Clinical performance of Rb-82 myocardial perfusion PET and Tc-99m-based SPECT in patients with extreme obesity.

Background: We evaluated the performance of stress imaging with technetium-99m-labeled tetrofosmin single-photon emission computed tomography (SPECT) and rubidium-82 positron emission tomography (PET) in patients with extreme obesity, defined as body mass index ≥40 kg/m.

Methods: We identified patients with extreme obesity who underwent angiography in our center and either stress SPECT or PET within the previous six months. Cohorts of patients with extreme obesity and a <5% pretest likelihood of CAD who underwent SPECT (N = 25) or PET (N = 25) were also included.

Myocardial viability: it is still alive.

Heart failure presents a significant problem in industrialized countries, with a high prevalence, morbidity, and mortality, where it is most frequently caused by coronary artery disease. Revascularization in patients with symptomatic heart failure has been associated with improved cardiovascular outcomes. Predictors of outcome benefit from revascularization include the presence and extent of hibernating myocardium, ischemia, scar, left ventricular ejection fraction, and renal function.

Prognostic value of rubidium-82 positron emission tomography in patients after heart transplant.

Background: Cardiac allograft vasculopathy is a key prognostic determinant after heart transplant. Detection and risk stratification of patients with cardiac allograft vasculopathy are problematic. Positron emission tomography using rubidium-82 allows quantification of absolute myocardial blood flow and may have utility for risk stratification in this population.

Atrioventricular block as the initial manifestation of cardiac sarcoidosis in middle-aged adults.

Introduction: Atrioventricular block (AVB) can be caused by several conditions, including cardiac sarcoidosis (CS). The prevalence of CS causing this presentation in a North American population has not been investigated and was the purpose of this study.

Methods: We prospectively evaluated patients aged 18-60 years presenting with unexplained 2nd or 3rd degree AVB and no previous history of sarcoidosis in any organ.

Prevalence of cardiac sarcoidosis in patients presenting with monomorphic ventricular tachycardia.

Introduction: Sarcoidosis is a granulomatous disease of unknown etiology, which involves the heart in 5-25% of cases. Although ventricular tachycardia (VT) has been reported as the first presentation of sarcoidosis, its prevalence has not previously been investigated. In this prospective study, we sought to systematically investigate the prevalence of cardiac sarcoidosis (CS) in patients presenting with monomorphic VT (MMVT) and no previous history of sarcoidosis.

Is there an association between clinical presentation and the location and extent of myocardial involvement of cardiac sarcoidosis as assessed by ¹⁸F- fluorodoexyglucose positron emission tomography?

Background: Positron emission tomography using (18)F-Fluorodeoxyglucose (FDG) is an emerging modality for diagnosis of cardiac sarcoidosis (CS). We compared the location and degree of FDG uptake in CS patients presenting with either advanced atrioventricular block (AVB) or ventricular tachycardia (VT).

Methods And Results: We included consecutive patients who presented with either AVB or VT with a diagnosis of CS.

Myocardial viability: whom, what, why, which, and how?

Viability imaging might be useful to guide decisions for revascularization in patients with ischemic cardiomyopathy. Recent trial results raise important points for clinicians regarding which modalities to use and in which patients. We discuss the modalities currently used in clinical practice.

Does rubidium-82 PET have superior accuracy to SPECT perfusion imaging for the diagnosis of obstructive coronary disease?: A systematic review and meta-analysis.

Objectives: The purpose of this study was to evaluate the accuracy of rubidium (Rb)-82 positron emission tomography (PET) for the diagnosis of obstructive coronary artery disease (CAD) in comparison to single-photon emission tomography (SPECT).

Background: Myocardial perfusion imaging is widely used in the assessment of patients with known or suspected CAD. PET using Rb-82 has potential advantages over SPECT that may make it more accurate and that reduce radiation exposure compared with SPECT but has increased costs.

Sampling state and process variables on coral reefs.

Contemporary coral reefs are forced to survive through and recover from disturbances at a variety of spatial and temporal scales. Understanding disturbances in the context of ecological processes may lead to accurate predictive models of population trajectories. Most coral-reef studies and monitoring programs examine state variables, which include the percentage coverage of major benthic organisms, but few studies examine the key ecological processes that drive the state variables.