Reducing motion-correction-induced variability in rubidium myocardial blood-flow quantification.

Background: Clinical use of myocardial blood flow (MBF) and flow reserve (MFR) is increasing. Motion correction is necessary to obtain accurate results but can introduce variability when performed manually. We sought to reduce that variability with an automated motion-correction algorithm.

Initial clinical experience of N13-ammonia myocardial perfusion PET/CT using a compact superconducting production system.

Background: Although N13-ammonia has favorable properties among FDA approved radiotracers, complexity of implementation has limited its use. We describe the initial patient experience of N13-ammonia PET imaging using a compact N13-ammonia production system.

Methods: N13 was produced using the ION-12SC, a 12MeV, 10uA superconducting minimally shielded cyclotron, and reduced to N13-ammonia in an automated multi-use purification unit.

Diagnostic Accuracy of FDG PET/CT in Suspected LVAD Infections: A Case Series, Systematic Review, and Meta-Analysis.

Objectives: The purpose of this study was to describe our experience with fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT) in diagnosing left ventricular assist device (LVAD) infections and perform a meta-analysis of published studies to determine overall diagnostic accuracy.

Background: Device-related infections are a common complication of LVADs and are linked to worse outcomes. Diagnosis of LVAD infections remains challenging.

Characterization of a highly effective preparation for suppression of myocardial glucose utilization.

Background: With appropriate protocols, F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can visualize myocardial inflammation. Optimal protocols and normative myocardial FDG uptake values are not well-established.

Methods: We evaluated 111 patients referred for inflammation cardiac FDG PET/CT.

The utility of Rb PET for myocardial viability assessment: Comparison with perfusion-metabolism Rb-F-FDG PET.

Background: Rb kinetics may distinguish scar from viable but dysfunctional (hibernating) myocardium. We sought to define the relationship between Rb kinetics and myocardial viability compared with conventional Rb and F-fluorodeoxyglucose (FDG) perfusion-metabolism PET imaging.

Methods: Consecutive patients (N = 120) referred for evaluation of myocardial viability prior to revascularization and normal volunteers (N = 37) were reviewed.

Safety of regadenoson positron emission tomography stress testing in orthotopic heart transplant patients.

Objectives: We sought to determine the safety of regadenoson (REG) stress testing in patients who have undergone orthotopic heart transplantation (OHT).

Background: Routine screening for cardiac allograft vasculopathy (CAV) is necessary after OHT. Adenosine stress is contraindicated after heart transplantation due to supersensitivity in denervated hearts.

Automated dynamic motion correction using normalized gradient fields for rubidium PET myocardial blood flow quantification.

Background: Patient motion can lead to misalignment of left ventricular (LV) volumes-of-interest (VOIs) and subsequently inaccurate quantification of myocardial blood flow (MBF) and flow reserve (MFR) from dynamic PET myocardial perfusion images. We aimed to develop an image-based 3D-automated motion-correction algorithm that corrects the full dynamic sequence for translational motion, especially in the early blood phase frames (~ first minute) where the injected tracer activity is transitioning from the blood pool to the myocardium and where conventional image registration algorithms have had limited success.

Methods: We studied 225 consecutive patients who underwent dynamic rest/stress rubidium-82 chloride (Rb) PET imaging.

Multiparametric assessment of left atrial remodeling using F-FDG PET/CT cardiac imaging: A pilot study.

Background: Left atrial (LA) remodeling is associated with structural, electric, and metabolic LA changes. Integrated evaluation of these features in vivo is lacking.

Methods: Patients undergoing F-fluorodeoxyglucose (FDG) PET-CT during a hyperinsulinemic-euglycemic clamp were classified into sinus rhythm (SR), paroxysmal AF (PAF), and persistent AF (PerAF).

Reduced Myocardial Flow Reserve by Positron Emission Tomography Predicts Cardiovascular Events After Cardiac Transplantation.

Background: We evaluated the diagnostic and prognostic value of quantification of myocardial flow reserve (MFR) with positron emission tomography (PET) in orthotopic heart transplant patients.

Methods And Results: We retrospectively identified orthotopic heart transplant patients who underwent rubidium-82 cardiac PET imaging. The primary outcome was the composite of cardiovascular death, acute coronary syndrome, coronary revascularization, and heart failure hospitalization.

Reduced Myocardial Flow Reserve Is Associated With Diastolic Dysfunction and Decreased Left Atrial Strain in Patients With Normal Ejection Fraction and Epicardial Perfusion.

Introduction: Coronary microvascular dysfunction (MVD) may contribute to the pathogenesis of heart failure with preserved ejection fraction (HFpEF). Using myocardial flow reserve (MFR) measured by positron emission tomography (PET) as an assessment of microvascular function, we hypothesized that abnormal MFR is associated with LV diastolic dysfunction (DD) and reduced LV and LA strain in patients with risk factors for HFpEF and normal epicardial perfusion on cardiac PET.

Methods And Results: Retrospective study of patients without heart failure who underwent cardiac rubidium-82 PET and echocardiography.

Relationship of non-invasive quantification of myocardial blood flow to arrhythmic events in patients with implantable cardiac defibrillators.

Background: Ischemia contributes to arrhythmogenesis though its role is incompletely understood. Abnormal myocardial perfusion measured by PET imaging may predict ventricular arrhythmias (VAs) in a high-risk population.

Methods: Patients with implantable cardiac defibrillators who had undergone rubidium-82 cardiac PET imaging were identified.

Optimization of temporal sampling for rubidium PET myocardial blood flow quantification.

Background: Suboptimal temporal sampling of left ventricular (LV) blood pool and tissue time-activity curves (TACs) may introduce bias and increased variability in estimates of myocardial blood flow (MBF) and flow reserve (MFR) from dynamic PET myocardial perfusion images. We aimed to optimize temporal sampling for estimation of MBF and MFR.

Methods: Twenty-four normal volunteers and 32 patients underwent dynamic stress/rest rubidium-82 chloride (Rb) PET imaging.

Safety of regadenoson stress testing in patients with pulmonary hypertension.

Objectives: We sought to determine the safety of regadenoson stress testing in patients with PH.

Background: PH is increasingly recognized at more advanced ages. As many as one-third of patients with PH have coronary artery disease.

Limitations of Rb-82 weight-adjusted dosing accuracy at low doses.

Introduction: Weight-adjusted dosing is important to maintain accurate quantification for dynamic cardiac three-dimensional positron emission tomography (PET). However, the manufacturer of the only Food and Drug Administration approved rubidium-82 (Rb-82) generator (CardioGen-82, Bracco Diagnostics, Inc.) recommends recalibration after each change in dose which is inefficient in a busy clinical PET lab.

Variance Estimation for Myocardial Blood Flow by Dynamic PET.

The estimation of myocardial blood flow (MBF) by (13)N-ammonia or (82)Rb dynamic PET typically relies on an empirically determined generalized Renkin-Crone equation to relate the kinetic parameter K1 to MBF. Because the Renkin-Crone equation defines MBF as an implicit function of K1, the MBF variance cannot be determined using standard error propagation techniques. To overcome this limitation, we derived novel analytical approximations that provide first- and second-order estimates of MBF variance in terms of the mean and variance of K1 and the Renkin-Crone parameters.

Precision and accuracy of clinical quantification of myocardial blood flow by dynamic PET: A technical perspective.

A number of exciting advances in PET/CT technology and improvements in methodology have recently converged to enhance the feasibility of routine clinical quantification of myocardial blood flow and flow reserve. Recent promising clinical results are pointing toward an important role for myocardial blood flow in the care of patients. Absolute blood flow quantification can be a powerful clinical tool, but its utility will depend on maintaining precision and accuracy in the face of numerous potential sources of methodological errors.

Metastatic renal cell carcinoma avid for 82Rb but not 18F-FDG.

Renal cell carcinoma has a variable uptake of F-FDG resulting in poor sensitivity and limited clinical application. There is intense interest in improved molecular imaging of this condition. We present a case of a 64-year-old man with known metastatic renal cell carcinoma found to have intense uptake of Rb but not F-FDG in multiple thoracic metastases seen on imaging performed to assess myocardial hibernation.

Is there a dose-response relationship for heart disease with low-dose radiation therapy?

Purpose: To quantify cardiac radiation therapy (RT) exposure using sensitive measures of cardiac dysfunction; and to correlate dysfunction with heart doses, in the setting of adjuvant RT for left-sided breast cancer.

Methods And Materials: On a randomized trial, 32 women with node-positive left-sided breast cancer underwent pre-RT stress single photon emission computed tomography (SPECT-CT) myocardial perfusion scans. Patients received RT to the breast/chest wall and regional lymph nodes to doses of 50 to 52.

Interpretation of SPECT/CT myocardial perfusion images: common artifacts and quality control techniques.

Nuclear medicine has long played an important role in the noninvasive evaluation of known or suspected coronary artery disease. The development of single photon emission computed tomography (SPECT) led to improved assessments of myocardial perfusion, and the use of electrocardiographic gating made accurate measurements of ventricular wall motion, ejection fractions, and ventricular volumes possible. With the use of hybrid SPECT/computed tomography (CT) scanning systems, the cardiac functional parameters can be measured in a single imaging session.

Fragmented QRS complex has poor sensitivity in detecting myocardial scar.

Objective: To study the association of the fragmented QRS complex versus the Q wave with myocardial scar and viability.

Background: A prior study has suggested that the fragmented QRS complex on an electrocardiogram (ECG) is a highly sensitive and specific marker of myocardial scar as detected by regional perfusion abnormalities on a nuclear stress test. There is no external validation of this data.