraveno...
Background-99m Tc-RP517 is a new leukotriene B 4 (LTB4) receptor antagonist developed for imaging... more Background-99m Tc-RP517 is a new leukotriene B 4 (LTB4) receptor antagonist developed for imaging acute inflammation or infection. A unique property of 99m Tc-RP517 is its ability to label white blood cells in vivo after intravenous injection. The goals of this study were to determine relative 99m Tc-RP517 binding to human leukocyte subtypes and the 99m Tc-RP517 uptake pattern in canine myocardium where inflammation was induced by either coronary occlusion and reperfusion or tumor necrosis factor ␣ (TNF␣) injection.
Journal of the American College of Cardiology, 2003
Background: Left ventricular systolic and diastolic functions have been recognized as important f... more Background: Left ventricular systolic and diastolic functions have been recognized as important factors in cardiovascular diseases. Conductance catheter has high temporal resolution and can provide accurate measurements of cardiac functions. However, it has been difficult to obtain an accurate assessment of left ventricular function by using noninvasive techn;ques. Steady state tine MR imaging is a new MR Imaging technique that can demonstrate improved temporal resolution in the cardiac cycle. In addition, high blood-to-myocardial contrast can be obtained in patients with heart failure. The purpose of this study was to evaluate the accuracy of steady state tine MR imaging for assessing left ventricular volumes and functions by using a conductance catheter method as a gold standard. Methods: Fourteen patients (9 man, mean age 60.4*11.3 years) with heart tailure (7 with dilated cardiomyopathy, 5 with old myocardial infarction, 2 with constrictive pericarditis) were studied. Left ventricular time-volume curves were obtained with steady state tree precession tine MR imaaina and with a smole-field conductance catheter usina a micromanometer. End-diastolic volume (EDV). end-systolic volume (ESV) and ejection fraction (EFI were calculated. In addition. oeak eiection rate (PER\. time to PER. oeak ., _ I. tilling rate (PFR) end time to PFR were assessed by the first derivative curve of the left ventricular time volume curve. Temporal resolutions was 26 msec by MR imaging and 3 msec by conductance catheter. Results: Excellent tine MR images were acquired in all patients by using steady state tine MR imaging. Significant linear correlation between the measurements by MR lmaglng and conductance catheter was found for EDV (r=0.98. pcO.OOi), ESV (r=0.99, pcO.OOl), EF (r&97, pcO.OOl), PER (r=0.76, pcO.Ol), time to PER (r=0.78. p<O.Ol), PFR (r=O.E6, ~~0.05) and time to PFR (rz0.77, p<O.Ol). Conclusion: MR measurements of LV volume, EF, PER and PFR obtained by using a steady state tine MR imagmg demonstrated good correlations with those assessed by conductance catheter. Cardiac MR imaging is a noninvasive method that can provide detailed analysis of the cardiac performance in patients with LV dysfunction.
Journal of the American College of Cardiology, 2003
Background: Left ventricular systolic and diastolic functions have been recognized as important f... more Background: Left ventricular systolic and diastolic functions have been recognized as important factors in cardiovascular diseases. Conductance catheter has high temporal resolution and can provide accurate measurements of cardiac functions. However, it has been difficult to obtain an accurate assessment of left ventricular function by using noninvasive techn;ques. Steady state tine MR imaging is a new MR Imaging technique that can demonstrate improved temporal resolution in the cardiac cycle. In addition, high blood-to-myocardial contrast can be obtained in patients with heart failure. The purpose of this study was to evaluate the accuracy of steady state tine MR imaging for assessing left ventricular volumes and functions by using a conductance catheter method as a gold standard. Methods: Fourteen patients (9 man, mean age 60.4*11.3 years) with heart tailure (7 with dilated cardiomyopathy, 5 with old myocardial infarction, 2 with constrictive pericarditis) were studied. Left ventricular time-volume curves were obtained with steady state tree precession tine MR imaaina and with a smole-field conductance catheter usina a micromanometer. End-diastolic volume (EDV). end-systolic volume (ESV) and ejection fraction (EFI were calculated. In addition. oeak eiection rate (PER\. time to PER. oeak ., _ I. tilling rate (PFR) end time to PFR were assessed by the first derivative curve of the left ventricular time volume curve. Temporal resolutions was 26 msec by MR imaging and 3 msec by conductance catheter. Results: Excellent tine MR images were acquired in all patients by using steady state tine MR imaging. Significant linear correlation between the measurements by MR lmaglng and conductance catheter was found for EDV (r=0.98. pcO.OOi), ESV (r=0.99, pcO.OOl), EF (r&97, pcO.OOl), PER (r=0.76, pcO.Ol), time to PER (r=0.78. p<O.Ol), PFR (r=O.E6, ~~0.05) and time to PFR (rz0.77, p<O.Ol). Conclusion: MR measurements of LV volume, EF, PER and PFR obtained by using a steady state tine MR imagmg demonstrated good correlations with those assessed by conductance catheter. Cardiac MR imaging is a noninvasive method that can provide detailed analysis of the cardiac performance in patients with LV dysfunction.
Journal of the American College of Cardiology, 2003
We hypothesized that combining functional assessment to perfusion enhances the ability of electro... more We hypothesized that combining functional assessment to perfusion enhances the ability of electrocardiographic gating Tc-99m sestamibi single photon emission computed tomography (gated SPECT) myocardial perfusion imaging (MPI) to detect defects in multiple vascular territories in patients with severe three-vessel coronary artery disease (3VD). BACKGROUND In patients with 3VD, perfusion defects in multiple vascular territories may not always be evident due to globally reduced perfusion.
Journal of the American College of Cardiology, 1989
The myocardial uptake of a new technetium-99m-labeled myocardial perfusion agent, methoxyisobutyl... more The myocardial uptake of a new technetium-99m-labeled myocardial perfusion agent, methoxyisobutyl isonitrile (Tc-99m MIBI), and thallium-201 was correlated with microsphere flow in an open chest canine model of low coronary flow and postischemic dysfunction. Eighteen dogs were given an injection of thallium-201 (0.5 mCi) and Tc-99m MIBI (5 mCi) either after 40 min of partial left anterior descending artery occlusion (Group I, 10 dogs) or during reperfusion after 15 min of left anterior descending artery occlusion (Group II, 8 dogs). Regional dysfunction was documented during injection in both groups by quantitative two-dimensional echocardiography. Regional blood flow was assessed by radiolabeled microspheres. The heart was excised 15 min after radionuclide injection and the left ventricle divided into 96 segments for gamma well counting.
Journal of the American College of Cardiology, 1983
Becausethallium-20l uptake relates directly to the amount of viable myocardium and nutrient blood... more Becausethallium-20l uptake relates directly to the amount of viable myocardium and nutrient blood flow, the potential for exercise scintigraphy to predict response to coronary revascularization surgery was investigated in 47 consecutive patients. All patients underwent thallium-201 scintigraphy and coronary angiography at a mean (± standard deviation) of 4.3 ± 3.1 weeks before and 7.5 ± 1.6 weeks after surgery. Thallium uptake and washout were computer-quantified and each of six segments was defined as normal, showing total or partial redistribution or a persistent defect. Persistent defects were further classified according to the percent reduction in regional thallium activity; PD 25 -50 denoted a 25 to 50% constant reduction in relative thallium activity and PD> 50 denoted a greater than 50% reduction. Of 82 segments with total redistribution before surgery, 76 (93%) showed normal thallium uptake and washout postoperatively, versus only 16 (73%) of 22 with partial redistribution (probability [p] = 0.01). Preoperative ventriculography revealed that 95% ofthe segments with total redistribution had preserved wall motion, versus only 74% of those with partial redistribution (p =0.01).
Journal of the American College of Cardiology, 1997
The purpose of this study was to determine how frequently and for what reasons the addition of el... more The purpose of this study was to determine how frequently and for what reasons the addition of electrocardiographically gated technetium-99m (Tc-99m) sestamibi single-photon emission computed tomographic (SPECT) images add value to nongated SPECT perfusion images. Electrocardiographic gating of Tc-99m sestamibi SPECT images permits assessment of regional and global left ventricular function and may assist in differentiating attenuation artifacts from myocardial scar. A total of 285 consecutive patients (143 women and 142 men; mean age 57.6 +/- 11.5 years) underwent gated SPECT Tc-99m sestamibi imaging (212 with exercise, 63 with dipyridamole and 10 with dobutamine). The conventional stress and rest tomograms were interpreted first by means of a 14-segment scoring system, and then the studies were reinterpreted while the gated images were viewed. In the total group of 285 patients, the number of "borderline" interpretations was reduced from 89 to 29. In the 137 patients with a < or = 10% pretest likelihood of coronary artery disease, the addition of gated images added significantly to the percentage of interpretations that were designated "normal" (74% [101 of 137] vs. 93% [127 of 137], p < 0.0001), due to a reduction in borderline normal and borderline abnormal readings. In 49 patients with a previous infarction or recent angiography with > or = 70% stenosis, or both, the addition of gated images changed the percentage of "abnormal" scan interpretations from 78% (38 of 49) to 92% (45 of 49). This result was not significant (p = 0.09, two-tailed), but the trend was toward a greater number of unequivocal abnormal interpretations in this subgroup. The addition of electrocardiographically gated Tc-99m sestamibi SPECT images to the reading of stress and rest perfusion images alone resulted in shifting the final scan interpretations to a more normal designation in patients with a low pretest likelihood of coronary artery disease, and to more abnormal defects consistent with coronary artery disease in patients with known coronary artery disease. The number of "borderline normal" and "borderline abnormal" interpretations are significantly reduced when gated SPECT images are interpreted simultaneously with stress and rest perfusion images.
Journal of the American College of Cardiology, 2003
Journal of the American College of Cardiology, 2002
The study was done to determine the effects of propranolol, enalaprilat, verapamil, and caffeine ... more The study was done to determine the effects of propranolol, enalaprilat, verapamil, and caffeine on the vasodilatory properties of the adenosine A(2A)-receptor agonist ATL-146e (ATL). ATL is a new adenosine A(2A)-receptor agonist proposed as a vasodilator for myocardial stress perfusion imaging. Beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium blockers are commonly used for the treatment of coronary artery disease (CAD), and their effect on ATL-mediated vasodilation is unknown. Dietary intake of caffeine is also common. In 19 anesthetized, open-chest dogs, hemodynamic responses to bolus injections of ATL (1.0 microg/kg) and adenosine (60 microg/kg) were recorded before and after administration of propranolol (1.0 mg/kg, ATL only), enalaprilat (0.3 mg/kg, ATL only), caffeine (5.0 mg/kg, ATL only), and verapamil (0.2 mg/kg bolus, ATL and adenosine). Neither propranolol nor enalaprilat attenuated the ATL-mediated vasodilation (225 +/- 86% and 237 +/- 67% increase, respectively, p = NS vs. control). Caffeine had an inhibitory effect (97 +/- 28% increase, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05 vs. control). Verapamil blunted both ATL- and adenosine-induced vasodilation (63 +/- 20% and 35 +/- 7%, respectively, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05 vs. baseline), and also inhibited the vasodilation induced by the adenosine triphosphate-sensitive potassium (K(ATP)) channel activator pinacidil. Beta-blockers and ACE inhibitors do not reduce the maximal coronary flow response to adenosine A(2A)-agonists, whereas verapamil attenuated this vasodilation through inhibition of K(ATP) channels. The inhibitory effect of verapamil and K(ATP) channel inhibitors like glybenclamide on pharmacologic stress using adenosine or adenosine A(2A)-receptor agonists should be evaluated in the clinical setting to determine their potential for reducing the sensitivity of CAD detection with perfusion imaging.
Journal of the American College of Cardiology, 2011
Journal of the American College of Cardiology, 2003
We hypothesized that fractional flow reserve (FFR) of an infarct-related artery (IRA) early after... more We hypothesized that fractional flow reserve (FFR) of an infarct-related artery (IRA) early after myocardial infarction (MI) identifies inducible ischemia on noninvasive imaging. BACKGROUND Early after MI, IRAs frequently have angiographically indeterminant lesions. Whether FFR can detect reversible perfusion defects early after MI when dynamic microvascular abnormalities are present is not known.
Journal of the American College of Cardiology, 2000
Journal of the American College of Cardiology, 2002
Journal of Nuclear Cardiology, 2012
This study examined short-term cardiac catheterization rates and medication changes after cardiac... more This study examined short-term cardiac catheterization rates and medication changes after cardiac imaging.
Journal of Nuclear Cardiology, 2004
Journal of Nuclear Cardiology, 2006
Technetium 99m N-DBODC5 is a new myocardial perfusion tracer shown to exhibit high heart uptake a... more Technetium 99m N-DBODC5 is a new myocardial perfusion tracer shown to exhibit high heart uptake and rapid liver clearance in normal rats. The objectives of this canine study were (1) to compare the organ biodistribution and myocardial uptake, washout, and redistribution kinetics of Tc-99m N-DBODC5 with Tc-99m sestamibi over a period of 3 hours in a more clinically relevant large animal species and (2) to compare the myocardial uptake of Tc-99m N-DBODC5 with thallium 201 when co-injected during vasodilator stress in dogs with coronary stenoses. At peak adenosine-induced hyperemia, 10 dogs with critical left anterior descending artery stenoses received either Tc-99m N-DBODC5 (n = 6) or Tc-99m sestamibi (n = 4) and microspheres, followed by serial imaging and blood sampling over a period of 3 hours. Another 14 dogs with either critical (n = 7) or mild (n = 7) left anterior descending artery stenoses underwent simultaneous injection of Tc-99m N-DBODC5, Tl-201, and microspheres during peak vasodilator stress. Like sestamibi, Tc-99m N-DBODC5 showed good myocardial uptake with slow washout and minimal redistribution over a period of 3 hours (P = not significant); however, Tc-99m N-DBODC5 cleared more rapidly from the liver (heart-lung ratio at 30 minutes, 0.92+/-0.11 versus 0.51 +/- 0.05; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). When injected during hyperemic flow, the myocardial extraction plateau for Tc-99m N-DBODC5 was lower than that for Tl-201 and was intermediate between Tc-99m sestamibi and Tc-99m tetrofosmin. Excellent organ biodistribution and myocardial uptake and clearance kinetic properties, combined with rapid liver clearance and a favorable flow-extraction relationship, make Tc-99m N-DBODC5 a very promising new myocardial perfusion imaging agent.