The novel PET flow tracer flurpiridaz F 18 shows high myocardial extraction and slow washout. flurpiridaz F 18 PET data analysis with tracer kinetic modeling provides accurate absolute myocardial blood flow (MBF) measurements but requires in-scanner injection and complex processing. We evaluated the hypothesis that myocardial retention and standardized uptake values (SUVs) based on late uptake provide accurate estimates of myocardial flow reserve (MFR) and, thus, might allow simplified quantification after tracer injection outside the scanner. Methods: Nine pigs had dynamic PET scans after repeated injections of flurpiridaz F 18 at rest and combined adenosine and dobutamine stress. flurpiridaz F 18 PET with a 3-compartment model and coinjected radioactive microspheres were used to delineate MBF. These quantitative measurements were compared with myocardial retention (%/min) and SUV of flurpiridaz F 18 after summing data over 5-10, 5-12, 5-15, 10-15, and 10-20 min after tracer injection. Results: MBF ranged from 0.5 to 2.8 mL/min/g. There was a good correlation between both flurpiridaz F 18 retention and SUVs from 5 to 12 min after injection and MBF measured using 3-compartment modelor microsphere-derived MBF (r 5 0.73, P , 0.05, and r 5 0.68, P , 0.05, respectively, for retention; r 5 0.88, P , 0.001, and r 5 0.92, P , 0.001, respectively, for SUV). At later time points, retention and SUV underestimated stress microsphere flow (at 10-20 min: r 5 0.41, P 5 not significant, and r 5 0.46, P 5 not significant, respectively, for retention; r 5 0.41, P 5 not significant, and r 5 0.65, P , 0.05, respectively, for SUV). When measured 5-12 min after injection, there was a close agreement between MFR measured with either flurpiridaz F 18 retention or SUV and MFR measured using microspheres (mean difference, 20.08 6 0.36 and 20.18 6 0.25, respectively). Conclusion: Myocardial retention and SUVs of the 18 F-labeled flow tracer flurpiridaz F 18 accurately reflect the MFR. These simplified analysis methods may facilitate the combination of quantitative assessment of perfusion reserve and rapid clinical imaging protocols. Myocardi al perfusion imaging with SPECT and PET is a standard tool for detection of coronary artery disease, risk stratification of patients, and guidance of therapeutic interventions (1-4). Usually, myocardial perfusion is analyzed in a qualitative manner, so that only relative perfusion changes can be detected. Absolute quantification of myocardial blood flow (MBF) and the subsequent calculation of myocardial flow reserve (MFR; the ratio of MBF at stress and rest) are a goal of essentially all invasive and noninvasive imaging approaches (4-8). Compared with qualitative analysis, quantitative assessment of perfusion can improve the accuracy with which coronary artery disease is detected. It can reduce the number of false-negative results in patients with multivessel disease, for which qualitative analysis often cannot uncover globally reduced perfusion or uncovers only the coronary territory supplied by the...

18 F-galacto-RGD ( 18 F-RGD) is a PET tracer binding to a v b 3 integrin receptors that are upregulated after myocardial infarction (MI) as part of the healing process. We studied whether myocardial 18 F-RGD uptake early after MI is associated with long-term left-ventricle (LV) remodeling in a rat model. Methods: Wistar rats underwent sham operation (n 5 9) or permanent coronary ligation (n 5 25). One week after MI, rats were injected with 18 F-RGD to evaluate a v b 3 integrin expression using a preclinical PET system. In the same rats, LV volumes and defect size were measured 1 and 12 wk after MI by 13 N-ammonia PET and MRI, respectively. Results: One week after MI, 18 F-RGD uptake was increased in the defect area as compared with the remote myocardium of MI rats or sham-operated controls (percentage injected dose per cubic centimeter, 0.20 6 0.05 vs. 0.06 6 0.03 and 0.07 6 0.04, P , 0.001). At this time, 18 F-RGD uptake was associated with capillary density in histologic sections. Average 18 F-RGD uptake in the defect area was lowest in the rats demonstrating greater than 20% relative increase in the LV end-diastolic volume from 1 to 12 wk (percentage injected dose per centimeter cubed, 0.15 6 0.07 vs. 0.21 6 0.05, P , 0.05). In a multivariable logistic regression analysis, low 18 F-RGD uptake was a significant predictor of increase in end-diastolic volume (r 5 0.51, P , 0.05). Conclusion: High levels of 18 F-RGD uptake in the perfusion defect area early after MI were associated with the absence of significant LV remodeling after 12 wk of follow-up. These results suggest that a v b 3 integrin expression is a potential biomarker of myocardial repair processes after MI and enables the monitoring of these processes by molecular imaging to derive possible prognostic information.

Objective: Despite previous research that focused on liver transaminases as predictors of cardiovascular disease, there has been limited research evaluating the predictive value of AST/ALT ratio in patients with heart failure. We aimed to investigate AST/ALT ratio as an indicator of the functional severity in chronic heart failure with reduced left ventricular ejection fraction. Results:Overall, 105 patients previously diagnosed with HFrEF from Buraidah-Al Qassim province, Saudi Arabia were included in this retrospective cross-sectional study. Data on study variables, including demographic data, left ventricular ejection fraction, NYHA class, and AST/ALT ratio, were collected from patients' records. The patients were divided into two groups, namely group-1 (AST/ALT ratio < 1) and group-2 (AST/ALT ratio ≥ 1), to identify any differences in their cardiac function profiles. NYHA class and NT-proBNP were higher and LVEF was lower in group-2 than in group-1. We found a mild significant correlation between AST/ALT ratio and APRI, FIB-4 score, NYHA-class, and LVEF (r = 0.2, 0.25, 0.26, and − 0.24, respectively; P < 0.05). Multivariate linear regression analysis model and ROC curve showed that AST/ALT ratio could independently predict HFrEF functional severity with a best cut-off value of 0.9, sensitivity of 43.6%, and specificity of 81.4%.

Myocardial (18)F BMS747158-02 PET imaging provides excellent image quality and uptake properties, enabling accurate evaluation of MI size and left ventricular function in rats. It is a promising technique for evaluation of MI size in clinical trials.