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Background: New Block-Sequential-Regularized-Expectation-Maximization (BSREM) image reconstruction technique has been introduced for clinical use mainly for oncologic use. Accurate and quantitative image reconstruction is essential in myocardial perfusion imaging with positron emission tomography (PET) as it utilizes absolute quantitation of myocardial blood flow (MBF). The aim of the study was to evaluate BSREM reconstruction for quantitation in patients with suspected coronary artery disease (CAD). Methods and Results: We analyzed cardiac [15O]H2O PET studies of 177 patients evaluated for CAD. Differences between BSREM and Ordered-Subset-Expectation-Maximization with Time-Of-Flight (TOF) and Point-Spread-Function (PSF) modeling (OSEM-TOF-PSF) in terms of MBF, perfusable tissue fraction, and vascular volume fraction were measured. Classification of ischemia was assessed between the algorithms. OSEM-TOF-PSF and BSREM provided similar global stress MBF in patients with ischemia (1.84 ± 0.21 g⋅ml−1⋅min−1 vs 1.86 ± 0.21 g⋅ml−1⋅min−1) and no ischemia (3.26 ± 0.34 g⋅ml−1⋅min−1 vs 3.28 ± 0.34 g⋅ml−1⋅min−1). Global resting MBF was also similar (0.97 ± 0.12 g⋅ml−1⋅min−1 and 1.12 ± 0.06 g⋅ml−1⋅min−1). The largest mean relative difference in MBF values was 7%. Presence of myocardial ischemia was classified concordantly in 99% of patients using OSEM-TOF-PSF and BSREM reconstructions Conclusion: OSEM-TOF-PSF and BSREM image reconstructions produce similar MBF values and diagnosis of myocardial ischemia in patients undergoing [15O]H2O PET due to suspected obstructive coronary artery disease [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to evaluate subjects with high-risk alcohol cardiotoxicity and patients with alcoholic cardiomyopathy (ACM) via dynamic 11C-Acetate positron emission tomography (PET) imaging as a myocardial oxidative metabolic probe. Methods and Results: We recruited 37 subjects with chronic alcohol consumption [18 with moderate consumption (MC), 19 with heavy consumption (HC)], 5 ACM patients, and 12 healthy controls to receive dynamic 11C-Acetate PET scans. PET imaging data were analyzed to calculate kinetic parameters (e.g., Kmono, K1 and k2) based on the mono-exponential and one-tissue compartmental models. Myocardial oxygen consumption (MVO2) and myocardial external efficiency (MEE) were then derived from these kinetic parameters. MVO2 was significantly lowered in the HC group and in ACM patients (0.121± 0.018 and 0.111 ± 0.017 mL·g−1·min−1, respectively) compared with those in healthy controls and MC subjects (0.144 ± 0.023 and 0.146 ± 0.027 mL·g−1·min−1, respectively; P <.01). MEE was significantly reduced in ACM patients (13.0% ± 4.3%) compared with those of healthy controls (22.4% ± 4.6%, P <.01), MC subjects (20.1% ± 4.5%, P <.05), and HC subjects (22.3% ± 4.5%, P <.001). Conclusion: Functional assessment via dynamic 11C-Acetate PET imaging may represent a clinically feasible probe for identifying cohorts with high-risk cardiotoxicity due to addictive alcohol consumption and ACM. [ABSTRACT FROM AUTHOR]

Background: We explored agreement in the quantification of myocardial perfusion by cross-comparison of implemented software packages (SPs) in three distinguishable patient profile populations.Methods: We studied 91 scans of patients divided into 3 subgroups based on their semi-quantitative perfusion findings: patients with normal perfusion, with reversible perfusion defects, and with fixed perfusion defects. Rest myocardial blood flow (MBF), stress MBF, and myocardial flow reserve (MFR) were obtained with QPET, SyngoMBF, and Carimas. Agreement between SPs was considered adequate when a pairwise standardized difference was found to be < 0.20 and its corresponding intraclass correlation coefficient was ≥ 0.75.Results: In patients with normal perfusion, two out of three comparisons of global stress MBF quantifications were outside the limits of agreement. In ischemic patients, all comparisons of global stress MBF and MFR were outside the limits of established agreement. In patients with fixed perfusion defects, all SP comparisons of perfusion quantifications were within the limit of agreement. Regionally, agreement of these perfusion estimates was mostly found for the left anterior descending artery vascular territory.Conclusion: Reversible defects demonstrated the worst agreement in global stress MBF and MFR and discrepancies showed to be regional dependent. Reproducibility between SPs should not be assumed. [ABSTRACT FROM AUTHOR]

Aims: Simultaneous measurement of right (RV) and left ventricle (LV) myocardial blood flow (MBF), oxygen extraction fraction (OEF), and oxygen consumption (MVO2) non-invasively in humans would provide new possibilities to understand cardiac physiology and different patho-physiological states. Methods: We developed and tested an optimized novel method to measure MBF, OEF, and MVO2 simultaneously both in the RV and LV free wall (FW) using positron emission tomography in healthy young men at rest and during supine bicycle exercise. Results: Resting MBF was not significantly different between the three myocardial regions. Exercise increased MBF in the LVFW and septum, but MBF was lower in the RV compared to septum and LVFW during exercise. Resting OEF was similar between the three different myocardial regions (~70%) and increased in response to exercise similarly in all regions. MVO2 increased approximately two to three times from rest to exercise in all myocardial regions, but was significantly lower in the RV during exercise as compared to septum LVFW. Conclusion: MBF, OEF, and MVO2 can be assessed simultaneously in the RV and LV myocardia at rest and during exercise. Although there are no major differences in the MBF and OEF between LV and RV myocardial regions in the resting myocardium, MVO2 per gram of myocardium appears to be lower the RV in the exercising healthy human heart due to lower mean blood flow. The presented method may provide valuable insights for the assessment of MBF, OEF and MVO2 in hearts in different pathophysiological states. [ABSTRACT FROM AUTHOR]

Aims Absolute quantification of myocardial blood flow (MBF) with 15O-water cardiac positron emission tomography (PET)/CT has recently demonstrated to hold promising diagnostic value for the detection of coronary artery disease (CAD). However, methodological differences in utilized analysis software packages (SP) could affect generated MBF values, potentially prohibiting widespread clinical applicability of obtained normal thresholds. The aim of this study was to compare two validated non-commercial SP, Carimas and Cardiac VUer, for the quantification of MBF using 15O-water PET. Methods and results One hundred patients with intermediate likelihood of CAD and scanned in academic centres in Amsterdam (n = 50) and Turku (n = 50) were included in the study. Patients underwent a 15O-water PET/CT scan during rest and vasodilator stress based on clinical indications. A single observer, blinded from clinical results and with no prior experience in either SP, analysed all patients twice with both SP. Reproducibility of each SP was assessed using intraclass correlation coefficients (ICC). Intersoftware agreement was assessed using paired t-tests and linear regression. ICC was excellent for each SP for both global and regional MBF (ICC >0.90). Global MBF was comparable between Carimas and Cardiac VUer during rest (1.02 ± 0.28 vs. 0.99 ± 0.23 mL min–1g−1, respectively, P = 0.07), and slightly higher for Carimas during stress (2.73 ± 0.82 vs. 2.63 ± 0.84 mL min−1g−1, respectively, P = 0.01). At a regional level, for resting conditions small (<10%) but significant discrepancies were noted in each vascular territory while for stress MBF, a significant difference was only observed for the LAD region. Differences between SP for the LAD territory were abolished after exclusion of the distal apical segment, which is susceptible to spillover artefacts. An excellent correlation between MBF values was found for global (r = 0.96) and regional MBF (r > 0.94 for all). Conclusion For global and regional MBF, Carimas and Cardiac VUer showed excellent agreement and intra-observer reproducibility. These results confirm that, for patients with intermediate likelihood of CAD, these validated SP are interchangeable and can be utilized for routine clinical practice of 15O-water cardiac PET. [ABSTRACT FROM PUBLISHER]