PubMed Health⌕ Search

Biomedical subjects

Erick Alexánderson

Publications and source records attributed to Erick Alexánderson.

18 recordsLinked to original sources
PubMedDate not supplied

Technetium-99m-Sestamibi SPECT myocardial perfusion imaging in patients with complete left bundle branch block.

BACKGROUND: Diagnosis of coronary artery disease (CAD) in patients with left bundle branch block (LBBB) is considered a challenge in cardiology due to low accuracy of noninvasive methods such as basal and exercise stress test. Recently, myocardial perfusion imaging showed attainment of higher sensitivity and specificity. Scintigraphy with thallium-201 has been widely used in these patients. Few have used technetium-99m-Sestamibi and single photon emission computed tomography (SPECT). The aim of the study was to assess the diagnostic value of Tc-99m Sestamibi SPECT myocardial perfusion imaging in patients with complete LBBB. METHODS: We studied 57 consecutive patients with complete LBBB using Tc-99m-Sestamibi SPECT and treadmill or dipyridamole stress to evaluate CAD. Eighteen patients also underwent coronary angiography. Perfusion defects were classified as fixed or reversible. RESULTS: Prevalence of resting perfusion abnormalities in anterior, septal, and apical regions was 51, 56, and 19%, respectively. Sensitivity for detecting >50% left anterior descending artery (LAD) stenosis was 67 and 56% for anterior or septal defects, and 56% for specificity. Apical perfusion abnormality showed 21% sensitivity and 89% specificity. Among six patients with reversibility and who underwent coronary angiography, all had >50% LAD stenosis. CONCLUSIONS: With Tc-99m-MIBI SPECT imaging, prevalence of anteroseptal perfusion abnormalities was >50% in patients with LBBB. The test has moderate sensitivity and specificity for LAD disease. Absence of apical defect is specific for excluding LAD disease. Reversible changes in anteroseptal wall should be considered as an indicator of ischemia in this territory.

Age Factors↗
PubMedDate not supplied

[Correlation between left ventricular ejection fraction assessed by gated SPECT and radionuclide ventriculography in patients with ischemic cardiomyopathy].

BACKGROUND: Recently, the use of Gated SPECT to assess ejection fraction, volumes and ventricular wall motion has been suggested. The aim of this study is to compare the ejection fraction (EF) obtained by Gated SPECT (QGS, Cedars Sinai) with the values obtained through equilibrium ventriculography in patients with ischemic heart disease. METHODS: We studied 50 consecutive patients that were diagnosed by equilibrium radioisotopic ventriculography and Gated SPECT with a dual protocol (TI-201 rest/Tc-99m SestaMIBI stress) using the QGS, Cedars Sinai software. RESULTS: We found a 92% correlation between both tests. In the subgroup analysis, the higher correlation (r = 0.89) was found in group 2, which included patients with moderate ventricular dysfunction (EF 30-50%), whereas, in patients with severe ventricular dysfunction (group 3, EF < 30%), the correlation was lower (r = 0.76) than in group 2, but higher than in patients with EF > 50% (group 1). CONCLUSIONS: There is a good correlation between EF obtained with Gated SPECT and equilibrium ventriculography, regardless of the EF value.

Adult↗
PubMedDate not supplied

[Usefulness of nuclear techniques in the study of myocardial viability].

The assessment of myocardial viability in patients with coronary artery disease and left ventricular dysfunction is of great diagnostic and prognostic value. The identification of myocardial viability, in patients with coronary artery disease and left ventricular dysfunction is useful in risk stratification, for it allows the prediction of a group of patients that may benefit the most from a revascularization procedure. The revascularization of dysfunctional (asinergic) segments showing viability in patients with coronary artery disease and left ventricular dysfunction has been associated to improved survival and New York Heart Association (NYHA) class. An improvement in global as well as in regional left ventricular function has also been described. Currently, several non-invasive imaging techniques have been used to assess myocardial viability, among them, nuclear cardiology methods are the most employed. TI-201 SPECT imaging (stress-redistribution-reinjection) is one of the most commonly used, because of its availability, cost, and correlation with 18-FDG PET studies, which is considered the gold standard among imaging techniques for the detection of myocardial viability. Therefore, if PET is available, it should be used in patients with coronary artery disease and moderate to severe left ventricular dysfunction.

Humans↗
PubMedDate not supplied

[Positron emission tomography (PET): a useful tool for the assessment of cardiac metabolism].

Under normal conditions, myocardial metabolism is based on the oxidation of fatty acids and in a lesser extent carbohydrates. Cardiac function depends upon an adequate supplement of adenosine triphosphate (ATP) by these substrates. However, the main source of energy is susceptible to change upon a various physiologic (exercise) as well as pathologic (ischemia-reperfusion) conditions. Recently, carnitine has gained attention as a modulator of fatty acids and carbohydrates metabolism by means of modifying intramitochondrial Acetyl-CoA/CoA ratio. Disturbances in fatty acids and carbohydrates metabolism in the myocardium have been associated with cardiovascular diseases (chronic ischemic disease, ventricular hypertrophy and dilated cardiomyopathy). The evaluation of cardiac metabolism attains great value regarding diagnosis, treatment and prognosis of these diseases. Currently, positron emission tomography (PET) is one of the preferred methods to evaluate cardiac energy metabolism in clinical practice. In PET images the tracers most commonly used are 11C-palmitate, 11C-acetate y 18Fluoro-2-deoxyglucose (FDG), the first two are employed to assess fatty acids oxidation and FDG is used to evaluate carbohydrates metabolism.

Acetates↗
PubMedDate not supplied

[Myocardial viability, its importance for the therapeutic decision].

Myocardial viability detection is essential in patients with history of myocardial infarction whom develop ventricular dysfunction. Its detection influences the therapeutic decisions and the prognosis. Medical therapy in patients with ventricular dysfunction due to myocardial infarction and myocardial viability has been associated with higher morbidity and mortality rates than revascularization therapy, as well as improvements in the systolic function. Several imaging techniques used in the recognition of myocardial viability are available; these techniques are based on the assessment of the ventricular motion posterior to inotropic agents stimulation or on the demonstration of metabolic activity at the dysfunctional regions. In this study, some important aspects of each technique are reviewed, doing special emphasis in the utility of the Positron Emission Tomography (PET) which has been considered as the "gold standard" in the detection of myocardial viability.

Clinical Protocols↗
PubMedDate not supplied

[Evaluation of coronary flow by means of PET in the Mexican population without coronary artery disease].

UNLABELLED: Coronary artery disease (CAD) represents the principal cause of morbidity and mortality in our environment. Positron emission tomography (PET) is a new technique in our country that allows the assessment of myocardial perfusion and the absolute quantification of the coronary blood flow (CBF) through the utilization of radiotracers using the same criteria employed in conventional nuclear cardiology. CBF normal values have been determined in other populations around the world. No studies in our country assessing in a non-invasive way the CBF have been published before. The quantification of CBF in healthy population is important to establish a standard measure and determine through it, the effects of the many diseases that change the coronary blood flow. The quantification of the CBF, the calculation of coronary blood flow reserve (CFR) and the endothelium dependent vasodilatation index (EDVI) through PET is possible performing three different acquisition stages: rest, cold pressor test (CPT) and pharmacologic stress using Ammonia as radiotracer. The aim of this study was to evaluate the CBF, the CFR and the EDVI in healthy Mexican volunteers. RESULTS: Global basal CBF was 0.34 (+/- 0.09) mL/g/min, during CPT increased to 0.55 (+/- 0.17) mL/g/min and during the stress increased to 1.18 (+/- 0.25). CFR was 3.5 (+/- 0.65) and EDVI was 1.55 (+/- 0.33). CONCLUSIONS: CFR and EDVI values obtained in Mexican healthy population correlates very well with those reported in the literature. This values represents a reference to further research that use this technology.

Adolescent↗
PubMedDate not supplied

[Evaluation of coronary artery disease by myocardial perfusion imaging in women].

UNLABELLED: The early diagnosis of coronary artery disease continues to be a challenge in women because non invasive diagnostic tests to evaluate ischemia, such as stress test are less accurate in this group of patients. The aim of the study was to assess the value of myocardial perfusion imaging with SPECT for the detection of ischemia. METHODS: We studied 151 consecutive women who were assessed by SPECT with Tc-99m Sestamibi, stress test and coronary angiography. Sensitivity and specificity was calculated for each test. RESULTS: The prevalence of angiographycally significant coronary artery disease was 71.5%. The sensitivity and specificity of myocardial perfusion imaging for the detection of ischemia was 91.6% and 87.9% respectively. The sensitivity and specificity of stress test was 43% and 96.1%. Accuracy of myocardial perfusion imaging was higher in the group of patients older than 50 years of age, in whom severe coronary artery disease was more prevalent. CONCLUSIONS: The result of this study suggest that myocardial perfusion imaging is a very useful tool for detection of ischemia in women with CAD, especially for those over 50 years of age, being superior to other non invasive tests as stress test.

Coronary Artery Disease↗
PubMedDate not supplied

[Analysis of the ulsefulnes of contrast echocardiography and nuclear medicine in cardiovascular affection due to autoimmune diseases].

A significant correlation between autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and premature or accelerated coronary atherosclerosis was found. The objectives of the study were: a) evaluate myocardial perfusion in patients with rheumatic diseases by means of contrast echocardiography (CE) and to establish its usefulness as compared to the results obtained by nuclear medicine (NM) (reference method). b) evaluate the prevalence of alterations in subclinical myocardial perfusion in autoimmune diseases and to establish a strategy to evaluate the cardiovascular changes in this disease. Myocardial perfusion in 37 outpatients of the rheumatology department was evaluated by CE at rest and with pharmacological stress (dobutamine) and NM. The prevalence of alterations in the myocardial perfusion in autoimmune diseases by CE and NM, when these methods were analyzed independently or when both methods were used was 27%. The positive predictive value (PPV) and negative predictive value (NPV) of both tests was 80% and 93%, respectively, the sensitivity was 80% and the specificity was 93%. The prevalence of alterations of perfusion in the primary antiphospholipid syndrome (PAPS) was of 30%. In this patients it was found that when both diagnostic tests are performed, NM reaches a sensitivity of 100% if the CE is positive and an specificity of 100% when the CE is negative. We can conclude that it is important to determine the presence of subclinic coronary artery disease in patients with autoimmune disease by noninvasive studies such as Sestamibi SPECT and/or CE for assessment of myocardial perfusion in order to plan an adequate treatment and follow-up.

Adolescent↗
PubMedDate not supplied

[Study of myocardial viability: comparison of PET and MRI].

BACKGROUND: In the last years, few methods for the assessment of myocardial viability have been developed. Now a days the gold standard test for this purpose is the Positron Emission Tomography (PET). Recently, the expansion of Cardiovascular Magnetic Resonance imaging (MRI) has promoted the research for indexes or scores than can predict myocardial viability; so far, the late enhancement has proved to be one of the most accurate scores. The purpose of this study is to establish a correlation between the information of PET with the results of MRI in the assessment of myocardial viability. Late enhancement patterns and segmental mobility were compared. Sensitivity, specificity and positive and negative predictive values were calculated. SPSS v. 10 program was used for the statistic analysis. METHODS: 17 patients with diagnosis of myocardial infarction were enrolled. All of them underwent into a myocardial viability detection PET study and into a cardiovascular magnetic resonance study using a late enhancement technique. Results were interpreted by experts. The 17 segments model of The American Heart Association was used. RESULTS: A total of 289 myocardial segments were analyzed, by PET 239 (82%) viable segments and 50 (17.3%) of non viable segments were detected, meanwhile by MRI 210 (72.6%) and 79 (27.4%) of viable and non viable myocardial segments respectively were found. Both techniques correlate 75% of the times and when vascular territories were analyzed, a good correlation was also established. CONCLUSIONS: MRI is an adequate technique to determine viability since it has good correlation with PET. This is the first study realized in Latin America that compares PET and MRI in the diagnosis of myocardial viability.

Female↗
PubMedDate not supplied

[Inflammatory activity in Takayasu arteritis. Detection through positron emission tomography (PET)].

Takayasu arteritis (TA) is a chronic disease that affects mainly the aorta. Its etiology is still unknown, nevertheless it predominates in women and initiates primarily in the youth. This disease seems to have two different stages, an early stage that is characterized by an inflammatory process and a later stage characterized by vascular occlusion. Unitl now, diagnosis and classification of TA are made clinically, based on ACR; criteria and imaging studies as computed tomography and aorta angiographies. Currently, new imaging, non invasive studies, such as magnetic resonance (MRI) and positron emission tomography (PET) are being used. PET technique could be helpful in the diagnosis and detection of inflammatory activity in patients with TA because of its capacity to detect increased metabolism. We present the case of a female patient with TA diagnosis, which demonstrated clinical inflammatory activity that was corroborated by laboratory studies, MRI and PET.

Adult↗
PubMedDate not supplied

Comparison of 18FDG PET with thallium SPECT in the assessment of myocardial viability. A segmental model analysis.

BACKGROUND: In patients with myocardial infarction and left ventricular dysfunction, the evidence of myocardial viability is primordial. There are some methods to detect the presence of myocardial viability, 201 thallium reinjection SPECT protocol represents the most common radioisotopic technique to evaluate it. Positron emission tomography (PET) using FDG is considered the gold standard. The aim of this study was to compare globally and by segments the value of both techniques in the detection of viable myocardium. METHODS: Twenty-three consecutive patients with previous myocardial infarction and left ventricular dysfunction were studied. All of them underwent into a SPECT perfusion scan and a FDG PET study to asses myocardial viability. Each study was performed in less than one week between the other. For the analysis, the myocardium was divided into 17 segments. A visual semi-quantitative analysis was carried out according to the following score indicating radiotracer uptake: O = normal to 4 = absent. Myocardial viability was defined as the presence of normal, mildly or moderately reduced radiotracer uptake. The scores obtained by PET were compared to those obtained in SPECT. A statistical analysis was performed using the SPSS v. 10. RESULTS: 391 segments were analyzed. PET detected viability in 130 segments that had been defined as non-viable by SPECT. No differences in the analysis by vascular territories were found. Thirty percent of the segments that were defined as non viable by SPECT were viable by PET, meanwhile only 1% of the segments detected viable by SPECT were considered non viable with PET. CONCLUSIONS: FDG PET study represents a better technique to detect myocardial viability, compared to thallium reinjection SPECT protocol. By this study we have demonstrated that more of 3 of each 10 studies may be diagnosed as non viable where viability is present.

Female↗
PubMedDate not supplied

[Identification of acute myocardial infarction with PET and CT multislice].

Today non invasive cardiovascular imaging techniques exist, such as positron emission tomography (PET) and 16 multislice computed tomography (16-MSCT). With these studies, it is possible to evaluate the function and anatomy of the heart respectively. There is not enough information in the literature about the usefulness for 16-MSCT in the evaluation of infarcts. In this article, we show images of a patient who arrived to our institution and in whom it was possible to obtain important information with both imaging techniques. With the results, we obtained a good correlation of an infarct zone with PET and 16-MSCT. 16-MSCT is a good technique for observing infarcted zones of the heart. PET/CT is a non invasive cardiovascular imaging technique capable of giving enough anatomic and functional information.

Humans↗
PubMedDate not supplied

[Experience with the use of positron emission tomography (PET) in Mexico].

BACKGROUND: Positron Emission Tomography (PET) is a non-invasive imaging diagnostic tool that allows the study of specific biochemical processes using labeled molecules that closely mimic endogenous molecules. The two radiopharmaceuticals used in our facility are 13N-Ammonia and 18F-2-deoxy-2 fluor D-glucose (18F-FDG). 18F-FDG is the most common radiopharmaceutical used both at our Unit as well as worldwide, as it allows the study of tumor activity, the heart's metabolic activity, distinguish viable from non-viable myocardium and assess cerebral metabolism, among others. OBJECTIVES: Describe the experience in the use of PET scan in our country in the fields of oncology, cardiology and neuropsychiatry. METHODS: We performed an observational, retrospective, cross-sectional, and descriptive study. RESULTS: We analyzed a total of 1,154 studies performed at the UNAM-PET-Cyclotron Unit belonging to the Faculty of Medicine at the National Autonomous University of Mexico (UNAM). From the studies, 72.1% (832) corresponded to oncology, whereas 18.5% (213) and 9.4% (109) belonged to cardiology and neuropsychiatry, respectively. CONCLUSIONS: The studies performed at the UNAM-PET-Cyclotron Unit places it as the site with the largest PET experience in our country.

Adolescent↗