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Background Cardiovascular disease is the most common cause of death after kidney transplantation. Coronary artery disease (CAD) assessment is therefore mandatory in patients evaluated for transplantation. We aimed to assess the diagnostic accuracy for CAD of single-photon emission computed tomography (SPECT) compared to the standards invasive coronary angiography (ICA) and coronary computed tomography angiography (CCTA) in patients evaluated for kidney transplantation. Methods We performed a systematic literature search in PubMed, EMBASE, Web of Science, OvidSP (Medline), The Cochrane Library and Google Scholar. Studies investigating the diagnostic accuracy of myocardial perfusion imaging (MPI) SPECT in patients evaluated for kidney transplantation were retrieved. After a risk of bias assessment using QUADAS-2, a meta-analysis was conducted. Results Out of 1459 records, 13 MPI SPECT studies were included in the meta-analysis with a total of 1245 MPI SPECT scans. There were no studies available with CCTA as reference. Pooled sensitivity of MPI SPECT for CAD was 0.66 (95% CI 0.53 to 0.77), pooled specificity was 0.75 (95% CI 0.63 to 0.84) and the area under the curve (AUC) was 0.76. Positive likelihood ratio was 2.50 (95% CI 1.78 to 3.51) and negative likelihood ratio was 0.41 (95% CI 0.28 to 0.61). Pooled positive predictive value was 64.9% and pooled negative predictive value was 74.1%. Significant heterogeneity existed across the included studies. Conclusions MPI SPECT had a moderate diagnostic accuracy in patients evaluated for kidney transplantation, with a high rate of false-negative findings. The use of an anatomical gold standard against a functional imaging test in the included studies is however suboptimal.

Noninvasive imaging modalities offer the possibility to dynamically evaluate cardiac motion during the cardiac cycle by means of ECG-gated acquisitions. Such motion characterization along with orientation, segmentation preprocessing, and ultimately, phase analysis, can provide quantitative estimates of ventricular mechanical synchrony. Current evidence on the role of mechanical synchrony evaluation is mainly available for echocardiography and gated single-photon emission computed tomography, but less is known about the utilization of gated positron emission tomography (PET). Although data available are sparse, there is indication that mechanical synchrony evaluation can be of diagnostic and prognostic values in patients with known or suspected coronary artery disease-related myocardial ischemia, prediction of response to cardiac resynchronization therapy, and estimation of risk for adverse cardiac events in patients’ heart failure. As such, the evaluation of mechanical ventricular synchrony through phase analysis of gated acquisitions represents a value addition to modern cardiac PET imaging modality, which warrants further research and development in the evaluation of patients with cardiovascular disease. Electronic supplementary material The online version of this article (10.1007/s12350-019-01670-7) contains supplementary material, which is available to authorized users.

Cardiovascular disease is the most common cause of death after kidney transplantation. Coronary artery disease (CAD) assessment is therefore mandatory in patients evaluated for transplantation. We aimed to assess the diagnostic accuracy for CAD of single-photon emission computed tomography (SPECT) compared to the standards invasive coronary angiography (ICA) and coronary computed tomography angiography (CCTA) in patients evaluated for kidney transplantation.We performed a systematic literature search in PubMed, EMBASE, Web of Science, OvidSP (Medline), The Cochrane Library and Google Scholar. Studies investigating the diagnostic accuracy of myocardial perfusion imaging (MPI) SPECT in patients evaluated for kidney transplantation were retrieved. After a risk of bias assessment using QUADAS-2, a meta-analysis was conducted.Out of 1459 records, 13 MPI SPECT studies were included in the meta-analysis with a total of 1245 MPI SPECT scans. There were no studies available with CCTA as reference. Pooled sensitivity of MPI SPECT for CAD was 0.66 (95% CI 0.53 to 0.77), pooled specificity was 0.75 (95% CI 0.63 to 0.84) and the area under the curve (AUC) was 0.76. Positive likelihood ratio was 2.50 (95% CI 1.78 to 3.51) and negative likelihood ratio was 0.41 (95% CI 0.28 to 0.61). Pooled positive predictive value was 64.9% and pooled negative predictive value was 74.1%. Significant heterogeneity existed across the included studies.MPI SPECT had a moderate diagnostic accuracy in patients evaluated for kidney transplantation, with a high rate of false-negative findings. The use of an anatomical gold standard against a functional imaging test in the included studies is however suboptimal.

Background It is thought that heart failure (HF) patients may benefit from the evaluation of mechanical (dys)synchrony, and an independent inverse relationship between myocardial perfusion and ventricular synchrony has been suggested. We explore the relationship between quantitative myocardial perfusion and synchrony parameters when accounting for the presence and extent of fixed perfusion defects in patients with chronic HF. Methods We studied 98 patients with chronic HF who underwent rest and stress Nitrogen-13 ammonia PET. Multivariate analyses of covariance were performed to determine relevant predictors of synchrony (measured as bandwidth, standard deviation, and entropy). Results In our population, there were 43 (44%) women and 55 men with a mean age of 71 ± 9.6 years. The SRS was the strongest independent predictor of mechanical synchrony variables (p Conclusions The existence and extent of fixed perfusion defects, but not the quantitative PET myocardial perfusion parameters (sMBF and MPR), constitute a significant independent predictor of ventricular mechanical synchrony in patients with chronic HF.

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.

Transluminal attenuation gradient (TAG) represents the slope of intraluminal contrast that decreases along a coronary vessel during coronary computed tomography angiography (CCTA). The aim of this study was to determine the added value of TAG to qualitative CCTA assessment of significant stenosis (&gt, 50%) detecting ischemia as determined by stress myocardial blood flow (MBF) or myocardial flow reserve (MFR) measured by positron emission tomography (PET). Individual contributions of TAG, qualitative assessment and the impact of calcium score were also investigated. Methods: We studied 38 consecutive patients that were referred due to suspected or known coronary artery disease (CAD). All patients underwent a two-phase hybrid 13N-ammonia PET/CT and CCTA. Results: TAG and presence of qualitatively assessed significant stenosis, but not calcium score, were associated with stress myocardial blood flow (MBF) and myocardial flow reserve (MFR). The area under the curves (AUC) of the linear predictor model including qualitative assessment and TAG was superior to the AUC of separate qualitative assessment or TAG for the detection of ischemia according to stress MBF (AUCs were: 88% vs. 79% and 77%, p = 0.01 and p = 0.01, respectively). Conclusions: TAG combined with qualitative CCTA assessment improved ischemia detection.

Background The impact of coronary microvascular dysfunction ( CMD ), as diagnosed by reduced coronary flow reserve, on the outcomes of patients with symptoms of myocardial ischemia and nonobstructive coronary artery disease is poorly understood. We performed a systematic review and meta‐analysis of observational studies to determine the association of CMD with outcomes. Methods and Results We searched online databases for studies where coronary flow reserve was measured invasively or noninvasively, clinical events were recorded after determination of coronary flow reserve, and the frequency of those events was reported for patients with and without CMD . The primary outcome was all‐cause mortality. The secondary outcome was major adverse cardiac events, including cardiac or cardiovascular death, nonfatal myocardial infarction, cardiac hospitalization, or coronary revascularization. Estimates of effect were calculated from crude event rates with a random‐effects model. There were 122 deaths in the 4661 patients without CMD (2.6%) and 183 deaths in the 1970 patients with CMD (9.3%). The odds ratio for mortality in patients with CMD compared with those without CMD was 3.93 (95% CI , 2.91–5.30; P CMD (4.5%) and 245 events in the 1447 patients with CMD (16.9%). The odds ratio for major adverse cardiac events in patients with CMD compared with those without CMD was 5.16 (95% CI , 2.81–9.47; P Conclusions CMD is associated with a nearly 4‐fold increase in mortality and a 5‐fold increase in major adverse cardiac events. Future studies are needed to identify effective strategies to diagnose and treat CMD .

Myocardial Bridging (MB) refers to the band of myocardium that abnormally overlies a segment of a coronary artery. This paper quantitatively evaluates the influence of MB of the left anterior descending artery (LAD) on myocardial perfusion of the entire left ventricle. We studied 131 consecutive patients who underwent hybrid rest/stress 13N-ammonia positron emission tomography (PET) and coronary computed tomography angiography (CCTA) due to suspected myocardial ischemia. Patients with previous myocardial infarction and/or significant coronary artery disease (≥ 50% stenosis) were excluded. Myocardial perfusion measurements were compared between patients with and without LAD-MB. Additionally, we evaluated the relationship between anatomical characteristics (length and depth) of LAD-MB and myocardial perfusion measurements. 17 (13%) patients presented a single LAD-MB. Global myocardial perfusion reserve (MPR) was lower in patients with LAD-MB than in patients without LAD-MB (1.9 ± 0.5 vs. 2.3 ± 0.6, p

The aim of this thesis is to expand our understanding of quantitative myocardial perfusion and ventricular synchrony measured by 13N-ammonia Positron Emission Tomography (PET). This thesis starts with a brief description of the production, pharmacokinetic parameters and imaging protocol of 13N-ammonia. Furthermore, it outlines the current clinical role of myocardial perfusion imaging with PET. With regard to the clinical use of quantitative myocardial perfusion, this thesis focuses on the diagnostic and prognostic value of PET. This thesis reports that myocardial bridging, which refers to a band of myocardium overlying a segment of a coronary artery, is related to low flow reserve measured by PET and that patients with chest pain and normal coronary arteries with low perfusion quantification had an increased risk for cardiovascular events. Moreover, it describes the technical principles on the use of PET for mechanical synchrony. Special attention is given to the detection of myocardial stunning and ischemia induced dyssynchrony for the assessment of coronary artery disease and selection of patients with heart failure that may benefit of cardiac resynchronization therapy. This thesis concludes that even though PET has gained popularity for the assessment of coronary artery disease, progress still needs to be made to standardize protocols and to understand other potential clinical applications, such as the assessment of vasodilator capacity as a marker of cardiovascular risk or the assessment of mechanical synchrony in patients with heart failure.

Introduction Establishing the influence of long-term, gender-affirming hormonal treatment (HT) on bone mineral density (BMD) in transgender individuals is important to improve the therapeutic guidelines for these individuals. Aim To examine the effect of long-term HT and gonadectomy on BMD in transgender individuals. Methods 68 transwomen and 43 transmen treated with HT who had undergone gonadectomy participated in this study. Dual-energy x-ray absorptiometry (DXA) scans were performed to measure BMD at the lumbar spine and total hip. Laboratory values related to sex hormones were collected within 3 months of performing the DXA scan and analyzed. Main Outcome Measure BMD and levels of sex hormones in transwomen and transmen. Results In transwomen, the mean BMD values at the lumbar spine and total hip at the first DXA scan were, respectively, 0.99 ± 0.15 g/cm2 (n = 68) and 0.94 ± 0.28 g/cm2 (n = 65). In transmen, the mean BMD values at the lumbar spine and total hip at the first DXA scan were, respectively, 1.08 ± 0.16 g/cm2 (n = 43) and 1.01 ± 0.18 g/cm2 (n = 43). A significant decrease in total hip BMD was found in both transwomen and transmen after 15 years of HT compared with 10 years of HT (P = .02). Conclusion In both transwomen and transmen, a decrease was observed in total hip bone mineral density after 15 years of HT compared to the first 10 years of HT.

We explored agreement in the quantification of myocardial perfusion by cross-comparison of implemented software packages (SPs) in three distinguishable patient profile populations.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.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.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.

It is thought that heart failure (HF) patients may benefit from the evaluation of mechanical (dys)synchrony, and an independent inverse relationship between myocardial perfusion and ventricular synchrony has been suggested. We explore the relationship between quantitative myocardial perfusion and synchrony parameters when accounting for the presence and extent of fixed perfusion defects in patients with chronic HF.We studied 98 patients with chronic HF who underwent rest and stress Nitrogen-13 ammonia PET. Multivariate analyses of covariance were performed to determine relevant predictors of synchrony (measured as bandwidth, standard deviation, and entropy).In our population, there were 43 (44%) women and 55 men with a mean age of 71 ± 9.6 years. The SRS was the strongest independent predictor of mechanical synchrony variables (p .01), among other considered predictors including: age, sex, body mass index, smoking, diabetes mellitus, dyslipidemia, hypertension, rest myocardial blood flow (MBF), and myocardial perfusion reserve (MPR). Results were similar when considering stress MBF instead of MPR.The existence and extent of fixed perfusion defects, but not the quantitative PET myocardial perfusion parameters (sMBF and MPR), constitute a significant independent predictor of ventricular mechanical synchrony in patients with chronic HF.

Patients with chest pain and no obstructive coronary artery disease have shown a high incidence of major adverse cardiovascular events (MACE). We evaluated the role of absolute myocardial perfusion quantification in predicting all-cause mortality and MACE during long-term follow-up in this group of patients.We studied 79 patients who underwent Nitrogen-13 ammonia PET for quantification of global myocardial blood flow (MBF) and myocardial flow reserve (MFR) due to suspected impaired myocardial perfusion. Patients with coronary artery disease (i.e., 30% stenosis in one or more coronary arteries) were excluded. We assessed all-cause mortality and MACE. MACE was defined as the composite incidence of death, myocardial infarction (MI), or hospitalization due to heart failure.Median follow-up was 8 (IQR: 3-14) years. Univariate Cox regression showed that only MFR (P = 0.01) was a predictor of all-cause mortality. Univariate Cox regression analysis showed that both MFR and Stress MBF were predictors of the composite endpoint of MACE (P 0.001 and P = 0.01, respectively).Quantitative assessment of myocardial perfusion may predict all-cause mortality and MACE in patients with chest pain and normal coronary arteries in the long-term follow-up.Los pacientes con dolor torácico y sin enfermedad arterial coronaria obstructiva tienen una alta incidencia de eventos cardiovasculares adversos mayores (ECAM). Evaluamos el papel de cuantificación absoluta de perfusión miocárdica para predecir la mortalidad por cualquier causa y por ECAM en el seguimiento a largo plazo en este grupo de pacientes. MéTODOS: Estudiamos 79 pacientes a quienes se les realizó PET con 13-Nitrógeno Amonia para la cuantificación absoluta del flujo sanguíneo miocárdico global (FSM) y la reserva de flujo miocárdica (RFM) por sospecha de alteraciones en la perfusión miocárdica. Se excluyeron a los pacientes con enfermedad arterial coronaria (estenosis 30% en una o más arterias). Evaluamos las causas de mortalidad y de ECAM. ECAM fue definida como la incidencia combinada de muerte, infarto al miocardio (IM) u hospitalización por falla cardíaca.La media de seguimiento fue de 8 años (IQR: 3-14). La regresión univariada COX mostró que solo la RFM, es un predictor de mortalidad por cualquier causa. El análisis de regresión univariada Cox mostró que tanto la RFM como la FSM en estrés, fueron predictores para el desenlace de ECAM (P 0.001 y P = 0.01, respectivamente). CONCLUSIóN: La evaluación cuantitativa de la perfusión miocárdica, puede predecir la mortalidad por cualquier causa y por ECAM en pacientes con dolor torácico y arterias coronarias normales en el seguimiento a largo plazo.背景: 患有胸痛但无阻塞性冠状动脉疾病的患者仍存在较高的主要不良心血管事件 (MACE) 发生率。 本研究评估了心肌灌注绝对定量对该组患者长期随访期间全因死亡率和 MACE的预测价值。 方法: 共纳入79例疑似心肌缺血患者, 行A certain nombre de patients présentant des douleurs thoraciques sans évidence de coronaropathie obstructive ont une incidence élevée d’événements cardiovasculaires indésirables majeurs. Nous avons étudié le rôle de la quantification absolue de la perfusion myocardique en tant que valeur prédictive de mortalité et d’événements cardiovasculaires majeurs indésirables chez ces patients. MéTHODES: Nous avons étudié 79 patients suspect de maladie coronarienne. Nous avons évalué de manière quantitative leur perfusion myocardique globale et leur réserve de débit myocardique (MFR) par tomographique à positrons à l’ammoniac marqué à l’azote 13. Les patients atteints de maladie coronarienne définie par une sténose de plus de 30% d’une ou de plusieurs artères coronaires ont été exclus. Nous ont évalué la mortalité globale (quelqu’en soient les causes) et les événements cardiovasculaires majeurs indésirables RéSULTATS: Le suivi moyen fut de 8 ans (3-14 ans). L’analyse des données au moyen de la régression univariée de Cox a montré que seul le flux de réserve myocardique (P = 0.01) est un facteur prédictif de mortalité, toutes causes confondues. La même régression statistique a également permis de démontrer que la perfusion myocardique globale et la réserve de débit coronaire sont des paramètres prédictifs déterminant pour la survenue événements cardiovasculaires majeurs indésirables majeurs (P 0.001 et P = 0.01 respectivement).L’évaluation quantitative de la perfusion myocardique des patients présentant des douleurs thoraciques et chez qui les artères coronaires s’avèrent normales permet de prédire le risque de mortalité et la survenue d’événements cardiovasculaires majeurs indésirables dans le suivi à long terme.

BACKGROUND: While (18)F-fluorodeoxyglucose and (18)F-sodium fluoride with positron emission tomography relate with inflammation and calcification, their role in the assessment of patients with Takayasu arteritis has not yet been studied.METHODS: We present 5 patients with suspected active metabolic disease who underwent PET with (18)F-fluorodeoxyglucose and (18)F-sodium fluoride in order to explore the locations and correlations of (18)F-fluorodeoxyglucose and (18)F-sodium fluoride uptakes. Diagnosis of metabolic active disease was based on (18)F-fluorodeoxyglucose uptake.RESULTS: We studied 3 female patients and 2 male patients. Median age was 29 years (min: 19 max: 63). In areas with atherosclerotic plaques, we found a negative correlation between (18)F-sodium fluoride and (18)F-fluorodeoxyglucose uptakes (r = -0.78) (P = .001). Meanwhile, in areas with only metabolic active disease, we found a positive correlation between (18)F-sodium fluoride and (18)F-fluorodeoxyglucose uptakes (r = 0.94) (P = .019).CONCLUSIONS: In Takayasu arteritis, (18)F-sodium fluoride uptake can document different stages of metabolic disease, even in the absence of active metabolic disease or symptoms.

Metabolic syndrome represents a growing burden in the Mexican population with an increasing presence as evidenced by the most recent epidemiological data, showing a prevalence of 49.8 % in 2006. The cardiovascular hazard of metabolic syndrome has been proven in numerous occasions; these patients present an increased risk of cardiovascular dis- ease not only because of epicardial coronary occlusion but also from microvascular disease secondary to endothelial dysfunction. Myocardial perfusion imaging using both single-photon emission computed tomography and positron emission tomography can be effectively used for the evaluation of established coronary artery disease as well as in the assessment of high-risk asymptomatic pa- tients. In this review, we briefly discuss the role of myo- cardial perfusion imaging studies and its current and po- tential applications for patients with metabolic syndrome.

Nowadays, there is a wide array of imaging studies available for the evaluation of coronary artery disease, each with its particular indications and strengths. Cardiac single photon emission tomography is mostly used to evaluate myocardial perfusion, having experienced recent marked improvements in image acquisition. Cardiac PET has its main utility in perfusion imaging, atherosclerosis and endothelial function evaluation, and viability assessment. Cardiovascular computed tomography has long been used as a reference test for non-invasive evaluation of coronary lesions and anatomic characterization. Cardiovascular magnetic resonance is currently the reference standard for non-invasive ventricular function evaluation and myocardial scarring delineation. These specific strengths have been enhanced with the advent of hybrid equipment, offering a true integration of different imaging modalities into a single, simultaneous and comprehensive study.