Assessment of late-term progression of cardiac allograft vasculopathy in patients with orthotopic heart transplantation using quantitative cardiac Rb PET.

The risk stratification and long-term survival of patients with orthotopic heart transplantation (OHT) is impacted by the complication of cardiac allograft vasculopathy (CAV). This study evaluates changes in myocardial blood flow (MBF) and myocardial coronary flow reserve (CFR) in a group of long-term OHT patients using quantitative cardiac Rb-positron emission tomography (PET). Twenty patients (7 females and 13 males, mean age = 72.

A combined static-dynamic single-dose imaging protocol to compare quantitative dynamic SPECT with static conventional SPECT.

Background: SPECT myocardial perfusion imaging (MPI) is a clinical mainstay that is typically performed with static imaging protocols and visually or semi-quantitatively assessed for perfusion defects based upon the relative intensity of myocardial regions. Dynamic cardiac SPECT presents a new imaging technique based on time-varying information of radiotracer distribution, which permits the evaluation of regional myocardial blood flow (MBF) and coronary flow reserve (CFR). In this work, a preliminary feasibility study was conducted in a small patient sample designed to implement a unique combined static-dynamic single-dose one-day visit imaging protocol to compare quantitative dynamic SPECT with static conventional SPECT for improving the diagnosis of coronary artery disease (CAD).

Noninvasive PET quantitative myocardial blood flow with regadenoson for assessing cardiac allograft vasculopathy in orthotopic heart transplantation patients.

Background: Risk stratification and early detection of cardiac allograft vasculopathy (CAV) is essential in orthotopic heart transplantation (OHT) patients. This study assesses the changes in myocardial blood flow (MBF) noninvasively in OHT patients using quantitative cardiac PET with regadenoson.

Methods: Twelve patients (Group 1) (8 males, 4 females, mean age 55 ± 7 years) with no history of post OHT myocardial ischemia were enrolled 5.

Utility of Equilibrium Radionuclide Angiogram-Derived Measures of Dyssynchrony to Predict Outcomes in Heart Failure Patients Undergoing Cardiac Resynchronization Therapy.

Unlabelled: We evaluated a novel scintigraphic method using new parameters of mechanical left ventricular (LV) dyssynchrony and correlated it with clinical outcomes in heart failure patients with reduced ejection fraction receiving cardiac resynchronization therapy (CRT).

Methods: Sixty-six advanced heart failure patients referred for CRT with an LV ejection fraction (EF) of < 35% and QRS ≥ 120 ms were studied. We performed equilibrium radionuclide angiography (ERNA) before and 6 mo after CRT.

Measurement of absolute myocardial blood flow in humans using dynamic cardiac SPECT and Tc-tetrofosmin: Method and validation.

Background: The objective of this study was to measure myocardial blood flow (MBF) in humans using Tc-tetrofosmin and dynamic single-photon emission computed tomography (SPECT).

Methods: Dynamic SPECT using Tc-tetrofosmin and dynamic positron emission tomography (PET) was performed on a group of 16 patients. The SPECT data were reconstructed using a 4D-spatiotemporal iterative reconstruction method.

Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration.

Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart.

Comparison of radionuclide angiographic synchrony analysis to echocardiography and magnetic resonance imaging for the diagnosis of arrhythmogenic right ventricular cardiomyopathy.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable arrhythmia syndrome entailing a high risk of sudden cardiac death. Discernment from benign arrhythmia disorders, particularly right ventricular outflow tract ventricular tachycardia (RVOT VT), may be challenging, providing an impetus to explore alternative modalities that may facilitate evaluation of patients with suspected ARVC.

Objective: We evaluated the role of equilibrium radionuclide angiography (ERNA) as a diagnostic tool for ARVC.

Quantitative Signature of in a Patient with Occluded Coronary Arteries Supported by Collateral Circulation Using Dynamic SPECT.

(CS) is a physiological process that induces absolute decrease in blood flow in collateralized myocardium compared to resting flow during coronary vasodilation due to redistribution of blood away from collateral-dependent myocardium. Although, CS has been well known for decades, there are very few noninvasive perfusion studies in humans that quantitatively predict the existence of CS. In this study, we show that the quantitative measurement of absolute value of regional myocardial blood flow (MBF) and coronary flow reserve (CFR) using dynamic single photon emitted computed tomography (SPECT) can help estimate the presence of CS in myocardium with obstructed coronary artery and collateral circulation.

Current methods of pharmacologic stress testing and the potential advantages of new agents.

This article presents the exciting advances made and ongoing in the area of pharmacologic cardiac stress testing. In particular, new A(2A)-specific receptor agonists work like adenosine but promise the delivery of uncomplicated vasodilator stress testing or the diagnosis and prognosis of coronary disease. These agents, although not perfect, do likely present a level of protection against the complications of bronchospasm and heart block.

Age-related decrease in cardiopulmonary adrenergic neuronal function in children as assessed by I-123 metaiodobenzylguanidine imaging.

Background: Radioiodinated metaiodobenzylguanidine (MIBG) imaging has been used to evaluate adrenergic nerve activity in different organs. Cardiac and pulmonary MIBG uptake is important in predicting the prognosis of certain cardiopulmonary diseases. It has been reported that cardiac MIBG uptake decreases with age and is significantly lower in the elderly.

A unique method by which to quantitate synchrony with equilibrium radionuclide angiography.

Background: Cardiac resynchronization therapy (CRT) improves symptoms and the survival rate in patients with advanced heart failure by improving synchrony. However, CRT is not always successful, is costly, and is applied without individualization. There is no specific measure of synchrony.

Unique contraction pattern in patients after coronary bypass graft surgery by gated SPECT myocardial perfusion imaging.

Purpose: Although left ventricular systolic function seems to be accurately represented on gated SPECT myocardial perfusion imaging, specific patterns of wall motion (WM) and thickening after coronary bypass graft surgery (CABG), demonstrated by other imaging methods, have not been characterized for gated SPECT myocardial perfusion imaging.

Methods: Gated SPECT myocardial perfusion imaging was studied in 30 consecutive patients after CABG (group 1) and 40 non-CABG patients-30 with normal stress perfusion studies (group 2) and 10 with known previous anterior wall infarction (group 3). Two expert readers evaluated epicardial and endocardial systolic WM.