Multi-task Deep Learning of Myocardial Blood Flow and Cardiovascular Risk Traits from PET Myocardial Perfusion Imaging.

BACKGROUND: Advanced cardiac imaging with positron emission tomography (PET) is a powerful tool for the evaluation of known or suspected cardiovascular disease. Deep learning (DL) offers the possibility to abstract highly complex patterns to optimize classification and prediction tasks. METHODS AND RESULTS: We utilized DL models with a multi-task learning approach to identify an impaired myocardial flow reserve (MFR <2.0 ml/g/min) as well as to classify cardiovascular risk traits (factors), namely sex, diabetes, arterial hypertension, dyslipidemia and smoking at the individual-patient level from PET myocardial perfusion polar maps using transfer learning. Performance was assessed on a hold-out test set through the area under receiver operating curve (AUC). DL achieved the highest AUC of 0.94 [0.87-0.98] in classifying an impaired MFR in reserve perfusion polar maps. Fine-tuned DL for the classification of cardiovascular risk factors yielded the highest performance in the identification of sex from stress polar maps (AUC = 0.81 [0.73, 0.88]). Identification of smoking achieved an AUC = 0.71 [0.58, 0.85] from the analysis of rest polar maps. The identification of dyslipidemia and arterial hypertension showed poor performance and was not statistically significant. CONCLUSION: Multi-task DL for the evaluation of quantitative PET myocardial perfusion polar maps is able to identify an impaired MFR as well as cardiovascular risk traits such as sex, smoking and possibly diabetes at the individual-patient level.

Myocardial perfusion quantification with Rb-82 PET: good interobserver agreement of Carimas software on global, regional, and segmental levels.

PURPOSE: To estimate the interobserver agreement of the Carimas software package (SP) on global, regional, and segmental levels for the most widely used myocardial perfusion PET tracer-Rb-82. MATERIALS AND METHODS: Rest and stress Rb-82 PET scans of 48 patients with suspected or known coronary artery disease (CAD) were analyzed in four centers using the Carimas SP. We considered values to agree if they simultaneously had an intraclass correlation coefficient (ICC) > 0.75 and a difference < 20% of the median across all observers. RESULTS: The median values on the segmental level were 1.08 mL/min/g for rest myocardial blood flow (MBF), 2.24 mL/min/g for stress MBF, and 2.17 for myocardial flow reserve (MFR). For the rest MBF and MFR, all the values at all the levels fulfilled were in excellent agreement. For stress MBF, at the global and regional levels, all the 24 comparisons showed excellent agreement. Only 1 out of 102 segmental comparisons (seg. 14) was over the adequate agreement limit-23.5% of the median value (ICC = 0.95). CONCLUSION: Interobserver agreement for Rb-82 PET myocardial perfusion quantification analyzed with Carimas is good at any LV segmentation level-global, regional, and segmental. It is good for all the estimates-rest MBF, stress MBF, and MFR.

Sex-Based Differences in Unrecognized Myocardial Infarction.

Background Myocardial infarction is an important cause of morbidity and mortality in both men and women. Atypical or the absence of symptoms, more prevalent among women, may contribute to unrecognized myocardial infarctions and missed opportunities for preventive therapies. The aim of this research is to investigate sex-based differences of undiagnosed myocardial infarction in the general population. Methods and Results In the Lifelines Cohort Study, all individuals ≥18 years with a normal baseline ECG were followed from baseline visit till first follow-up visit (≈5 years, n=97 203). Individuals with infarct-related changes between baseline and follow-up ECGs were identified. The age- and sex-specific incidence rates were calculated and sex-specific cardiac symptoms and predictors of unrecognized myocardial infarction were determined. Follow-up ECG was available after a median of 3.8 (25th and 75th percentile: 3.0-4.6) years. During follow-up, 198 women experienced myocardial infarction (incidence rate 1.92 per 1000 persons-years) compared with 365 men (incidence rate 3.30; P<0.001 versus women). In 59 (30%) women, myocardial infarction was unrecognized compared with 60 (16%) men (P<0.001 versus women). Individuals with unrecognized myocardial infarction less often reported specific cardiac symptoms compared with individuals with recognized myocardial infarction. Predictors of unrecognized myocardial infarction were mainly hypertension, smoking, and higher blood glucose level. Conclusions A substantial proportion of myocardial infarctions are unrecognized, especially in women. Opportunities for secondary preventive therapies remain underutilized if myocardial infarction is unrecognized.

Ventricular synchrony is not significantly determined by absolute myocardial perfusion in patients with chronic heart failure: A 13N-ammonia PET study.

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 < .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. 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.

Stress myocardial blood flow correlates with ventricular function and synchrony better than myocardial perfusion reserve: A Nitrogen-13 ammonia PET study.

BACKGROUND: Cardiac PET quantifies stress myocardial blood flow (MBF) and perfusion reserve (MPR), while ECG-gated datasets can measure components of ventricular function simultaneously. Stress MBF seems to outperform MPR in the detection of significant CAD. However, it is uncertain which perfusion measurement is more related to ventricular function. We hypothesized that stress MBF correlates with ventricular function better than MPR in patients studied for suspected myocardial ischemia. METHODS: We studied 248 patients referred to a rest and adenosine-stress Nitrogen-13 ammonia PET. We performed a multivariate analysis using systolic function (left ventricular ejection fraction, LVEF), diastolic function (mean filling rate in diastole, MFR/3), and synchrony (Entropy) as the outcome variables, and stress MBF, MPR, and relevant covariates as the predictors. Secondarily, we repeated the analysis for the subgroup of patients with and without a previous myocardial infarction (MI). RESULTS: 166 male and 82 female patients (mean age 63 ± 11 and 67 ± 11 year, respectively) were included. 60% of the patients presented hypertension, 57% dyslipidemia, 21% type 2 diabetes mellitus, 45% smoking, and 34.7% a previous MI. Mean stress MBF was 1.99 ± 0.75 mL/g/min, MPR = 2.55 ± 0.89, LVEF = 61.6 ± 15%, MFR/3 = 1.12 ± 0.38 EDV/s, and Entropy = 45.6 ± 11.3%. There was a significant correlation between stress MBF (P < .001) and ventricular function. This was stronger than the one for MPR (P = .063). Sex, age, diabetes, and extent of previous MI were also significant predictors. Results were similar for the analyses of the 2 subgroups. CONCLUSION: Stress MBF is better correlated with ventricular function than MPR, as evaluated by Nitrogen-13 ammonia PET, independently from other relevant cardiovascular risk factors and clinical covariates. This relationship between coronary vasodilatory capacity and ventricular function is sustained across groups with and without a previous MI.

Detection of Osteomyelitis in the Diabetic Foot by Imaging Techniques: A Systematic Review and Meta-analysis Comparing MRI, White Blood Cell Scintigraphy, and FDG-PET.

OBJECTIVE: Diagnosing bone infection in the diabetic foot is challenging and often requires several diagnostic procedures, including advanced imaging. We compared the diagnostic performances of MRI, radiolabeled white blood cell (WBC) scintigraphy (either with 99mTc-hexamethylpropyleneamineoxime [HMPAO] or 111In-oxine), and [18F]fluorodeoxyglucose positron emission tomography (18F-FDG-PET)/computed tomography. RESEARCH DESIGN AND METHODS: We searched Medline and Embase as of August 2016 for studies of diagnostic tests on patients known or suspected to have diabetes and a foot infection. We performed a systematic review using criteria recommended by the Cochrane Review of a database that included prospective and retrospective diagnostic studies performed on patients with diabetes in whom there was a clinical suspicion of osteomyelitis of the foot. The preferred reference standard was bone biopsy and subsequent pathological (or microbiological) examination. RESULTS: Our review found 6,649 articles; 3,894 in Medline and 2,755 in Embase. A total of 27 full articles and 2 posters was selected for inclusion in the analysis. The performance characteristics for the 18F-FDG-PET were: sensitivity, 89%; specificity, 92%; diagnostic odds ratio (DOR), 95; positive likelihood ratio (LR), 11; and negative LR, 0.11. For WBC scan with 111In-oxine, the values were: sensitivity, 92%; specificity, 75%; DOR, 34; positive LR, 3.6; and negative LR, 0.1. For WBC scan with 99mTc-HMPAO, the values were: sensitivity, 91%; specificity, 92%; DOR, 118; positive LR, 12; and negative LR, 0.1. Finally, for MRI, the values were: sensitivity, 93%; specificity, 75%; DOR, 37; positive LR, 3.66, and negative LR, 0.10. CONCLUSIONS: The various modalities have similar sensitivity, but 18F-FDG-PET and 99mTc-HMPAO-labeled WBC scintigraphy offer the highest specificity. Larger prospective studies with a direct comparison among the different imaging techniques are required.

Type 2 diabetes mellitus correlates with systolic function during myocardial stress perfusion scanning with Nitrogen-13 ammonia PET.

BACKGROUND: The influence of type 2 diabetes mellitus (DM2) on systolic function is partially determined by the coronary vasodilator function, nevertheless, an independent effect is suspected. We evaluated the relationship between DM2 and systolic function considering PET quantitative myocardial perfusion. METHODS: We analyzed 585 patients without a previous myocardial infarction referred to a rest and adenosine stress Nitrogen-13 ammonia PET. A bootstrapped multiple linear regression analysis was performed using DM2, stress myocardial blood flow (sMBF), myocardial perfusion reserve (MPR), and clinical risk factors as predictors and LVEF as the outcome variable; an interaction term was additionally investigated. RESULTS: Two hundred and ninety male and 295 female patients (mean age 65.3 ± 9.9 and 67.4 ± 10 years, respectively) were included. 57.1% presented hypertension, 16% smoking, 37.6% hypercholesterolemia, 33.8% family history for CAD, and 15.2% DM2. The mean MPR was 2.13 ± 0.48 and 2.21 ± 0.60, mean sMBF was 2.01 ± 0.51 and 2.15 ± 0.54, and mean LVEF was 63% ± 10.4 and 67% ± 10.1 for diabetics and non-diabetics, respectively. A significant relation was detected for sMBF (B = 5.830 95% CI [3.505, 9.549], P = .001) and DM2 (B = -2.599 95% CI [-5.125, -0.119], P = .03) with LVEF. The interaction (DM2 × sMBF) yielded no significance (P = .512). CONCLUSION: DM2 influences PET-measured systolic function in patients without previous myocardial infarction independently from myocardial perfusion parameters. Our study supports the importance of DM2 as an independent risk factor for deteriorating systolic function.

[18F]-Sodium fluoride uptake in Takayasu arteritis.

BACKGROUND: While 18F-fluorodeoxyglucose and 18F-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 18F-fluorodeoxyglucose and 18F-sodium fluoride in order to explore the locations and correlations of 18F-fluorodeoxyglucose and 18F-sodium fluoride uptakes. Diagnosis of metabolic active disease was based on 18F-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 18F-sodium fluoride and 18F-fluorodeoxyglucose uptakes (r = -0.78) (P = .001). Meanwhile, in areas with only metabolic active disease, we found a positive correlation between 18F-sodium fluoride and 18F-fluorodeoxyglucose uptakes (r = 0.94) (P = .019). CONCLUSIONS: In Takayasu arteritis, 18F-sodium fluoride uptake can document different stages of metabolic disease, even in the absence of active metabolic disease or symptoms.

Endocarditis infecciosa en un paciente con válvula aórtica bicúspide: Reporte y revisión de un caso / Infective endocarditis in a patient with bicuspid aortic valve: a case report and review

Resumen La endocarditis infecciosa es una patología que requiere un diagnóstico y tratamiento oportuno para prevenir sus graves complicaciones y, ante todo, evitar la muerte del paciente. En el presente artículo, documentamos el abordaje diagnóstico y terapéutico de un caso de endocarditis, en el escenario de una cardiopatía congénita, válvula aórtica bicúspide, atendida en el Instituto Nacional de Cardiología "Ignacio Chávez".

Abstract Infective endocarditis is a condition that requires an early diagnosis and treatment to prevent its severe complications and, above all, avoid death. In this article we document the diagnosis and therapeutics of a case of infective endocarditis in the setting of a congenital heart disease, bicuspid aortic valve, referred to the National Institute of Cardiology "Ignacio Chávez".

Evaluation and analysis of plasma soluble adhesion molecules in patients with coronary ectasia and atherosclerotic coronary artery disease.

BACKGROUND AND AIMS: The pathogenesis of coronary artery ectasia (CE) is poorly understood. An underlying inflammatory process is suspected; current therapy aims to prevent thrombotic events. Presently, there is no evidence to support an anti-inflammatory approach for CE patients. We undertook this study to determine the presence and levels of adhesion molecules as well as other inflammation-related markers and evaluate their invasive angiography findings to compare between patients with CE or atherosclerotic coronary artery disease (CAD). METHODS: We included 23 patients with CE alone and 23 patients with CAD alone reported by diagnostic angiography. The two groups were paired according to gender and age. Clinical variables, angiographic findings (STEMI, NSTEMI, previous coronary stenting and previous CABG), serum VCAM, ICAM, C-reactive protein (CRP), IL-6 and adiponectin were compared between groups. RESULTS: In patients with CE, median for serum VCAM was 1700 ng/mL with a range from 900-4050 and for serum ICAM was 550 ng/mL (370-1530); in contrast to the obstructive lesions group where we found a median for VCAM of 1150 ng/mL (650-2000) and for ICAM of 370 ng/mL (150-480). Both measurements achieved statistical significance with a p value = 0.0001. There was no important variation between patients measured at different times from diagnosis. CONCLUSION: Plasma soluble adhesion molecules in CE are elevated in comparison to CAD. The presence of high levels of these molecules, along with not uncommon multivessel and extensive coronary affection suggest the participation of subclinical inflammation, which may have an important role in the development of CE.

Estenosis aórtica supravalvular: reporte de caso clínico y revisión bibliográfica / Supravalvular aortic stenosis: clinical case report and review

Resumen La estenosis aórtica supravalvular es una lesión congénita obstructiva del tracto de salida del ventrículo izquierdo. Es la forma menos frecuente dentro de este grupo de lesiones, las cuales, a su vez representan el 6% de las cardiopatías congénitas en pacientes pediátricos. Esta cardiopatía se relaciona más con pacientes pediátricos, sin embargo, presentamos el caso de un paciente masculino de 23 años de edad quien acudió al hospital por haber presentado episodio de disnea súbita en reposo, acompañada de diaforesis, dolor torácico opresivo sin irradiaciones y síncope. Se realizó un ecocardiograma transtorácico con el cual se diagnosticó estenosis aórtica supravalvular.

Abstract Supravalvular aortic stenosis is a left ventricular outflow tract obstructive lesion. It is the least common form of this group of lesions, which only represents 6% of congenital heart disease in children. This condition is commonly diagnosed during childhood; however we present the case of a 23 year old man who was taken to the hospital for having presented a sudden dyspnea episode with diaphoresis, chest pain without radiation and syncope. He was diagnosed with supravalvular aortic stenosis after echocardiography.

Anomalía de Ebstein / Ebstein's anomaly

La anomalía de Ebstein es una cardiopatía congénita compleja, caracterizada por el adosamiento de los velos valvulares tricuspídeos posterior y septal al endocardio ventricular derecho, lo que condiciona el desplazamiento del orificio valvular hacia la porción apical del ventrículo derecho, dando por resultado una atrialización de dicho ventrículo. El primer caso reportado en la literatura data del año 1866 por el médico Wilhelm Ebstein. Las manifestaciones clínicas son muy variables; entre las más frecuentes destacan: cianosis progresiva, disnea, insuficiencia cardiaca, palpitaciones y arritmias. El abordaje del paciente debe incluir electrocardiograma, radiografía de tórax y ecocardiograma transtorácico, siendo este último el estándar de oro para establecer el diagnóstico. Únicamente aquellos pacientes que cumplan con los criterios establecidos deberán someterse a tratamiento quirúrgico. Dada la alta similitud de la anomalía de Ebstein con otras displasias de la válvula tricúspide, es fundamental llevar a cabo una evaluación multidisciplinaria para establecer un diagnóstico y tratamiento precisos.

Ebstein's anomaly is a congenital malformation that is characterized primarily by abnormalities of the tricuspid valve and right ventricle, specifically tethering of the posterior and septal tricuspid valve leaflets to the right ventricle endocardium resulting in an apical displacement of tricuspid ring. The first reported case dates back to 1866 by Wilhelm Ebstein. Clinical presentation varies among patients. The most common symptoms are: progressive cyanosis, exertional dyspnea, heart failure, palpitations and arrhythmias. Patient approach should include electrocardiogram, chest X-ray and transthoracic echocardiogram, the latter being the gold standard for diagnosis. Only those patients who meet established criteria will undergo surgical treatment. Given the high similarity of Ebstein's anomaly with other dysplasias of the tricuspid valve, it is essential to conduct a multidisciplinary evaluation to establish an accurate diagnosis and treatment.