Automated Deep Learning Segmentation of Cardiac Inflammatory FDG PET.

Background: Fluorodeoxyglucose positron emission tomography (FDG PET) with glycolytic metabolism suppression plays a pivotal role in diagnosing cardiac sarcoidosis. Reorientation of images to match perfusion datasets is critical and myocardial segmentation enables consistent image scaling and quantification. However, both are challenging and labor intensive.

Self-supervised deep representation learning of a foundation transformer model enabling efficient ECG-based assessment of cardiac and coronary function with limited labels.

Although deep learning methods have shown great promise for identification of structural and functional cardiac abnormalities using electrocardiographic data, these methods are data hungry, posing a challenge for critically important tasks where ground truth labels are relatively scarce. Impaired coronary microvascular and vasomotor function is difficult to identify with standard clinical methods of cardiovascular testing such as coronary angiography and noninvasive single photon emission tomography (SPECT) myocardial perfusion imaging (MPI). Gold standard data from positron emission tomography (PET) are gaining emphasis in clinical guidelines but are expensive and only available in relatively limited centers.

Integrated myocardial flow reserve (iMFR) assessment: diffuse atherosclerosis and microvascular dysfunction are more strongly associated with mortality than focally impaired perfusion.

Background And Aims: Although treatment of ischemia-causing epicardial stenoses may improve symptoms of ischemia, current evidence does not suggest that revascularization improves survival. Conventional myocardial ischemia imaging does not uniquely identify diffuse atherosclerosis, microvascular dysfunction, or nonobstructive epicardial stenoses. We sought to evaluate the prognostic value of integrated myocardial flow reserve (iMFR), a novel noninvasive approach to distinguish the perfusion impact of focal atherosclerosis from diffuse coronary disease.

Changes in myocardial blood flow in a canine model of left sided breast cancer radiotherapy.

Background: Left-sided breast cancer patients receiving adjuvant radiotherapy are at risk for coronary artery disease, and/or radiation mediated effects on the microvasculature. Previously our laboratory demonstrated in canines with hybrid 18FDG/PET a progressive global inflammatory response during the initial one year following treatment. In this study, the objective is to evaluate corresponding changes in perfusion, in the same cohort, where resting myocardial blood flow (MBF) was quantitatively measured.

Improved diagnostic accuracy for coronary artery disease detection with quantitative 3D Rb PET myocardial perfusion imaging.

Purpose: To establish requirements for normal databases for quantitative rubidium-82 (Rb) PET MPI analysis with contemporary 3D PET/CT technology and reconstruction methods for maximizing diagnostic accuracy of total perfusion deficit (TPD), a combined metric of defect extent and severity, versus invasive coronary angiography.

Methods: In total, 1571 patients with Rb PET/CT MPI on a 3D scanner and stress static images reconstructed with and without time-of-flight (TOF) modeling were identified. An additional eighty low pre-test probability of disease (PTP) patients reported as normal were used to form separate sex-stratified and sex-independent iterative and TOF normal databases.

Evaluation of Lung Glucose Uptake with Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/CT in Patients with Pulmonary Arterial Hypertension and Pulmonary Hypertension Due to Left Heart Disease.

: Previous studies have demonstrated increased glucose uptake by F-fluorodeoxyglucose positron emission tomography (FDG-PET) in lung parenchyma in animal models or small pulmonary arterial hypertension (PAH) cohorts. However, it is not well known whether increased FDG uptake in the lung is a unique phenomenon in PAH or whether elevated pulmonary artery pressure (PAP) induces FDG uptake. : Nineteen patients with PAH, 8 patients with pulmonary hypertension due to left heart disease (PH-LHD), and 14 age matched control subjects were included.

"Virtual" attenuation correction: improving stress myocardial perfusion SPECT imaging using deep learning.

Purpose: Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) is widely used for coronary artery disease (CAD) evaluation. Although attenuation correction is recommended to diminish image artifacts and improve diagnostic accuracy, approximately 3/4ths of clinical MPI worldwide remains non-attenuation-corrected (NAC). In this work, we propose a novel deep learning (DL) algorithm to provide "virtual" DL attenuation-corrected (DLAC) perfusion polar maps solely from NAC data without concurrent computed tomography (CT) imaging or additional scans.

Effect of iterations and time of flight on normal distributions of Rb PET relative perfusion and myocardial blood flow.

Background: As clinical use of myocardial blood flow (MBF) increases, dynamic series are becoming part of the typical workflow. The methods and parameters used to reconstruct these series require investigation to ensure accurate quantification.

Methods: Fifty-nine rest/stress dynamic Rb PET studies, acquired on a Biograph mCT, from a combination of normal volunteers and low-likelihood patients were reconstructed with and without time of flight (TOF) for varying iterations and processed to obtain relative perfusion and MBF polar maps.

Myocardial flow reserve estimation with contemporary CZT-SPECT and Tc-tracers lacks precision for routine clinical application.

Background: PET myocardial flow reserve (MFR) has established diagnostic and prognostic value. Technological advances have now enabled SPECT MFR quantification. We investigated whether SPECT MFR precision is sufficient for clinical categorization of patients.

Does quantification of [C]meta-hydroxyephedrine and [N]ammonia kinetics improve risk stratification in ischemic cardiomyopathy.

Background: In ischemic cardiomyopathy patients, cardiac sympathetic nervous system dysfunction is a predictor of sudden cardiac arrest (SCA). This study compared abnormal innervation and perfusion measured by [C]meta-hydroxyephedrine (HED) vs [N]ammonia (NH), conventional uptake vs parametric tracer analysis, and their SCA risk discrimination.

Methods: This is a sub-study analysis of the prospective PAREPET trial, which followed ischemic cardiomyopathy patients with reduced left ventricular ejection fraction (LVEF ≤ 35%) for events of SCA.

Effects of two patient-specific dosing protocols on measurement of myocardial blood flow with 3D Rb cardiac PET.

Purpose: Clinical measurement of myocardial blood flow (MBF) has emerged as an important component of routine PET-CT assessment of myocardial perfusion in patients with known or suspected coronary artery disease. Although multiple society guidelines recommend patient-specific dosing, there is a lack of studies evaluating the efficacy of patient-specific dosing for quantitative MBF accuracy.

Methods: Two patient-specific dosing protocols (weight- and BMI-adjusted) were retrospectively evaluated in 435 consecutive clinical patients referred for PET myocardial perfusion assessment.

Internal validation of myocardial flow reserve PET imaging using stress/rest myocardial activity ratios with Rb-82 and N-13-ammonia.

Background: Myocardial flow reserve (MFR) measurement provides incremental diagnostic and prognostic information. The objective of the current study was to investigate the application of a simplified model for the estimation of MFR using only the stress/rest myocardial activity ratio (MAR) in patients undergoing rest-stress cardiac PET MPI.

Methods And Results: Rest and dipyridamole stress dynamic PET imaging was performed in consecutive patients using Rb or NH (n = 250 each).

Quantitative clinical nuclear cardiology, part 2: Evolving/emerging applications.

Quantitative analysis has been applied extensively to image processing and interpretation in nuclear cardiology to improve disease diagnosis and risk stratification. This is Part 2 of a two-part continuing medical education article, which will review the potential clinical role for emerging quantitative analysis tools. The article will describe advanced methods for quantifying dyssynchrony, ventricular function and perfusion, and hybrid imaging analysis.

Quantitative clinical nuclear cardiology, part 2: Evolving/emerging applications.

Quantitative analysis has been applied extensively to image processing and interpretation in nuclear cardiology to improve disease diagnosis and risk stratification. This is Part 2 of a two-part continuing medical education article, which will review the potential clinical role for emerging quantitative analysis tools. The article will describe advanced methods for quantifying dyssynchrony, ventricular function and perfusion, and hybrid imaging analysis.

Adjuvant FOLFOX+Nab-Paclitaxel (FOLFOX-A) for Pancreatic Cancer: A Brown University Oncology Research Group Phase II Study (BrUOG295).

Objectives: Multiple clinical trials have established a role for adjuvant chemotherapy for patients with pancreatic ductal adenocarcinoma. Adjuvant FOLFIRINOX increases survival as compared with gemcitabine but with increased toxicity. FOLFOX+nab-paclitaxel (FOLFOX-A) was developed by the Brown University Oncology Research Group (BrUOG) as an alternative to FOLFIRINOX.

Increased myocardial oxygen consumption rates are associated with maladaptive right ventricular remodeling and decreased event-free survival in heart failure patients.

Background: Reduced left ventricular (LV) function is associated with increased myocardial oxygen consumption rate (MVO) and altered sympathetic activity, the role of which is not well described in right ventricular (RV) dysfunction.

Methods And Results: 33 patients with left heart failure were assessed for RV function/size using echocardiography. Positron emission tomography (PET) was used to measure C-acetate clearance rate (k), C-hydroxyephedrine (C-HED) standardized uptake value (SUV), and retention rate.