Eliana Reyes - Academia.edu (original) (raw)

Papers by Eliana Reyes

Research paper thumbnail of Procedure guidelines for radionuclide myocardial perfusion imaging

Research paper thumbnail of 1. Comparison of nurse and doctor supervised stress testing in the setting of radionuclide myocardial perfusion imaging

Nuclear Medicine Communications, 2002

... Reyes, E.1; Rahman, S.1; Loong, CY1; Bunce, N.2; Latus, K.1; Ozerovitch, L.1; Anagnostopoulos... more ... Reyes, E.1; Rahman, S.1; Loong, CY1; Bunce, N.2; Latus, K.1; Ozerovitch, L.1; Anagnostopoulos, C.1,3; Underwood, SR1,3. ... Methods: One thousand, two hundred and sixty-one patients were recruited from those referred for MPI between June 2000 and October 2001. ...

Research paper thumbnail of Sixty-four-slice computed tomography coronary angiography compared with myocardial perfusion scintigraphy for the diagnosis of functionally significant coronary stenoses in patients with a low to intermediate likelihood of coronary artery disease

Journal of Nuclear Cardiology, 2008

Background. Multislice computed tomography coronary angiography (CTA) was proposed as a method fo... more Background. Multislice computed tomography coronary angiography (CTA) was proposed as a method for investigating possible coronary artery disease (CAD) in patients who present with chest pain but with a low to intermediate likelihood of CAD. Sixty-four-channel CTA was compared prospectively with 99mTc-tetrofosmin myocardial perfusion scintigraphy (MPS) (as the gold standard in the detection of flow-limiting stenoses) for the detection of functionally significant CAD. Methods and Results. Fifty-two consecutive symptomatic patients with a low to intermediate likelihood of coronary artery disease, and who were referred for MPS, also underwent CTA. The CTA datasets were analyzed by two experienced observers who were blinded to the MPS data, and coronary artery segments were reported as <50%, 50% to 69%, 70% to 99% stenoses, or occluded. The MPS images were similarly analyzed for inducible perfusion abnormalities, and coronary territories were identified. At the patient level, agreement between CTA and MPS for CTA lesions at ≥50% was 87% (sensitivity, 100%; specificity, 84%; positive predictive value, 50%; negative predictive value, 100%). For CTA lesions, agreement at ≥70% was 96% (sensitivity, 86%; specificity, 98%; positive predictive value, 86%; negative predictive value, 98%). Conclusions. In patients with a low to intermediate likelihood of CAD, there is good correlation between MPS and CTA for the detection of functionally significant coronary artery stenoses when CTA detects a narrowing of ≥70% severity. Computed tomography coronary angiography stenoses of 70% should be used to determine functional significance, and not 50%, as is the usual practice at present.

Research paper thumbnail of Effect of body mass index on the efficacy, side effect profile, and plasma concentration of fixed-dose regadenoson for myocardial perfusion imaging

Journal of Nuclear Cardiology

Background There are limited data on the effect of body mass index (BMI) on the actions of fixed-... more Background There are limited data on the effect of body mass index (BMI) on the actions of fixed-dose regadenoson. The purpose of this study was to determine the effect of BMI on the efficacy, side effects, and plasma concentration of regadenoson for Myocardial Perfusion Imaging (MPI). Methods and Results The study included 2,015 subjects from the ADVANCE MPI trials. Initial adenosine MPI was followed by randomization to regadenoson (400-μg bolus injection) or adenosine (6-minute infusion) MPI. Subjects were classified according to BMI into six categories from underweight (<20 kg/m2) to extremely obese (≥40 kg/m2). PK modeling was used to predict the effect of BMI on plasma regadenoson concentration (PRC). Adenosine-regadenoson agreement rates for the presence and extent of reversibility were similar across BMI categories (P > .05). The incidence of side effects was also similar across BMIs (P ≥ .06). Subjects were less likely to feel very or extremely uncomfortable after regadenoson vs adenosine in all groups with BMI ≥ 25 kg/m2, but this trend was not statistically significant in subjects with BMI 20-24 kg/m2 (P > .05). PRC was inversely related to BMI with 19% higher PRC in the underweight and 36% lower PRC in the extremely obese compared with a normal weight subject. Conclusions BMI does not alter the efficacy of regadenoson MPI despite lower PRC in high BMI subjects, or its side effect profile despite higher PRC in low BMI subjects. Regadenoson is better tolerated than adenosine but this benefit seems to lose statistical significance in subjects with BMI < 25 kg/m2.

Research paper thumbnail of Procedure Guidelines for Radionuclide Myocardial Perfusion Imaging

Research paper thumbnail of Comparison of 64-slice cardiac computed tomography with myocardial perfusion scintigraphy for assessment of global and regional myocardial function and infarction in patients with low to intermediate likelihood of coronary artery disease

Journal of Nuclear Cardiology, 2008

Background. Cardiac computed tomography (CCT) has the potential to assess both coronary anatomy a... more Background. Cardiac computed tomography (CCT) has the potential to assess both coronary anatomy and ventricular function in a single study. We examined the agreement between CCT and myocardial perfusion scintigraphy (MPS) for the assessment of global and regional ventricular function. Methods and Results. Research CCT was performed in 52 patients with a low to intermediate likelihood of coronary artery disease referred for MPS. Left ventricular enddiastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction (LVEF), and myocardial wall motion and thickening were compared between techniques. In addition, myocardial contrast attenuation on CCT was compared with radiotracer uptake on MPS. LVEF values agreed well (mean difference, 4.1%; SD, 15.13%), but CCT left ventricular end-diastolic volume was greater compared with MPS (mean difference, 46.0 mL; SD, 33.34 mL) (P<.001). There was moderate agreement for segmental myocardial motion and thickening, with κ values of 0.57 (95% confidence interval, 0.51–0.63) and 0.47 (95% confidence interval, 0.41–0.53), respectively. Seventeen patients had hypoattenuation in at least 1 myocardial segment on CCT. Three of four patients with concomitant abnormalities of wall motion and thickening on CCT had infarction in the same territory on MPS. Conclusions. There was good agreement for LVEF between CCT and MPS but myocardial volumes differed, and these modalities cannot be used interchangeably. Mild abnormalities of regional function are detected more commonly by CCT than by MPS. Myocardial hypoattenuation on CCT is highly specific for myocardial infarction when associated with reduction of systolic wall thickening and regional wall motion abnormality.

Research paper thumbnail of A comparison of Tl201, Tc99m sestamibi, and Tc99m tetrofosmin myocardial perfusion scintigraphy in patients with mild to moderate coronary stenosis

Journal of Nuclear Cardiology, 2006

Background Thallium 201, technetium 99m sestamibi (MIBI), and Tc-99m tetrofosmin differ in their ... more Background Thallium 201, technetium 99m sestamibi (MIBI), and Tc-99m tetrofosmin differ in their myocardial uptake characteristics. This may make the technetium tracers less sensitive for detecting mild to moderate coronary stenosis. Methods and Results We identified 163 patients with angiographic mild to moderate stenosis (50%-89%) and coexistent severe disease (88/163 patients) from a previous study of patients who received either thallium, MIBI, or tetrofosmin for myocardial perfusion scintigraphy. Summed segmental uptake scores were used to assess myocardial perfusion of territories supplied by the mildly to moderately stenotic vessels. Mean (± SD) summed stress uptake scores in the left anterior descending artery territory were 21.4 ± 3.8, 21.6 ± 4.2, and 22.1 ± 2.3 for thallium, MIBI, and tetrofosmin, respectively (P = .7); mean summed difference uptake scores were 1.2 ± 1.8, 1.1 ± 1.9, and 1.0 ± 1.1, respectively (P = .8). In the non-left anterior descending artery territory, mean summed stress uptake scores were 32.5 ± 6.3, 34.0 ± 6.3, and 34.5 ± 4.7 for thallium, MIBI, and tetrofosmin, respectively (P = .4), whereas mean summed difference scores were 1.9 ± 2.6, 1.7 ± 2.2, and 1.7 ± 2.3, respectively (P = .9). Conclusion There were no significant differences between the tracers for the summed uptake scores. This suggests that the 3 tracers are comparable in clinical practice for assessing the extent and severity of perfusion abnormalities arising from mild to moderate coronary artery stenosis, especially in the presence of coexistent severe disease.

Research paper thumbnail of Does attenuation corrected SPECT improve the detection of viable myocardium

Nuclear Medicine Communications, 2004

Background: Assessment of regional heart wall deformation can provide quantitative information re... more Background: Assessment of regional heart wall deformation can provide quantitative information regarding ventricular wall function in congestive heart failure. In particular, mechanisms involving the progression of cardiac hypertrophy are being evaluated in rat models using measures of LVEF and 3D left ventricular deformation. Methods: PET data were acquired using the microPET II. A dose of 1 mCi of F-18-FDG was injected into normotensive Wistar Kyoto (WKY) rats and the same dose was injected into spontaneous hypertensive rats (SHR). The rats ranged in weight from 200 to 350 grams. For imaging a gated acquisition is used for one hour acquiring eight frames over the cardiac cycle of approximately 500 -900 million total counts. LVEF was calculated using a method that does not require the identification of the endocardial edge of the LV and was shown to work well for small hearts in clinical application. Also, left ventricular deformation was quantified by warping analysis of the gated microPET images, which allows for the extraction of strain information from sequences of images of deforming tissue. The warping approach uses the end-systolic image data sets as a reference configuration (template) and uses the end-diastole image data sets as the deformed configuration (target). The warping technique produces a body force from the intensity differences between the images. This force is applied to a FE representation of the template image, causing it to deform into registration with the target image. Results: At the age of 5 months, the results indicated that the average circumferential strain was 15% larger for the LV of a normotensive rat than the LV of a hypertensive rat, whereas there were a 13% difference between the LVEF. While the strain distributions were similar for each model, the magnitude of the circumferential strains were lower in the spontaneous hypertensive rat models.

Research paper thumbnail of Significant inducible perfusion abnormality in an asymptomatic patient with hypertrophic cardiomyopathy demonstrated by radionuclide myocardial perfusion imaging

Research paper thumbnail of Side effect profile and tolerability of adenosine myocardial perfusion scintigraphy in patients with mild asthma or chronic obstructive pulmonary disease

Journal of Nuclear Cardiology, 2007

Background Adenosine may cause bronchoconstriction in subjects with asthma or chronic obstructive... more Background Adenosine may cause bronchoconstriction in subjects with asthma or chronic obstructive pulmonary disease (COPD). Recent evidence suggests that this effect may be dependent on the severity of disease. This study investigates the tolerability of adenosine stress in patients with mild asthma or COPD undergoing myocardial perfusion scintigraphy. Methods and Results In this case-control study patients with known or suspected mild asthma or COPD were pretreated with an inhaled β2-adrenergic agonist and adenosine titrated up to the maximal dose of 140 μg·kg−1·min−1 over a period of 6 minutes. The occurrence of side effects and test tolerability were compared between the airway disease group and 72 control subjects. Of 1261 patients, 124 had known or suspected airway disease; of these, 72 (58%) were suitable for adenosine stress. The proportion of tests completed as per protocol in the asthma/COPD group was similar to that of control subjects (93% vs 100%, P=.06). Dyspnea (n=38 [53%] in asthma/COPD group vs n=25 [35%] in control group, P=.03) and chest pain (n=14 [19%] in asthma/COPD group vs n=16 [22%] in control group, P=.7) were the most common side effects, and these were mostly mild and well tolerated. Bronchospasm occurred in 5 patients with asthma/COPD but reverted shortly after discontinuation of the adenosine infusion. Aminophylline was not required in any case. Conclusions A stepwise 6-minute adenosine infusion with prophylactic β2-adrenergic agonist is safe and well tolerated in patients with mild asthma or COPD.

Research paper thumbnail of 61. FDG gamma camera PET in the detection of viable myocardium in chronic ischaemic left ventricular dysfunction

Nuclear Medicine Communications, 2003

Research paper thumbnail of Attenuation of Adenosine-Induced Myocardial Perfusion Heterogeneity by Atenolol and Other Cardioselective Adrenoceptor Blockers: A Crossover Myocardial Perfusion Imaging Study

Journal of Nuclear Medicine, 2010

Little is known about the effect of chronic beta-blockade on adenosine actions. We sought to inve... more Little is known about the effect of chronic beta-blockade on adenosine actions. We sought to investigate the effect of oral beta-blockers on the presence, extent, and severity of myocardial perfusion abnormality induced by adenosine in patients with coronary artery disease. In this crossover study, 45 male patients with coronary artery disease on beta-blocker therapy with atenolol, bisoprolol, or metoprolol underwent adenosine myocardial perfusion imaging both on and off beta-blockade in a random order on separate days. Myocardial perfusion was assessed both qualitatively and quantitatively. Hemodynamic response, image analysis, and sensitivity for the detection of coronary stenosis (&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;gt;or=50% luminal diameter reduction on x-ray coronary angiography) were compared between the on and off beta-blocker studies. Rate pressure product both at baseline and at peak adenosine infusion decreased by 23% +/- 15% and 21% +/- 18%, respectively, after beta-blockade (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;lt; 0.001 for all). The median (interquartile range) summed difference score, a measure of defect reversibility, and quantitative defect size were both significantly lower after beta-blockade (median, 7.0 [interquartile range, 2.0-9.5] vs. median, 5.0 [interquartile range, 0-8.0], P = 0.002; and quantitative defect size, 18% [interquartile range, 9%-34%] vs. quantitative defect size, 6% [interquartile range, 0%-19%], 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;lt; 0.001, respectively). The overall sensitivity for the detection of coronary stenosis decreased from 0.76 (95% confidence interval, 0.65-0.88) to 0.58 (95% confidence interval, 0.45-0.71) after beta-blockade (P = 0.03). beta-blockade causes a small but significant reduction in the extent and severity of perfusion abnormality by adenosine. This may reduce the diagnostic sensitivity of adenosine myocardial perfusion imaging for the detection of flow-limiting coronary stenosis.

Research paper thumbnail of High-Dose Adenosine Overcomes the Attenuation of Myocardial Perfusion Reserve Caused by Caffeine

Journal of The American College of Cardiology, 2008

We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-media... more We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation.

Research paper thumbnail of Acute myocardial infarction during adenosine myocardial perfusion imaging

Journal of Nuclear Cardiology, 2004

Case history. A 71-year-old man with chronic atrial fibrillation and no previous myocardial infar... more Case history. A 71-year-old man with chronic atrial fibrillation and no previous myocardial infarction (MI) was referred for myocardial perfusion scintigraphy. He had an 8-month history of increasing exertional chest pain and breathlessness. His medication included metoprolol, isosorbide mononitrate, warfarin, and digoxin. Stress was performed with an intravenous infusion of adenosine at 140 g · kg Ϫ1 · min Ϫ1 . At 3 minutes of adenosine infusion, he developed severe chest pain associated with 3-mm horizontal ST-segment depression

Research paper thumbnail of REFERENCIAS

Yo, DAMELIS MARGARITA VASQUEZ, venezolano(a), mayor de edad, titular de la Cedula de Identidad Nº... more Yo, DAMELIS MARGARITA VASQUEZ, venezolano(a), mayor de edad, titular de la Cedula de Identidad Nº V-9.922.748, domiciliado(a) en la calle La Romana S/N, sector Colombia, El Socorro; Edo. Guárico; por medio de la presente declaro que conozco de vista, trato y comunicación a el (la) ciudadano(a): RAMONA ELIANA REYES, venezolano(a), mayor de edad, titular de la Cedula de Identidad Nº V-15.823.232, domiciliado(a) en la calle Hernández Romero # 183, sector Colombia, El Socorro; Edo. Guárico, el (la) cual es una persona seria, honesta, responsable y de conducta intachable, por lo cual no dudo en recomendarlo(a) en virtud de la razón antes expuesta. Referencia que expido en El Socorro, a los 25 días del mes de Noviembre del año 2013. DAMELIS MARGARITA VASQUEZ C.I. V-9.922.748 Telf.:0414-2946318 SRES: BANCO DE VENEZUELA

Research paper thumbnail of Procedure guidelines for radionuclide myocardial perfusion imaging

Research paper thumbnail of 1. Comparison of nurse and doctor supervised stress testing in the setting of radionuclide myocardial perfusion imaging

Nuclear Medicine Communications, 2002

... Reyes, E.1; Rahman, S.1; Loong, CY1; Bunce, N.2; Latus, K.1; Ozerovitch, L.1; Anagnostopoulos... more ... Reyes, E.1; Rahman, S.1; Loong, CY1; Bunce, N.2; Latus, K.1; Ozerovitch, L.1; Anagnostopoulos, C.1,3; Underwood, SR1,3. ... Methods: One thousand, two hundred and sixty-one patients were recruited from those referred for MPI between June 2000 and October 2001. ...

Research paper thumbnail of Sixty-four-slice computed tomography coronary angiography compared with myocardial perfusion scintigraphy for the diagnosis of functionally significant coronary stenoses in patients with a low to intermediate likelihood of coronary artery disease

Journal of Nuclear Cardiology, 2008

Background. Multislice computed tomography coronary angiography (CTA) was proposed as a method fo... more Background. Multislice computed tomography coronary angiography (CTA) was proposed as a method for investigating possible coronary artery disease (CAD) in patients who present with chest pain but with a low to intermediate likelihood of CAD. Sixty-four-channel CTA was compared prospectively with 99mTc-tetrofosmin myocardial perfusion scintigraphy (MPS) (as the gold standard in the detection of flow-limiting stenoses) for the detection of functionally significant CAD. Methods and Results. Fifty-two consecutive symptomatic patients with a low to intermediate likelihood of coronary artery disease, and who were referred for MPS, also underwent CTA. The CTA datasets were analyzed by two experienced observers who were blinded to the MPS data, and coronary artery segments were reported as <50%, 50% to 69%, 70% to 99% stenoses, or occluded. The MPS images were similarly analyzed for inducible perfusion abnormalities, and coronary territories were identified. At the patient level, agreement between CTA and MPS for CTA lesions at ≥50% was 87% (sensitivity, 100%; specificity, 84%; positive predictive value, 50%; negative predictive value, 100%). For CTA lesions, agreement at ≥70% was 96% (sensitivity, 86%; specificity, 98%; positive predictive value, 86%; negative predictive value, 98%). Conclusions. In patients with a low to intermediate likelihood of CAD, there is good correlation between MPS and CTA for the detection of functionally significant coronary artery stenoses when CTA detects a narrowing of ≥70% severity. Computed tomography coronary angiography stenoses of 70% should be used to determine functional significance, and not 50%, as is the usual practice at present.

Research paper thumbnail of Effect of body mass index on the efficacy, side effect profile, and plasma concentration of fixed-dose regadenoson for myocardial perfusion imaging

Journal of Nuclear Cardiology

Background There are limited data on the effect of body mass index (BMI) on the actions of fixed-... more Background There are limited data on the effect of body mass index (BMI) on the actions of fixed-dose regadenoson. The purpose of this study was to determine the effect of BMI on the efficacy, side effects, and plasma concentration of regadenoson for Myocardial Perfusion Imaging (MPI). Methods and Results The study included 2,015 subjects from the ADVANCE MPI trials. Initial adenosine MPI was followed by randomization to regadenoson (400-μg bolus injection) or adenosine (6-minute infusion) MPI. Subjects were classified according to BMI into six categories from underweight (<20 kg/m2) to extremely obese (≥40 kg/m2). PK modeling was used to predict the effect of BMI on plasma regadenoson concentration (PRC). Adenosine-regadenoson agreement rates for the presence and extent of reversibility were similar across BMI categories (P > .05). The incidence of side effects was also similar across BMIs (P ≥ .06). Subjects were less likely to feel very or extremely uncomfortable after regadenoson vs adenosine in all groups with BMI ≥ 25 kg/m2, but this trend was not statistically significant in subjects with BMI 20-24 kg/m2 (P > .05). PRC was inversely related to BMI with 19% higher PRC in the underweight and 36% lower PRC in the extremely obese compared with a normal weight subject. Conclusions BMI does not alter the efficacy of regadenoson MPI despite lower PRC in high BMI subjects, or its side effect profile despite higher PRC in low BMI subjects. Regadenoson is better tolerated than adenosine but this benefit seems to lose statistical significance in subjects with BMI < 25 kg/m2.

Research paper thumbnail of Procedure Guidelines for Radionuclide Myocardial Perfusion Imaging

Research paper thumbnail of Comparison of 64-slice cardiac computed tomography with myocardial perfusion scintigraphy for assessment of global and regional myocardial function and infarction in patients with low to intermediate likelihood of coronary artery disease

Journal of Nuclear Cardiology, 2008

Background. Cardiac computed tomography (CCT) has the potential to assess both coronary anatomy a... more Background. Cardiac computed tomography (CCT) has the potential to assess both coronary anatomy and ventricular function in a single study. We examined the agreement between CCT and myocardial perfusion scintigraphy (MPS) for the assessment of global and regional ventricular function. Methods and Results. Research CCT was performed in 52 patients with a low to intermediate likelihood of coronary artery disease referred for MPS. Left ventricular enddiastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction (LVEF), and myocardial wall motion and thickening were compared between techniques. In addition, myocardial contrast attenuation on CCT was compared with radiotracer uptake on MPS. LVEF values agreed well (mean difference, 4.1%; SD, 15.13%), but CCT left ventricular end-diastolic volume was greater compared with MPS (mean difference, 46.0 mL; SD, 33.34 mL) (P<.001). There was moderate agreement for segmental myocardial motion and thickening, with κ values of 0.57 (95% confidence interval, 0.51–0.63) and 0.47 (95% confidence interval, 0.41–0.53), respectively. Seventeen patients had hypoattenuation in at least 1 myocardial segment on CCT. Three of four patients with concomitant abnormalities of wall motion and thickening on CCT had infarction in the same territory on MPS. Conclusions. There was good agreement for LVEF between CCT and MPS but myocardial volumes differed, and these modalities cannot be used interchangeably. Mild abnormalities of regional function are detected more commonly by CCT than by MPS. Myocardial hypoattenuation on CCT is highly specific for myocardial infarction when associated with reduction of systolic wall thickening and regional wall motion abnormality.

Research paper thumbnail of A comparison of Tl201, Tc99m sestamibi, and Tc99m tetrofosmin myocardial perfusion scintigraphy in patients with mild to moderate coronary stenosis

Journal of Nuclear Cardiology, 2006

Background Thallium 201, technetium 99m sestamibi (MIBI), and Tc-99m tetrofosmin differ in their ... more Background Thallium 201, technetium 99m sestamibi (MIBI), and Tc-99m tetrofosmin differ in their myocardial uptake characteristics. This may make the technetium tracers less sensitive for detecting mild to moderate coronary stenosis. Methods and Results We identified 163 patients with angiographic mild to moderate stenosis (50%-89%) and coexistent severe disease (88/163 patients) from a previous study of patients who received either thallium, MIBI, or tetrofosmin for myocardial perfusion scintigraphy. Summed segmental uptake scores were used to assess myocardial perfusion of territories supplied by the mildly to moderately stenotic vessels. Mean (± SD) summed stress uptake scores in the left anterior descending artery territory were 21.4 ± 3.8, 21.6 ± 4.2, and 22.1 ± 2.3 for thallium, MIBI, and tetrofosmin, respectively (P = .7); mean summed difference uptake scores were 1.2 ± 1.8, 1.1 ± 1.9, and 1.0 ± 1.1, respectively (P = .8). In the non-left anterior descending artery territory, mean summed stress uptake scores were 32.5 ± 6.3, 34.0 ± 6.3, and 34.5 ± 4.7 for thallium, MIBI, and tetrofosmin, respectively (P = .4), whereas mean summed difference scores were 1.9 ± 2.6, 1.7 ± 2.2, and 1.7 ± 2.3, respectively (P = .9). Conclusion There were no significant differences between the tracers for the summed uptake scores. This suggests that the 3 tracers are comparable in clinical practice for assessing the extent and severity of perfusion abnormalities arising from mild to moderate coronary artery stenosis, especially in the presence of coexistent severe disease.

Research paper thumbnail of Does attenuation corrected SPECT improve the detection of viable myocardium

Nuclear Medicine Communications, 2004

Background: Assessment of regional heart wall deformation can provide quantitative information re... more Background: Assessment of regional heart wall deformation can provide quantitative information regarding ventricular wall function in congestive heart failure. In particular, mechanisms involving the progression of cardiac hypertrophy are being evaluated in rat models using measures of LVEF and 3D left ventricular deformation. Methods: PET data were acquired using the microPET II. A dose of 1 mCi of F-18-FDG was injected into normotensive Wistar Kyoto (WKY) rats and the same dose was injected into spontaneous hypertensive rats (SHR). The rats ranged in weight from 200 to 350 grams. For imaging a gated acquisition is used for one hour acquiring eight frames over the cardiac cycle of approximately 500 -900 million total counts. LVEF was calculated using a method that does not require the identification of the endocardial edge of the LV and was shown to work well for small hearts in clinical application. Also, left ventricular deformation was quantified by warping analysis of the gated microPET images, which allows for the extraction of strain information from sequences of images of deforming tissue. The warping approach uses the end-systolic image data sets as a reference configuration (template) and uses the end-diastole image data sets as the deformed configuration (target). The warping technique produces a body force from the intensity differences between the images. This force is applied to a FE representation of the template image, causing it to deform into registration with the target image. Results: At the age of 5 months, the results indicated that the average circumferential strain was 15% larger for the LV of a normotensive rat than the LV of a hypertensive rat, whereas there were a 13% difference between the LVEF. While the strain distributions were similar for each model, the magnitude of the circumferential strains were lower in the spontaneous hypertensive rat models.

Research paper thumbnail of Significant inducible perfusion abnormality in an asymptomatic patient with hypertrophic cardiomyopathy demonstrated by radionuclide myocardial perfusion imaging

Research paper thumbnail of Side effect profile and tolerability of adenosine myocardial perfusion scintigraphy in patients with mild asthma or chronic obstructive pulmonary disease

Journal of Nuclear Cardiology, 2007

Background Adenosine may cause bronchoconstriction in subjects with asthma or chronic obstructive... more Background Adenosine may cause bronchoconstriction in subjects with asthma or chronic obstructive pulmonary disease (COPD). Recent evidence suggests that this effect may be dependent on the severity of disease. This study investigates the tolerability of adenosine stress in patients with mild asthma or COPD undergoing myocardial perfusion scintigraphy. Methods and Results In this case-control study patients with known or suspected mild asthma or COPD were pretreated with an inhaled β2-adrenergic agonist and adenosine titrated up to the maximal dose of 140 μg·kg−1·min−1 over a period of 6 minutes. The occurrence of side effects and test tolerability were compared between the airway disease group and 72 control subjects. Of 1261 patients, 124 had known or suspected airway disease; of these, 72 (58%) were suitable for adenosine stress. The proportion of tests completed as per protocol in the asthma/COPD group was similar to that of control subjects (93% vs 100%, P=.06). Dyspnea (n=38 [53%] in asthma/COPD group vs n=25 [35%] in control group, P=.03) and chest pain (n=14 [19%] in asthma/COPD group vs n=16 [22%] in control group, P=.7) were the most common side effects, and these were mostly mild and well tolerated. Bronchospasm occurred in 5 patients with asthma/COPD but reverted shortly after discontinuation of the adenosine infusion. Aminophylline was not required in any case. Conclusions A stepwise 6-minute adenosine infusion with prophylactic β2-adrenergic agonist is safe and well tolerated in patients with mild asthma or COPD.

Research paper thumbnail of 61. FDG gamma camera PET in the detection of viable myocardium in chronic ischaemic left ventricular dysfunction

Nuclear Medicine Communications, 2003

Research paper thumbnail of Attenuation of Adenosine-Induced Myocardial Perfusion Heterogeneity by Atenolol and Other Cardioselective Adrenoceptor Blockers: A Crossover Myocardial Perfusion Imaging Study

Journal of Nuclear Medicine, 2010

Little is known about the effect of chronic beta-blockade on adenosine actions. We sought to inve... more Little is known about the effect of chronic beta-blockade on adenosine actions. We sought to investigate the effect of oral beta-blockers on the presence, extent, and severity of myocardial perfusion abnormality induced by adenosine in patients with coronary artery disease. In this crossover study, 45 male patients with coronary artery disease on beta-blocker therapy with atenolol, bisoprolol, or metoprolol underwent adenosine myocardial perfusion imaging both on and off beta-blockade in a random order on separate days. Myocardial perfusion was assessed both qualitatively and quantitatively. Hemodynamic response, image analysis, and sensitivity for the detection of coronary stenosis (&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;gt;or=50% luminal diameter reduction on x-ray coronary angiography) were compared between the on and off beta-blocker studies. Rate pressure product both at baseline and at peak adenosine infusion decreased by 23% +/- 15% and 21% +/- 18%, respectively, after beta-blockade (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;lt; 0.001 for all). The median (interquartile range) summed difference score, a measure of defect reversibility, and quantitative defect size were both significantly lower after beta-blockade (median, 7.0 [interquartile range, 2.0-9.5] vs. median, 5.0 [interquartile range, 0-8.0], P = 0.002; and quantitative defect size, 18% [interquartile range, 9%-34%] vs. quantitative defect size, 6% [interquartile range, 0%-19%], 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;lt; 0.001, respectively). The overall sensitivity for the detection of coronary stenosis decreased from 0.76 (95% confidence interval, 0.65-0.88) to 0.58 (95% confidence interval, 0.45-0.71) after beta-blockade (P = 0.03). beta-blockade causes a small but significant reduction in the extent and severity of perfusion abnormality by adenosine. This may reduce the diagnostic sensitivity of adenosine myocardial perfusion imaging for the detection of flow-limiting coronary stenosis.

Research paper thumbnail of High-Dose Adenosine Overcomes the Attenuation of Myocardial Perfusion Reserve Caused by Caffeine

Journal of The American College of Cardiology, 2008

We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-media... more We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation.

Research paper thumbnail of Acute myocardial infarction during adenosine myocardial perfusion imaging

Journal of Nuclear Cardiology, 2004

Case history. A 71-year-old man with chronic atrial fibrillation and no previous myocardial infar... more Case history. A 71-year-old man with chronic atrial fibrillation and no previous myocardial infarction (MI) was referred for myocardial perfusion scintigraphy. He had an 8-month history of increasing exertional chest pain and breathlessness. His medication included metoprolol, isosorbide mononitrate, warfarin, and digoxin. Stress was performed with an intravenous infusion of adenosine at 140 g · kg Ϫ1 · min Ϫ1 . At 3 minutes of adenosine infusion, he developed severe chest pain associated with 3-mm horizontal ST-segment depression

Research paper thumbnail of REFERENCIAS

Yo, DAMELIS MARGARITA VASQUEZ, venezolano(a), mayor de edad, titular de la Cedula de Identidad Nº... more Yo, DAMELIS MARGARITA VASQUEZ, venezolano(a), mayor de edad, titular de la Cedula de Identidad Nº V-9.922.748, domiciliado(a) en la calle La Romana S/N, sector Colombia, El Socorro; Edo. Guárico; por medio de la presente declaro que conozco de vista, trato y comunicación a el (la) ciudadano(a): RAMONA ELIANA REYES, venezolano(a), mayor de edad, titular de la Cedula de Identidad Nº V-15.823.232, domiciliado(a) en la calle Hernández Romero # 183, sector Colombia, El Socorro; Edo. Guárico, el (la) cual es una persona seria, honesta, responsable y de conducta intachable, por lo cual no dudo en recomendarlo(a) en virtud de la razón antes expuesta. Referencia que expido en El Socorro, a los 25 días del mes de Noviembre del año 2013. DAMELIS MARGARITA VASQUEZ C.I. V-9.922.748 Telf.:0414-2946318 SRES: BANCO DE VENEZUELA